FAQ on print, design, reprographics,
large format and web
Browse below in our categories to find the question you need answering on FAQ on print. If it not there ask us by email, well do out best to answer your problem.
What’s the difference between vector, raster and bitmap images?
Here we tell you what’s the difference between vector, raster and bitmap images and what they are used for?
Raster Graphics (commonly called bitmap images) are made of pixels. Each pixel is actually a very small square that is assigned a colour when photographed or scanned. Each pixel makes up the image as a series of share dots. When you zoom in on a bitmap image you can see the individual pixels that make up that image. They have a fixed resolution and cannot be resized larger without losing quality.
- Common bitmap file formats are .jpg .gif .png .tiff .psd and .bmp
Often bitmap images have much larger file sizes than a vector graphic. They are often compressed to reduce their size and therefore loose further clarity. Bitmap images can be converted from one format to another with programs such as Photoshop. A .jpeg can be save to a .tiff or .jpeg to a .psd or .png (see link below).
Vector graphics or vector images are images that have been created in a vector drawing programs such as Corel or Illustrator. The paths and shapes created are processed mathematically. Vector art is resolution independent whatever size you enlarge the image, the output quality is never compromised. This is why logos and line illustrations should always be created in vector art format.
- Common vector art file formats for include: .ai .eps and .pdf
Understanding raster images and vector graphics is important. Choosing which style to use could end costs far more than expected along with the printed result not being as expected. Without exception logos should always be created in vector art format because as we have said it is scalable — able to be enlarged without any loss of quality.
Can I make my jpeg into vector art?
Simply answer is No If your logo never was vector, or if the original art file has been lost. The only real alternative is to have a professional graphic artist create the logo from scratch in a vector drawing program. It is possible to convert raster art into vector with methods such as “live trace” in Adobe Illustrator, the results are usually less than satisfactory but occasionally it still surprises us.
Saving your logo to a different file format
It is a common misconception that saving a raster art file (such as a logo) to a vector art file format will somehow fix the problem. Pixel-based raster art will always be made out of pixels, regardless of what file format one saves the image as. If you have poor quality images changing them to a different format will not help. Save a jpeg as a larger file is pointless and will make the image worse.
Is vector art always better?
Most marketing materials actually contain a combination of both raster and vector art formats. An understanding of the advantages & limitations of each format and the relationship between them is most likely to result in efficient and effective use of tools.
Vector art is complementary, and not necessarily always “better” than raster art. A real photograph can’t be vector art, that would be an illustration. Bitmap formats are best for images that need to have a wide range of color gradations, such as most photographs. Vector formats, on the other hand, are better for images that consist of a few areas of solid color. Examples of images that are well suited for the vector format include logos and type.
With Adobes Creative Cloud you can now happy produce artwork in Photoshop knowing that type and images will maintain their quality. This of course has not always been the case. Only a few years ago you would have never create a business card in Photoshop the quality would have been quite poor. Technology moves forward and today you can produce print ready artwork in Photoshop, edit images in Illustrator and produce websites in InDesign. Even Acrobat gets in the act. We would recommend that you use the correct application specifically designed for the job:-
- Photoshop, Pixir Editor or perhaps GIMP
- Illustrator, Corel or SVG Edit
Page Make up
- InDesign, Quark or Affinity Publisher
Image by Pexels
Why is Google so important for your business?
Understanding why Google is so important and how to improve your ranking
The reason for Google being so important is that in the UK more than 90% of all web traffic runs through its search engine. Those companies at the top of each page pay for that position. You can understand why Google earns Trillions of revenue every year.
£250 can buy a lot. £250,000 can buy you a whole lot more. The same is with your page ranking, it you have the money you can always be number one. But sometimes, those who are not so cash rich or are simply starting up you have no chance in competing with multinationals. But what you can do is to be faster, smarter and intuitive something bigger companies completely lack. You can get a whole lot more for next to nothing if you know how to play the game.
SEO is complicated. For every company there will be a different approach, different set of rules, a different path to follow, which in itself makes any SEO work time consuming. But there are a quite few things you can do as a business that will generate more response.
A few points worth remembering
It is not ranking number one that brings in the sales. There is no point is spending more money promoting your page if you do not generate enough income from it. It is exactly the same as traditional marketing. Work out what is your budget and how best to use it to generate the maximum return.
Let’s be honest, you’re never going to rank number one in a crowded field of competitors who’s own own agenda is to be number one. What you need is a company that will look at your options, plan and implement a route that is monitored at every stage to ensure your on track. It so easy writing this, but in reality its hard work and a lot of effort, a whole raft of things can be done to generate response from a web site that will improve your sales. This will also naturally improve your ranking position.
How we can help
There are companies, many from overseas who promise to rank your website at number one. Yes it can be done, but it will not one for the key words your envisaged. At Pre Press we will never say you’ll be number one, we will say we will make a big difference. We make the difference by working together, helping you generate more response from your web site with the lowest possible outlay and the maximum possible return.
Pre Press offer a wide range of fully managed digital marketing services including SEO-optimised website design and hosting.
What is Spot colour and when do you use it?
In terms of brand spot colour is invaluable, it gives reliable, specified printed colour that matches across various printed items
Spot colour in litho or offset printing is a single colour generated by a specified ink that is printed using a single plate.
In the full colour printing process the basic printing colours are CMYK. Those four colours will print to offer virtually every colour you can imagine, but not all. The CMYK process is not perfect, it is flawed. For instance it cannot reproduce all the colours from your computer screen, there are print variables such as dot gain and paper substrates differ to each other, all of which shifts colour. To create consistencey the Pantone system is used by the world the offer a system where colour does not shift or change.
You can have a spot colour in a two colour job – Back and Pantone 032 for instance, or two Pantone numbers. Same applies to a three colour job.
The Pantone System
The Pantone systems was devised in the USA and has become adopted by the print industry. The idea behind the PMS is to allow designers to match specific colours when a design enters production stage, regardless of the equipment used to print the colour.
When you specify a spot colour from the Pantone range it will offer a CMYK breakdown. You would notice from the swatch that the spot colour is different from the CMYK. If you choose the Pantone it will print that colour, if you choose to print your Pantone colour as a CMYK colour then the right hand image will be more representative of the printed colour. Some Pantone colour translate to CMYK extremely well while others cannot be replicated at all. We always design with this in mind as it can save a client a considerable amount of money.
Almost certainly for brand colour you should specify a Spot colour in the printing process. An addition fifth plate is added during the printing process which when printed is exactly the same of the Spot colour on the Pantone swatch. You are not limited to one, it is possible to add a sixth, or seventh plate to the printing process..
When making a multi-color print with a spot color process, every spot color needs its own lithographic plate. All the areas of the same spot color are printed using the same film, hence, using the same lithographic plate. The dot gain, hence the screen angle and line frequency, of a spot color vary according to its intended purpose.
Spot lamination and UV coatings
Spot lamination and UV coatings are also referred to as ‘spot colors’, as they share the characteristics of requiring a separate lithographic film and print run.
The widespread offset-printing process is composed of four spot colours: Cyan, Magenta, Yellow and Black commonly referred to as CMYK. More advanced processes involve the use of six spot colors (hexachromatic process). This adds Orange and Green to the process (termed CMYKOG). The two additional spot colors are added to compensate for the ineffective reproduction of faint tints using CMYK colors only. However, offset technicians around the world use the term spot colour to mean any colour generated by a non-standard offset ink; such as metallic, fluorescent, spot varnish, or custom hand-mixed inks.
- Pantone, has been dominant spot color printing system since 1980’s.
- Toyo and DIC are common spot color system in Japan.
- RAL (color space system) is a color matching system used in Europe. The so-called RAL CLASSIC system is mainly used for varnish and powder coating.
First printed by Pre Press 2002/2008/2014/2020
Never use JPEG in your workflow
JPEG’s save space, allow faster loading, processing and ripping, they also give good colour reproduction, so why should you never use JPEG’s in a print workflow?
JPEG’s are possibly one of the biggest pains in reprographics. Next to LZW Tiff files they cock up more ‘quality’ jobs than any other file format and believe us over last 30 years of digital reprographics we have seen hundreds. Many of today’s brochures and magazine use JPEG’s quite successfully. They have numerous advantages over other file types, which is why they are so common. But in the wrong hands they will ruin any job.
Compared to a PSD or Tiff file, JPEG’s are lower quality. You can more or less always tell that a particular image was saved as a JPEG because in areas with strong contrast you can see compression artefacts. The stronger the compression the more JPEG noise or artefacts. Most other file formats use lossless compression. These files are larger than JPEG because they use a fully recoverable (lossless) compression that preserves all of the original image data. These file formats offer full quality at all times, no matter how many times they are saved.
This is why you never use a jpeg
JPEG compression algorithm changes image data while converting it. Amount of change can be controlled, but not its location which is always noticeable around sharp colour changes and across gradient areas.
JPEG FILES WORK BY THROWING AWAY DATA. THIS DATA CANNOT BE REPLACED – EVER.
If you use JPEG’s in your workflow then somebody, at some point in the future is going to use this file incorrectly. They are going to increase its size to save time, they save again reducing further the quality. While many JPEG’s, even poor quality ones print ok, do you really want to loose a customer because of an error than can be avoided simply by using a better quality workflow?
JPEG general information
- JPEG is primarily an RGB format.
- It is also fine for print but beware it’s pitfalls.
- If you save a JPEG image several times, you’d end up with an unusable image. Because every time you save you throw away even more data. Photographers always make the mistake of saving their JPEG file again, thus giving the end user an inferior file to their own original.
- JPEG’s cannot be restored to its original.
- You can remove some compression artefacts in Photoshop.
- In print always save JPEG at the highest possible quality and set to baseline standard.
- For web save at Quality 8 or 10 progressive. Remember this image should be optimised when in your chosen app.
When to use JPEG
If you are processing 100’s of files every day, JPEG’s being a smaller file offers a credible and faster solution. It is deciding when you can use a JPEG and when not.
Newspapers are typically printed in a resolution of 85 lpi, while some magazines may print at 133lpi or 150lpi. At these lines per inch even poor quality images print reasonably well. If you are producing in a hi end magazines or brochures for printing at 200lpi or stochastic printing, quality is everything and poor image will be noticed especially against a quality image.
TIFF general info
- TIFF is best file format for printing
- It’s perfectly natural for a TIFF file to save image data in CMYK colour space which is used in press.
- TIFF can also compress image data but uses such an algorithm that doesn’t change source data (lossless compression). But please do not use this option.
- TIFF format also supports alpha channel (transparency).
- If you’d be opening and saving the same TIFF file, you’ll end up with exactly the same image as source. Nothing would change in terms of image data.
There is nothing inherently wrong with a JPEG file if you know what you are doing. But when it comes to your print workflow RAW, TIFF and PSD files are far superior. Unlike 20 years ago when disk space was at a premium today, there is no excuse in compressing files. Terabyte storing and large format transfer means that 300mb files are common place.
Pre Press recommend that your master file should be 400dpi at original size supplied as an RGB. Covert to CMYK if you need. If you understand ICC profiling then add this, if not, switch all colour profiling off.
If you want your images to stay as true to original as possible save with PSD or TIFF file format. This PSD file format can be used in all page make up programs including InDesign and Quark with no problems. If you prefer a TIFF file format that also is fine and our preference. However DO NOT SAVE WITH LZW COMPRESSION these files will often give unexpected print results – you have been warned.
Images for print
- Save as PSD or Tiff with no compression
- CMYK as colour mode
- A minimum of 350dpi at 100% for 200lpi
- A minimum of 300dpi at 100% for 150lpi
- Colour settings are normally FORGR39. Check with your printer
Images for web
- For images JPEG
- Recommended 72dpi
- Switch colour settings off
- Logos and other graphics we recommend the PNG file format
Images for large format
- RGB or CMYK*
- Images PSD or TIFF or EPS
- Recommended 300dpi at 25% minimum
- Switch colour settings off or use FOGRA39. Check with your printer
- Ensure that your photograph is taken at the highest resolution possible. and save at 400dpi. Why this high?, Rule of thumb is twice the dpi to the lpi. 300dpi is suitable for presses that run screen of 150lpi. These days most good printers use 200 line screen which need a higher resolution – hence 4oodpi. Also you many need to use this image again for large format work. So with have one master file for everything or several files at the correct size.
- All photography should be taken and supplied as RAW files. Note Photoshop will open these as 8bit files only, you have to tell it to open at 16bit.
- The advantages of 16 bit files are clear to see. Better gradients, better shadow areas, more control and a dam sight quicker to put a clipping path around an image.
- Insist that your Photographer supplies RAW files only.
- Ask your printer for help or even a specification guide.
- Ensure you understand how to correctly make a PDF, Remember when making a PDF it compresses images.
- The name “JPEG” stands for Joint Photographic Experts Group, the name of the committee that created the JPEG standard and other still picture coding standards.
- Remember if you supply your image too small it will print badly.
- If you supply a image that is too large it will print perfectly.
* Note printing RGB images on large format printers offer a far larger colour range than CMYK
This FAQ was first written April 1999. Updated 2005/2014/2020
What is the difference between UV Varnishing, varnishing and laminating?
Clients often become confused with the various finishes that can be applied to printing materials. Not knowing the right one can cause problems so its important that when ordering that you tell your printer exactly what you require.
So, what is the difference between UV Varnishing, varnishing and laminating? There are several kinds of varnish that can be applied to printing, but all share some common characteristics. Here are a a few basic pointers.
- A varnish increases colour absorption
- They speed up the drying process.
- The varnish helps to prevent the ink from rubbing off when the paper is subjected to handling.
- Varnishes are used most frequently and succesfully on coated papers.
- Laminates are best for protection
A machine seal is a basic, and virtually invisible coating applied as part of the printing process or offline after the project leaves the press. It does not affect the appearance of the job, but as it seals the ink under a protective coat, the printer need not wait so long for the job to be dry enough to handle. It is often used when producing fast turnaround printing such as leaflets on matt and satin papers, as inks dry more slowly on these materials. Different coatings are available in different finishes, tints, textures and thicknesses, which may be used to adjust the level of protection or achieve different visual effects. Areas that are heavily covered with black ink or other dark colours often receive a protective coating to guard against fingerprints, which stand out against a dark background. Coatings are also used on magazine and report covers and on other publications that are subject to rough or frequent handling.
Liquid coatings are by far the most common way to protect print publications. They provide light to medium protection at a relatively low cost. Three major types of coatings are used:
A varnish is a liquid coating applied to a printed surface. It is also referred to as coating or sealing. It is noramlly used to prevent rubbing or scuffing and ofteen used on coated stock. Varnish or print varnish is a clear coating that can be processed like an ink in (offset) presses. It has a similar composition to ink, but lacks any color pigment There are two forms
- Varnish: A clear liquid applied to printed surfaces for looks and protection.
- UV coating: Liquid laminate bonded and cured with ultraviolet light. Environmentally friendly.
Ultraviolet light. It can be a gloss or a matt coating. It can be used as a spot covering to accent a particular image on the sheet or as an overall flood coating. UV coating gives more protection and sheen than either varnish or aqueous coating. Since it is cured with light and not heat, no solvents enter the atmosphere. However, it is more difficult to recycle than the other coatings. UV coating is applied as a separate finishing operation as a flood coating or (applied by screen printing) as a spot coating. Keep in mind that this thick coating may crack when scored or folded.
Varnish coating are available in gloss, satin or matt finishes, with or without tints. Varnishes offer a relatively low degree of protection compared to other coatings and laminates, but they are used widely, thanks to their low cost, flexibility and ease of application. Varnishes are applied just like an ink, using one of the units on the press. Varnish can either be flooded across the entire sheet or spot applied precisely where desired, to add extra gloss to photos, for example, or to protect black backgrounds. Although varnishes must be handled carefully to prevent the release of harmful volatile organic compounds into the atmosphere, when dry they are odorless and inert.
Aqueous coating is more environmentally friendly than UV coating because it is water based. It has better hold-out than varnish (it does not seep into the press sheet) and does not crack or scuff easily. Aqueous does, however, cost twice as much as varnish. Since it is applied by an aqueous coating tower at the delivery end of the press, one can only lay down a flood aqueous coating, not a localized “spot” aqueous coating. Aqueous comes in gloss, dull, and satin. Like varnishes, aqueous coatings are applied inline on press, but they are shinier and smoother than varnish, have higher abrasion and rub resistance, are less likely to yellow and are more environmentally friendly. Aqueous coatings dry faster than varnishes too, which means faster turnaround times on the press.
Available in gloss or matt finishes, water based coatings offer other advantages as well. Because they seal the ink from the air, they can help prevent metallic inks from tarnishing. Specially formulated aqueous coatings can be written on with a number two pencil, or overprinted using a laser jet printer, a key consideration in mass mail projects.
Aqueous coatings and UV coatings as well are also susceptible to chemical burning. In a very small percentage of projects, for reasons not fully understood, certain reds, blues and yellows, such as reflex blue, rhodamine violet and purple and pms warm red, have been known to change color, bleed or burn out. Heat, exposure to light, and the passage of time can all contribute to the problem of these fugitive colors, which may change at any point from immediately after the job leaves the press to months or years later. Light tints of colors, made using a 25% screen or less, are especially prone to burning.
To help combat the problem, ink companies now offer more stable, substitute inks that are close in color to ones that tend to burn, and these inks are often used to print light tints or bright colors. Even so, burning can still occur and dramatically affect the look of the project.
Laminate is a thin transparent plastic sheet or coating that is usually applied to covers, post cards, etc. providing protection against liquid and heavy use, and usually accents existing colour, giving a high gloss effect. Laminates come in two types: film and liquid, and can have a gloss or matt finish. As their name suggests, in one case a clear plastic film is laid down over the sheet of paper, and in the other case a clear liquid is spread over the sheet and dries (or cures) like a varnish. Laminates protect the sheet from water and are therefore good for coating items like menus and book covers. Laminates are slow to apply and costly but provide a strong, washable surface. They are the superior choice for protecting covers.
Which varnish is right for your job?
Laminates offer the greatest protection and are unbeatable in a variety of applications, from maps to the menus, business cards to magazines. But with their greater weight, time, complexity and expense, laminates are typically not suited for projects with extremely large press runs, limited life spans or short deadlines. If laminates are used, there may be more than one way to achieve the desired results. Combining a laminate with a heavier paper stock produces a thicker finish at a lower cost.
If you can’t decide, remember that the two types of finishes can be used together. A spot matte UV coating, for example, could be applied over a gloss laminate. If the project will be laminated, make sure to factor in additional time and often, additional weight if mailing.
How to use coated paper
No matter what coating you use, the results will look always look better on coated paper. This is because of the the hard, nonporous surface of the stock holds the liquid coating or film on the top of the paper, without allowing it to run into in to the surface of uncoated stocks. This superior holdout helps ensure that the protective finish will go on smoothly. The smoother the surface, the better the quality.
What is dot gain?
Here we help explain what is dot gain and how it affects your print
First of all there will be a lot of ‘industry’ people couldn’t tell you what is dot gain. They probably wouldn’t know the CMYK print angles they use or why it is generated. So you’re not alone. We are going to explain here what is dot gain briefly so you understand the basics and can get on with your job.
If you are using the latest applications and printing on a modern automatic sheet fed offset press than pretty much you don’t have to worry. There will be little chance of any problem. Your printers’ pre press department will take care of everything as part of their workflow, even small printers will have this area web covered. If you are however experiencing a problems, particularly with flexo printing then you need to read further, you’ll also need to understand chokes and spreads.
We all know that print is made up of dots. These dots or halftones are what go together to make an image or produce a printed colour. CMYK – Cyan Yellow Magenta and Black. These dots are automatically created when your digital image is made into film or plate.
Definition of dot gain
It is defined as the increase in the area fraction of a halftone dot during the prepress and printing processes. Total dot gain is the difference between the dot size on the film/plate and the corresponding printed dot size. When you output to film or direct to plate the dot will increase. When ink hits paper it spreads.
Dot gain is something that happens on all printing presses it cannot be avoided you cannot stop it. The important thing is it can be allowed for. Prepress and press operators can minimise dot gain but cannot avoid that dot gain occurs. As such it is also the responsibility of the designer to be aware of dot gain and to anticipate its effect.
Dots start from 1% (tint) to 100% – 100% being black. Some printing presses simply cannot print a 5% tint or less (nothing prints) and anything over 92% will fill in and print solid black. So we have to compensate for these areas. The complication starts because there are different types of dot gain which occur throughout the reprographics and particularly the printing process.
Dot gain happens because the diameter of halftone dots increases during the prepress and printing process. The size of each dot can increase when film, film & plates are made as well as physical distortion from the printing press and the physical properties of the ink and paper and these intern are affect by temperature and humidity.
How to find out about what dot gain to use?
Easy one this, telephone the printer and ask – they will be absolutely delighted that you are saving him time and money by sending in your job right first time. They will or should send you a specification sheet, simply follow that information.
How do I Control dot gain?
As we have said if it is a standard job like a filer or leaflet, perhaps a magazine then it will with be digitally printed lithographically. Most of todays applications automatically adjust for this. The example here is Adobe Bridge which sets the colour for all Adobe products who have. Learn more here
In Adobe Photoshop CC dot gain is automatically adjusted depending on the colour setting you have chosen. You Can control your work flow using Adobe Bridge. You can also manually adjust using the transfer function dialogue box for each individual image. We recommend this especially when combining colour critical black and white with full colour images on a job.
Colour settings in Bridge are made under ‘Edit’ in the main menu bar
Choose your preferred Colour Settings, this setting will be applied to all your Creative Cloud Apps
Dot gain basics
Inherent to the printing process dot gain will always be a problem. It has many sources all of which are unique to a specific printing environment. Therefore, because Printer A has presses printing with 18% dot gain and Printer B prints with 24% does not mean A is better press or is a better printer than B, it just means they are different.
It is also affected by the paper that is used, the ink, the ink colour, the type of printing press, the roller pressure, the age of the press, how it is maintained and the press speed can all have an affect. Therefore, the gain for each colour of ink used in the print must be measured to accurately portray the gain. Printers always want to run their presses as fast as possible this also affects trap, dot and registration amongst other things.
It can be expressed as a numerical value. It equates the difference between the wanted value and the resulting value. if a printed page of 30%, flat tint, but after measuring the printed result, this flat tint is now 35%, the dot gain equals 5%.
For example, if we have a 50% tone, and expect a total gain of 24% during printing, then the measurement of the corresponding tone patch on the press sheet should have a value of 74%. If our reading yields a value significantly different than this expected size of 74%, then our processes should be examined to determine the cause for failure.
You can measure dot gain with a densitometer and a colour bar. It is usually measured with 40% and 80% tones as reference values. A common value is around 23% in the 40% tone for a 150 lines per inch screen and coated paper.
Often on newspapers, packaging you will see various tint bars, solids and alignment circles, these are all there to help the printer achieve best results.These test strips, called print control strips or colour bars, consist of strips of film containing the various test elements for each of the four colors. In some cases six color versions are available when special colors might be used. The usual densitometric targets in a color bar are: Solid Ink Density, Dot Area/Gain of the quarter, half and three-quarter tints, Contrast and the Trapping of ink overprints.
Created by freepik – www.freepik.com
Types of dot gain
There are different types of dot gain in the prepress and printing process.
Imaging devices & media
The optical system in computer to plate systems or imagesetters is not always perfectly linear. In order to make sure that the media are exposed sufficiently, the laser beam is a bit wider than needed so that the lines that are exposed slightly overlap each other. Depending on the process (positive/negative), this may cause either a slight dot gain or a dot loss.
Media such as plates or film also can be non-linear: some are but polymer plates, for instance, can have a dot gain of 5 percent of so.
Mechanical dot gain can be summed up as any physical growth or loss the dot experiences by things like gear play or over-exposure. Mechanical dot gain in turn is divided into two sub- groups: directional and non-directional.
Directional dot gain would be dot gain incurred through doubling or slurring. Slur is the deformation of a dot due to surface speed difference of two cylinders. The difference in speed causes the dot to elongate in the printing direction. Although often present, slur has no significant contribution to overall dot gain. It typically adds only 1% to 2% in the worst cases. Doubling is basically a registration problem on multi-colour presses
Essentially Ink is transferred from the printing plate to the blanket and from the blanket to the paper. Each time pressure is applied, increasing the physical diameter of the printed dot. The ink that is used, the fountain solution, the blanket, the pressure (over/under packing) and the speed at which the press runs all influence this area.
When ink is absorbed in the paper is spreads in all direction increasing the dot diameter. This effect is more pronounced 0n newsprint, plastics, foil and uncoated paper than it is on coated stock.
Optical dot gain refers to the appearance of a given halftone to the human eye, or densitometer, when viewed at normal viewing conditions. When light hits the printed surface, it becomes slightly diffused around the dots. The human eye (as well as measuring devices) perceive this as a darkening. Dots appear to be larger than they really are.
Applications like Adobe Photoshop will automatically compensate when images are converted from RGB to CMYK. This is done based on the selected preferences set in Photoshop or Adobe Bridge. All designers need to be aware of this (see above) and make sure that their software is correctly configured for the printing process that will be used to print their job. They also need to be aware that vector based applications don’t compensate for dot gain. If you draw infographics for a newspaper, you need to make sure that flat tints don’t get too dark in print and allow for this.
Prepress operators are expected to make sure that plates delivered to the press are linear, with a typical tolerance of around 2%. Today’s highly automative systems come with calibration tools to achieve this. If a system has 5% gain, instructing the RIP to image a 50% tint as a 45% tint assures that the end result is once again 50%. This process is called linearization.
Given the fact that so many people supply files that are optimized for sheetfed offset printing with a dot gain of 12 to 20%, operators may tweak other devices such as digital presses to mimic the dot gain behavior of offset presses.
What is CMYK in printing terms?
Here we explain what CMYK printing means
CMYK is an acronym. CMYK stands for four ink colors – Cyan, Magenta, Yellow and Black.
In offset and digital printing, the four ink colours, CMYK are applied to paper in successive layers. By overlapping these four ink colours a range of colours can be created. The combined visual effects of these four CMYK colors produce what we commonly know as Full Color Printing.
To understand it fully we will start with your computer screen. The colours you see displayed are RGB color. The RGB color model (made up of red, green and blue) RGB can only be viewed with natural or produced light, such as in the computer monitor. It is impossible to print RGB, This is where CMYK comes in. Because the RGB range of colour ‘gamut’ is far greater than CMYK not all of the printed colours can be reproduced.
When two RGB colors are mixed equally they produce the colors of the CMYK model, known as subtractive primaries. red and blue creates magenta (M) Green and blue creates cyan (C), and red and green creates yellow (Y).
Black is added to the model as a key. This is because it cannot be created with the 3 subtractive primaries.
What is CMYK in the printing process?
The four colour printing process uses four printing plates; one for cyan, one for magenta, one for yellow and one for black. When the colours are overlaid onto paper they create a visual image.
Digital Printing takes a different approach to printing each image. Instaed of ink they use toner, but still print in the CMYK format.The images are captured from a matrix of dots or pixels, this process is called digitising. The digitised image is then used to digitally control displacement of toner or exposure to electromagnetic energy to reproduce images. All professional digital printers today run on Postscript. This language was developed by Adobe and is used to produce the images, text and photographs. Postscript is a complex set of mathematical formulas also allow for algorithms to compress the data. It also gives a method of Calibration or Color Management Systems which helps to keep images looking at the same colour despite where they are view or printed.
What is CMYK in reprographics and graphic design?
Designers have to deal with the issue of viewing their work on screen in RGB, although their final printed piece will be in CMYK. Today, there are printers that can offer near RGB printing using green and orange to boost the colour gamut. Many years ago when we had better control over our apps we work in a closed system. Thats is we did not use ICC profiles to print to. But when you are printing to multiple devices each printer will be different and then this is where you may need greeter control. In today’s dumbed down apps this is all handled for you through Adobe Bridge.
Ask the printer
Before you start ask the printer for their specification sheet. It will give you all the information you require to send them the correct file first time.
It is a good idea to convert Digital files to CMYK before sending to printers, digital or litho. Because of this issue, it is important to use the CMYK Pantone system or similar for accurate colour when designing especially if you have critical brand colour to consider.
Pantone Swatches provide a designer and client with a printed example of what a colour will look like on paper. A selected swatch colour can then be chosen in Photoshop (or a similar program) to ensure the desired results. Even though the on-screen colour may not exactly match the swatch, you know what your final colour will look like. Alternatively ou can also specify a match proof from a printer, which is an digital example of your printed piece provided before the entire job is run. If the job is colour critical then the option of a press proof is the only guarantee of passing final colour. Proofing for Digital is easy, proofing for litho is far more complicated and expensive.
If you have any questions about CMYK colors or full colour printing just send us a email. We can offer guidance on just about any printing topic including What is CMYK and can simplify the task of buying printing for you.
CMYK Screen Angles & Resolution
In offset printing, the screen angle is at which the halftones of a separated color is outputted to a plate. To improve print quality and reduce moiré patterns, the screen for each colour is set at a different angle to each other. While the angles depend on how many colors are used and the preference of the press operator, typical CMYK process printing uses any of the following screen angles
Cyan 15º Magenta 75º Yellow 0º Black 45º
These angles can be switch around especially if you get screen clash.
Your photoshop files will be Okay at 300dpi at 100%. We recommend if you are using a press which prints at 200lpi then 350dpi should be your minimum. If anybody tells you different then they are idiots, because there is a vast difference in quality.
A final point NEVER USE JPEG’s
What is bleed in the print process?
Here we explain what is bleed? and why it is important
As a reprographics company this is one of the more common errors we handle on a daily basis. Trying to explain What is bleed? to someone you does not understand is difficult, so it is more than likely we have pointed you in this direction.
Bleed is a print term that refers to that part of the printing process that goes beyond the edge of the image area before trimming. In other words, it is the area to be trimmed off. The bleed is the part on each side of a document that gives the printer a small amount of space to account for movement of the paper, and design inconsistencies. Images, artwork and background colors can extend into this area. After trimming, it ensures that no unprinted edges occur in the final trimmed document.
There are three sizes to most print jobs.
The image size – this is the finished size of your job.
Print area – this is the area in which it is safe to go up to from the edge – generally a minimum 3mm smaller than image size on all sides. We recommend 4mm on business cards and 8/10mm on flyers.
Bleed size – this is the area in which the background ‘bleeds’ past the image size – generally 2/3mm larger than image size. 5mm/10mm on large format unless he print specially requests none.
If you have a background image, or a graphic which extends past your artwork then you will need bleed. If it is printed without bleed then you will have either white edges on your finished printed artwork, or the job will be trimmed undersize.
What is bleed in large format printing?
There are many web sites claiming that large format printing does not require bleed. As with all printing it is highly recommended that bleed and crop marks are applied to all single page documents. The exception is brochures and magazines where different rules apply. See below.
On posters up to A0 we recommend your PDF or artwork is supplied with 2/3mm bleed with crop marks.
On roller banners, banners and pop ups we recommend 5mm bleed with crop marks.
What is bleed in Magazines and Brochures?
The vast majority of printers will only accept PDF's for brochure and magazine work to their specifications. Always check with your printer before sending PDF's
Printing from an application. 3mm bleed needs to be applied to outer sides of the spread ON ALL PAGES.
Printing from PDF. 3mm bleed. Supply as single pages. Crop marks and registration marks are normally not required, check with your printer.
Creep in Magazines and Brochures?
When you fold multiple pages the outer sheets fall short of the centre pages. This is referred to as creep. We recommend that you do not bother with creep on anything less 48pp. 3mm bleed with naturally cover this. Anything over this when suppling PDFs you may wish to compensate. Both InDesign and Quark allow for this.
What is the difference between Digital and Litho printing?
A quick guide to the pros and cons of Digital and Litho Printing
What is the difference between Digital and Litho printing? Not as straight forward as you may think. Over the last decade Digital presses have made gigantic leaps forward in technology, performance, accuracy and quality, but Litho presses have done exactly the same.
Today’s Digital presses are more flexible and powerful than ever. They vary from A4 plus to oversize A2 and banner printer ( Longer lengths) They offer a comprable choice of stock, finishes, laminating and finishing options inline that is easily equal to Litho printing. Digital is great for short run printing, personalisation and meeting those deadlines.
Digital printing allows a job to go directly from a computer file direct to a printer or RIP (Raster image Processor), before being released to the printing press. This makes digital printing very quick to produce and extremely cost effective on short run work. Very much as you would send a file to your home printer. On demand printing is where digital scores heavily but it also has the option of variable data.
Variable data is where Digital outperforms litho. Personalised printing is where information can be added or changed to personalise letters, flyers, invitations, in fact virtually anything can be personalised. It can include a person’s name, address, product details, change images and graphics on each individual printed sheet. Personalising prints is easy and quickly done and set up costs are relatively small. Litho machines can also offer personalisation but normal this is applied on a second run.
Lithographic or ‘litho’ printing is a process is completely different. Your file is handled by a Pre Press or Reprographics department. It is checked and it is proofed, passed before sending to a RIP where it is digitised and a printing plate is produced. You need four plates to produce a full colour job, excluding any spot colours. The plates are then loaded onto a printing press where the plates are inked and this image transfer to a blanket before the paper.
Digital printing normally has a cost per click which does not vary and so has a limitation on its cost effectiveness. Litho printing is more expensive to set up but the cost reduces dramatically as the volume increases.
We are blessed to be in an age where printing has become very cheap. Prices have been drive down by cash rich, American and European Printer offering cut prices. These price cuts have seen the gap between the Digital and Litho prices narrow. Today’s modern printing presses have short run set ups, automatic plate changing which enable then to compete with Digital Print on shorter runs.
Flyers, Leaflets, Business Cards, Brochures and other marketing materials can be printed on a range of materials such as silk, gloss, uncoated, textured stocks, all with different weights, which is measured as gsm ‘Grams per Square Meter’. Between both litho and digital printing there is little difference between weight and quality of stock. For instance Digital is on 120gsm, Litho is on 130gsm, Digital, 160gsm, Litho 170gsm, small but virtually indistinguishable differences. Litho printing however produces better quality work when printing rough or heavily textured materials.
- No set up time or cost
- Instant proof of finished job
- Instant printing
- Runs virtually the same stock as litho
- Same finishing options
- Cost effective short runs
- Special spot colours and foil options
- Most printers require sign of before printing
- Plates have to be produced
- Expensive hard copy proofing
- Better quality
- Significantly lower cost on high volume
- Multiple spots and finishes can be applied inline
- Better for heavy and texture paper
There is no specific printing technique that is better than the other. It all depends on what you are printing, how many prints you need, and the material you’ll be printing on. They only factor where digital is king is speed and if you need personalisation.
Put simply for the vast majority Digital printing is cost effective when it comes to printing a few prints whilst litho printing works out cheaper if you are printing large quantities.
Litho printing is the better quality method when using textured paper and perhaps when the design requires a large colour block coverage. However, when you are printing on a more typical stock, the quality between the two printers isn’t noticeable. In fact many printers don’t even tell you if its litho or digital.
When it comes to choosing between digital and litho printing, you need to take these factors into consideration such as the quantity of the print, the material you want the print to be printed on, your budget and the design you are wanting to be printed as both printers have their pros and cons and certain aspects of the factors you need to consider.
If you need more information and you need advice please do not hesitate to call Digiprint, we are here to help.
Why you should always have a prepress proof if colour and brand are important
Prepress proofing is a tool for customer and printer to verify that a job to be printed job is accurate. This is why it is also know as Contract proofing. Prepress proofing or off-press proofing is a cost-effective way of providing a visual copy without the expense of creating a press proof. If errors are found during the printing process on press, correcting them can prove very costly to one or both parties involved.
A proof allows the customer to check every small detail for errors before the printing process is started. A prepress proof is for colour reference and accuracy, pagination, to ensure all the relevant elements are within the job. It often also serves as a final proof for the customer to check finer detail, brand colour are correct, images are high enough resolution. For the printer it is more about, bleed, crops, colour fidelity, make up, separations and that the job has or will separate correctly.
No large printer with a long print run, such as a magazine or brochure will print a job without some sort of proof being signed off by a customer. Once you have signed the printer will run to this proof. These days everything is handled by computer, including the printing presses. The chances of something being printed different to what you have passed is probably almost impossible. Every sheet is scanned and check for tolerance as it passes through the printing press and it will inform the operator if there is any variance.
What is Prepress proofing?
Prepress proofing, sometimes called off press proofing, is a cost effective way to get a visual copy of a printing order without having to go through the labor and expense of a physical press proof. This method is not always best though, and when certain requirements like exact colour matching are needed then a physical press proof may be the best choice in spite of the extra cost and work involved.
What are the they type of proofs available
Often referred to as a digital proof, a soft proof is a prepress proofing method that allows you to check a low resolution copy of the file. This file is often provided in a PDF format but can by JPEG or tiff file. Soft proofing simply allows you to check the final design elements to check that it has not corrupted or moved in any way.
Matchproof or chromlin proofing
Rarely used these days but still give the print an accurate guide to the colour expected. Cost if often the reason for not using these. Todays digital presses often can create a perfectly accepted final proof before litho printing and is far cheaper.
Hard copy digital proofing
As we have said may larger Lithographic printers have digital presses to ofter low run copies of magazine and brochures. Often you cannot distinguish between the two types of printing.
Wet proofs offers the highest level of quality for proofing any publication. They allow you to use the plates and stock that will be used on the final print run. Wet proofing is the only real way to proof items such as duotones or quadtones and is the best option for spot colour proofing. The individual proof is, however, hardly economically justifiable, however if the job is regular monthly magazine the settings are normally saved so this exercise need not be done again.
Normally a Press proof is for the customer to watch the print come of the press and sign off there and then. However it is possible to have a Press proof is a test print of the data directly on a printing press.
Which proofing method is best?
All of these proofing methods are fine for proofing purposes depending of what your requirements are.
Soft proofing is perfectly fine for smaller run jobs and is the most cost effective method available if he colours in the graphics do not have to be perfectly matched with 100% precision. Sometime it is worth paying a little extra to ensure that what lands on your desk is correct first time.
The limitations to all these proofing methods are the absence of Spot colour. Many of todays larger inkjet machines offer 11 colour RGB printing with can offer a great deal of accuracy of most of the Pantone range but not all. It is best to assume that the pantone colour will be printed correctly and the Prepress proof is simply an indication or guide. A Press proof of course will be accurate.
What should you check when prepress proofing?
When you are prepress proofing you need to look at everything, ensure that it matches your last proofs all the elements are their, the pages are in the correct order, folios and headers are where they should be. Experience here is vital, something like this is not for a beginer. Check, check and check again, remember your signature is the green light for printing.
Letterheads – legal requirements
What is the correct information to put on a company stationery?
First of all: All company’s including sole traders must be registered with HMRC. You can do that here.
Company stationery legal requirements are thankfully simple to implement but they do vary by the type of business you intend to run. Do not be tempted to omit anything, it has a habit to come back and bite.
Under the Companies Act 1985 your company must state its name. As it appears in its memorandum of association. In certain places and on its business stationery. Your company must also give certain information on all its business letters and order forms.
- Your full registered company name.
- The company registration number and place of registration.
- The company registered address and the address of its place of business, if different.
- There is no need to include the names of the directors on the letterhead for a limited company, but if you choose to name directors all directors must be named.
- Most letterheads also include a telephone, email, fax number, a url for the business’ website and an email address.
Certain businesses must also state the following on their business letters and order forms:
- For an investment company (as defined by section 266 of the Companies Act 1985) that it is such a company.
- For a company exempt from using the word ‘limited’ in its name, that it is a limited company.
- For a company with share capital, it is not necessary to state the share capital on stationary but if the company chooses to do so, the paid-up share capital rather than the authorised capital must be stated.
- Charitable companies whose name excludes the words ‘charity’ or ‘charitable’ must state the fact that it is a charity on its stationary.
- If you are a charity, you must also include the company’s charity number.
Where must the company name be displayed?
On which documents must the company name be shown?
- All the company’s business letters.
- All its notices and other official publications.
- All bills of exchange, promissory notes, endorsements, cheques and orders for money or goods purporting to besigned by, or on behalf of, the company.
- All its bills of parcels, invoices, receipts and letters of credit.
- All electronic data.
Must the company show any other details?
- Its place of registration and its registered number. The place of registration must be one of the following, as appropriate:
Company stationery legal requirements for companies registered in England and Wales:
- Registered in Cardiff
- Registered in England and Wales
- Registered in England
- Registered in London
- Registered in Wales
Company stationery legal requirements for companies registered in Scotland:
- Registered in Scotland
- Registered in Edinburgh
Must directors’ names be shown?
Must anything else be shown?
- For an investment company (as defined by section 266 of the Companies Act 1985), that it is such a company
- For a company exempt from using the word ‘limited’ in its name, the fact that it is a limited company.
- For a company with share capital, it is not necessary to state the share capital on stationery but, if the company chooses to do so, it must state its paid-up share capital, not its authorised capital.
Companies registered in the UK are now required to list their company registration number, place of registration, and registered office address on their company website.
Companies registered in the UK are now required to list their company registration number, place of registration, and registered office address in email footers.
Are there special rules for charitable companies?
You must include your charity number on all documentation
Do the rules apply to overseas companies?
Final Note: All information on all company stationery must be at a point size that is readable, if you make it so small it is difficult to read with the naked eye then it will be deemed as illegal.
First drafted 2009/2014. Updated June 2020
Taking care of your graphic panels
Great tips of how to look after your printed graphic panels
Taking care of your graphic panels | Pop ups
- Always roll up with the printed image on the outside. If you don’t the laminated and printed layers could split apart causing ‘bubbles’ or the lamination to split
- This is extremely important for Pop-up panels with magnetic tape fitted to the reverse. Rolling them up incorrectly with the image on the inside will stretch the mag tape and header and may fall off when unrolled.
- Always roll popup stand prints individually and place inside each other one by one in the case. Do not try to roll all of them up together at once.
- Laminated reinforced PVC banners. Rolling them up incorrectly with the image on the inside will stretch the overlaminate causing bubbles and creasing.
- Do not leave prints rolled up, or in a tube for anything other than short periods of time as they may permanently curl. Leave either flat, hung up on a wall, or very loosely rolled and stood upright.
- Pop-up carry cases are specifically designed for this so are OK.
- Always handle carefully and avoid creasing, kinking the prints. This type of damage cannot be repaired.
- Clean with a little water and washing up liquid, if that fails try with a little lighter fluid or glass cleaner on a soft clean cloth.
Taking care of your graphic panels | Rigid Board Mounted Prints
- Take extreme care with the edges and corners of mounted prints, especially lightweight foamboard as it damages easily.
- Do not put any pressure on the front of any rigid prints and avoid sharp objects.
- Please be aware, dents cannot be removed once made.
- Store flat if possible to avoid bending.
Taking care of your graphic panels | All Prints
- Roll up in direction of curl, normally with the image on inside.
- Protect your investment with tube or box.
- Do not leave prints rolled up, or in a tube for anything other than short periods of time as they may permanently curl. Leave either flat, hung up on a wall, or very loosely rolled and stood upright.
- Avoid any exposure to moisture, especially at the edges of the prints unless they are encapsulated and sealed. We can produce weather resistant prints using special inks and materials if required.
- Finger marks on the front can be removed with a little lighter fluid or glass cleaner on a soft clean cloth, but avoid anything which may scratch the surface – this only applies to gloss or matt laminated prints.
Taking care of your graphic panels | Cases
- Do not use abrasive cleaner on the surface, scuff marks should only be cleaned off with a little water and washing up liquid.
- A high vacuum will tidy up the inside. Any stains should be carefully remove with soapy water and allowed to fully dry before closing the case.
Hits v Vists
The difference between hits and visits. We explain here what is the difference between hits and visits.
Many company owners boost of the number of ‘hits’ they have received. It is often quoted as this is the largest number in the stats they read. Unfortunely it is also the most inaccurate and misleading. We explain here what is the difference between hits and visits.
Web states are a imprecise science that have many factors that affect the real numbers. Real numbers are extremely difficult to pin down. No two analitic devices will ever give the same conclusion on the same web site. So just what is the difference between a Hit and a Visit?
A “hit” is not a visitor to the web site, but a hit on the web server. A hit on the web server includes all the graphics on that page – pictures, java applet, the html file, etc. So, if a site has 30 small graphics on the page,
every visit to the site registers as 31 hits on the server (30 graphics plus the html file). As you can see this every visit will give you 31 hits, 2 visits 62 hits etc.
The number of hits to a web site is therefore irrelevant and to some extent pointless. What we need to know are the number of visitors to our site. More importantly we want to know are the number of unique visitors. This information is far more useful. Knowing how many people have visited, how many pages they looked at, start- and end-pages of each visit can be especially interesting because they emphasise what the visitors were looking for and what they did or did not find. Knowing where visitors spend their time on your site can help you improve the effectiveness of content or advertising or can indicate problems.
Hits v Visits
Visits represent the number of times your website had someone access it. Visits are independent of the actual number of pages viewed, the length of time the person stayed on your site, and does NOT represent the total number of unique visitors.
This number, often used by companies to tout the popularity of their website, represents the number of ‘requests’ for web page elements your website fulfilled and is not a true representation of how popular your web site is.
Sometimes called visit by cookie. Unique visitors refers to the number of distinct individuals requesting pages from the website during a given period, regardless of how often they visit. The website can track this as unique by the IP address of the computer. The number of unique visits will be far less that visits because a unique visit is only tracked if cookies are enabled on the visitors computer
Viewed per visit
This is also called Impression. Shows how sticky/interesting your website is. Each time a visitor views a page, this number is increased. Its important to note that this number is not limited only to unique visitors, but by all visits – including return visitors.
There may be better ways to measure web site performance. Using Cookies and other technology you give a more accurate figures. Possibly can also try subscriptions to your newsletter, number of signs up, number of sales, or bookmarks, number of emails you receive from the site or the number of guest book sign ups – problem is collation.
It is also very impotent to remember that not every page view is an actual read by a human being. Most page hits are from search engine spiders, email harvesters, page change checkers, and other automated services. These also add to the distortion.