ARTWORK APPROVAL

Your printer does not print the colours as you see them on your monitor. The picture looks great on the monitor, but does not print true to the screen. This is absolutely true. You will never get a perfect match because the image on the screen and the image kicked out of your printer are two different beasts. Your screen's pixels are emitted light. Your printer simply can't print light. It uses dyes and pigments to replicate the colours.

Your monitor is composed of pixels and each pixel can display over 16 million colours. These colours are in what is called the RGB Gamut which, in very simple terms, is composed of all of the colours in light. Your printer can only reproduce around a few thousand colours thanks to the principle of absorption and reflection. Again, in simple terms, the pigments and dyes absorb the light colours that aren't used and reflect back to you the CMYK combination that closely approximates the actual colour. In all cases, the printed result is always a bit darker than the screen image. If you are new to this topic the above advice might seem a bit convoluted. The bottom line is the number of colours available in a particular Colour Space. Colour printers such as the Inkjet printer in your office have Cyan, Magenta, Yellow and Black cartridges. These are the traditional printing inks and the colour is made by combining those four colours. With ink, the number of colours that can be produced fall ,roughly, into a maximum of a couple thousand distinct colours. Images on a computer screen use a totally different colour space – RGB. The colours created are made with light. In broad terms the number of colours your computer monitor can display total about 16.7 million colours. (The actual number is 16,77,7216 which is 2 to the 24th power.)

If you draw a circle on a sheet of paper and put a black dot in the middle of that circle you will get a good idea of why colours change. The sheet of paper represents all of the colours – visible and invisible – infrared, ultraviolet, x-rays – known to modern man. That circle represents the RGB gamut and, if you draw another circle inside the RGB circle you have your CMYK gamut. If you move from a corner of that sheet of paper to the dot, in the middle that indicates how colour moves from invisible to a black hole which is the dot. The other thing you will notice is that as you move towards the dot, colours get darker. If you choose a red in the RGB colour space and move it to the CMYK colour space the red will darken. Thus RGB colours output as CMYK colors are pulled to their nearest CMYK equivalent which is always darker. So why does your printer output not match your screen? Simple. You can't print light.