The issue of colour - Colour matching explained

Colour matching for different printing applications is one of the key parts of the job that I do as a graphic designer or as a web designer. You may have things printed for many different application and you wonder why the colour can't be matched perfectly each time?

In this article I am going to try and explain how colour works, and why it can be quite a complicated issue to match your company colours correctly for every application.

Colour is effected by many things : whether it is on your screen, or on paper - is it on a sign banner, or car graphics, billboard or up in lights? Each application has its unique issues which are governed by the materials to be printed on, the type of ink used and if it has any protective coating like laminating etc.

Professional printing uses "CMYK" inks, which stands for "Cyan Magenta Yellow and Black" (Black is K). These four primary colours are mixed together to reproduce all colours. (Image on right : the CMY printing colours)

(Image courtesy of Wikipedia article : Subtractive color - click here)

For most printing applications we can also use a standard called the PANTONE spot colour matching system. This is a world wide established colour standard that we go by so that printers / designers can match your company colours - no matter where in the world you are getting the printing done. This is done by using a swatch book (just like paint samples) and colour codes known as PMS spot colours.

eg. A bright orange is PMS 021 and a nice red is a PMS 032.

Each spot colour in the PANTONE swatch book is assigned a number. Each colour has a very specific formula so that the printers can match that exact recipe to reproduce your colour. Every mix of the colour is slightly different as it is impossible to get it exactly the same, so colours will always vary from job to job / printer to printer. Link to the PANTONE website click here.

(Image on left : a PANTONE swatch book)

The other thing that can effect how the colour comes out is the paper stock or material it is printed on. You would be surprised how many shades of white there is out there! So, a printer doesn't just have to match the formula of the ink, they have to adjust it for the material it is printed on too. Matte or gloss laminating, printing on plastic etc. can also greatly effect how a colour looks.

For vehicle graphics and signage, the colour can be effected because you may need to use special UV resistant inks so they last outdoors - and often when you apply graphics to a car, the actual colour of the car can show through the vinyl sticker and effect the colour appearance too.

Colours will also come out differently when printed digitally or printed using an offset printer. Offset printing uses metail 'plates' which overlay each colour over the top to combine to make the colour - where digital printing colours are managed by a computer. Digital printing can either use inks or laser colour printing. Laser printing 'fuses' (melts together using heat) different colour 'toners' together to achieve different colours.

Web design and anything made for the screen is another issue all together because they are generated by light shining from your screen at different wavelengths. Web / screen / video colours are known as "additive" colours - because they combine red, green and blue (RGB) to make all colours. RGB white is actually a combination of the max of all three colours together. The type of screen, and how your colours are balanced can effect this. (Image on right : the RGB screen colours)

(Image courtesy of Wikipedia article : Additive Color - click here)

Printed colour is known as "subtractive" because when light bounces off a surface, the colour you see is actually subtracted from the wavelength of light, and absorbed into the material.

So, you can see that colour management is not an exact science and there are a lot of factors to keep in mind when trying to match everything to your exact company colours. It is impossible to reproduce your colours exactly. A good graphic designer and printer will be able to match with a 3-5% margin of error.

As a part of our service here at Medform, we look after this side of things for you to ensure your material is always reproduced as close as possible to the correct colour. Any questions, please contact me today or leave a comment here.

-- Heather Measday | graphics@medform.com.au