Catton Print Artwork Guide

My Image

Hi, my name is Kat.

Those nice people at Catton Print have asked me to give you an insight into the dark art of the printer. Is it really a world shrouded in mystery and ritual? Well no, not really, but some of the terminology used can be a little confusing.

The aim of this page is to cut through the jargon and explain how to get the best from your chosen printer, while dispelling a few myths along the way.

We have also tried to include some information that we hope you will find useful.

Just click on the boxes for more info………

Common paper sizes
By designing your artwork to fit the paper sizes defined by the ISO 216 standard (more commonly known as ‘A’ series papers) you can minimise wastage and reduce costs.
  • A1 594 x 841 mm Posters - Printed on our Wide format inkjet
  • A2 420 x 594 mm Posters - Printed on our Wide format inkjet
  • A3 297 x 420 mm Posters - Printed digitally or litho
  • A4 297 x 210 mm Usual size for letterheads etc. - Printed digitally or litho
  • A5 210 x 148 mm Typical size for greetings cards, flyers, etc. - Printed digitally or litho
  • A6 148 x 105 mm Typical size for postcards - Printed digitally or litho
  • 85 x 55 mm Most common size for business cards
A note to users of Microsoft Word™ and other word processors:
The default page size for MS Word™ and many other word processing programs is set to“Letter” (for the US market). We strongly advise you to set this to A4 in the program’s preferences.
Printing methods
There are many different methods of printing, depending on the material being printed on and the intended purpose. At Catton Print we use 3 methods - Litho, Digital and Wide Format Inkjet.

Litho Printing
Also known as Lithographic or Offset Litho printing, this is the method most people probably think of as “traditional” printing. The image is produced on a printing plate. A roller in the print machine applies the ink to the plate. The ink sticks to the plate in the required areas and is then transferred via another roller to the paper.

Advantages:
  • Suitable for a wider range of cards and papers.
  • Cheaper for larger quantities.
  • Allows for exact colour matching, if required.
  • Extremely accurate positioning of image on the paper.
Disadvantages:
  • Not economically viable for short runs, due to the requirement of printing plates and machine set-up times.
  • Lead times can be longer than digital, due to set-up, and the requirement for ink to dry before finishing.

Digital Printing
Digital printing is a dry process where coloured toners are fused to the paper or card using heat. Massive improvements in technology mean that, for the majority people, the end result is now indistinguishable from litho printing.

Advantages:
  • Fast turnaround (depending on workload).
  • Minimal set-up costs make digital printing more economical for short runs.
  • More forgiving of lesser-quality artwork than litho.
Disadvantages:
  • Less precise colour matching than litho.
  • Lower positional accuracy (registration) than litho.
  • More restricted paper choice e.g. not suitable for very thick card or heavily textured papers.
  • Less economical than litho on longer print runs (larger quantities)

Inkjet Printing
For sizes above A3 we print using our wide format inket printer. Using only the manufacturer’s recommended materials, this is really only suitable for very small quantities due to the high cost of inks and paper.
Crop marks, bleed, etc.
What’s all this malarkey about crop marks, bleed, and the like?

Before we get into the ins and outs of these terms it may help to give a brief description of the printing/finishing process.

In most cases the paper used to print a job is larger than the finished size required, and then cut to size after printing.

Let us consider the following example:
My Image
My Image
If we were just printing and cutting one sheet of paper this would not pose any problems.
However, let us consider the effect of the small variations that can occur when multiple sheets are stacked for cutting with a guillotine (greatly magnified):
My Image
The examples above are not errors, but the unavoidable consequence of growth and/or shrinkage of the paper that can occur throughout the printing/drying stages (even metal expands and contracts with temperature changes). Now imagine these variations spread over a stack of maybe several hundred sheets of paper, and you can see that there is a need to take this into consideration when designing for print.
What is bleed, and why do I need it?
You will find that printers will always specify a recommended figure for bleed (usually 3mm). This means that any part of the artwork that needs to go right to the edge of the finished document, including any background colour, should extend 3mm past the finished size.

Example:
I want these invitations for my birthday party printed. Notice how the photo and green background go right to the edge of the finished invite.
My Image
The examples below show how they could look after cutting if I just sent the artwork at the exact finished size.
My Image
My Image
To avoid this I just extend the artwork beyond the finished size of the invite into the “bleed” area:
My Image
Alternatively, I could have avoided the need for bleed altogether by keeping everything well away from the edges of the paper:
My Image

TIP: It is always advisable to keep important elements such as text at least 3mm away from the edge of the finished size to allow for misalignment when cutting to finished size

How do I create bleed with my software?

All true desktop publishing programs will have a facility for specifying the bleed size, but what can you do if you are using a program like Microsoft Word™ or Adobe Photoshop™?

You can trick many programs into creating a bleed area simply by setting the page size to 3mm larger all round than the finished size of the job.

In the example below the finished (cut) size of the paper is to be 148 x 210mm (A5). The page size for producing the artwork is set to 148+3+3 = 154mm by 210+3+3 = 216mm.

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If using this method don’t forget that 3mm will be cut from each edge when you are designing your artwork.
Also, don’t forget to let your printer know what you have done, or he may cut your job to the wrong size.

I am supplying MS Word™ files with everything inside the margins. Do I need to worry about bleed?

No. Just supply the files, or even better, a PDF file from the Word Document. We will do the rest.

Crop marks
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Crop marks, also known as Trim Marks or Cut Marks, show the printer where you want the paper cut in relation to the artwork. In many cases you don’t have to worry about them, as the printer will add them before printing your job. For example, if you are supplying a simple document from a word processor, at the page size you require the finished job to be printed, with everything inside the margins, you can forget about them. Similarly, if your file is supplied with the same amount of bleed on all four sides (and you have told the printer what this is), the printer can add them.

However, if you are supplying your artwork with crop marks here are a few pointers to avoid unwanted marks on your finished prints.

If your software gives you the option to add crop marks all of the following will be handled for you automatically. However, if you are adding crop marks to your artwork manually there are a couple of things to bear in mind.

Keep your crop marks at least 2mm from the edges of the finished job when cut to size (see images below).

Finished size shown white, bleed area (shown blue)

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My Image
My Image

Make sure that the crop marks extend by the same distance on all four sides. This ensures that the centre of the document remains in the same position, making it easier for your printer to position it correctly.

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My Image

It’s all about the image….

It is not unusual for people to simply grab images from the internet for use in their printed documents. Quite apart from the copyright issues that may be involved, they are often disappointed with the end result. This section explains some of the problems associated with images, and how to avoid them.

Again, just click on the boxes for more info………

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Image types

Vector based images
These are produced by drawing programs such as Adobe Illustrator™, and contain instructions to the computer on how to draw the object (e.g. draw a circle and fill it in red). Vector based images are scaleable, and can be re-sized without losing any quality. Image files with the following extensions are usually, but not always, vectors - .ai .svg .eps

Bitmaps (also known as Raster images)
Images such as photographs, and anything created in a paint package, are made up of tiny blocks of colour, and degrade when enlarged. Image files with the following extensions are bitmaps - .bmp .jpg .jpeg .gif .tif .png

My Image
My Image
A few words about words

Text in your document is handled in much the same way as vector-based images i.e. it is fully scaleable without any loss of image quality, BUT it is dependent on the printer having the same font installed on his computer. Also, if you save your file as a bitmap the text becomes part of the image, and is therefor no longer scaleable and cannot be edited.

The importance of resolution

No, I’m not talking about those broken promises you make to yourself every new year’s eve. You already know that bitmap images are made up from thousands, or millions, of tiny coloured blocks (also known as pixels). Image resolution is the number of these blocks in an inch. This is usually expressed in terms of dpi (dots per inch).

The ideal resolution for printing is 300 dpi, whereas images designed for display on a screen, such as web pages, are usually created at just 72dpi. Images on the internet are also often saved in a poorer quality, compressed file format to keep the file size down, thus speeding up page loading.

There is a direct relationship between the size the image is printed at and the dpi. For example, if an image is printed at twice the original size the effective dpi is halved (a 1” square 300dpi image enlarged to 2” square becomes 150dpi). By the same token if an image is printed at half the original size the effective dpi is doubled (a 2” square 150dpi image reduced to 1” square becomes 300dpi).

The illustration below has the same photo of me at 3 different resolutions (dpi). In the top row they have been reproduced at sizes that give an effective 300 dpi. In the bottom row they have been kept at their original size and resolution:

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Note: on low resolution screens, such as phones, you may not notice any difference in the above images

The original and best

Simply increasing the size (or dpi) of an image in a package such as Photoshop™ does not improve the quality. The photograph below was reduced in size and saved. The new, smaller version was then enlarged back to the original size. See how the detail has all but disappeared!

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Wherever possible, always use the original image, or supply it to your printer so he can insert it for you. There is an old saying that you cannot make a silk purse out of a sow’s ear. Similarly, your printer cannot make a good print from a poor original.


Colour my world

One of the most misunderstood areas of preparing artwork for print, and one which can cause the most disappointment, is colour. In order to understand the reasons for this, it is worth taking a look at the differences in how your image is produced on a computer screen, compared with how it is applied to the paper.

My Image
Screen vs Paper

When working with full-colour images the image displayed on your computer screen is created by combining Red, Green and Blue light (RGB). To create the same image on the paper your printer will use Cyan, Magenta, Yellow and Black ink (CMYK).

Because the image on a computer screen is created using light images will often appear brighter on the screen than on the finished print, depending on your monitor settings. RGB can also display a greater range of colours than the CMYK process. Although the digital print process is more tolerant of RGB images it is still better to save your artwork using the CMYK colour mode if your software allows it.

Unless you are using an expensive, correctly calibrated, monitor you cannot rely on the colours on your screen being an accurate representation.

Black is black….. except when it isn’t

When working in CMYK, you may think that setting black (K) to 100% will be as black as black can be. Not so. Designers know (sometimes from past disappointing results) that simply using black on its own will produce a washed-out greyish black, more evident in litho printing that digital. The addition of Cyan, Magenta, and/or Yellow to the black will produce what is known as “Dense” black, or “Rich” black. Consider the examples below:

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The third example 3rd from the left is the default black in the photoshop colour palette. You may ask “Why not just use 100% of all four colours? Surely this would give the densest black”. In practice, you should aim to keep the total of all colours below 300% to avoid overloading the paper with ink.

Note: The differences in the rich black blocks above may not be visible, depending on the quality and settings of the display you are viewing this page on.


We hope this information has been useful to you. If you have any questions about preparing your artwork for submission to Catton Print, please don’t hesitate to contact us for further advice.