Red and yellow and pink and green . . . .

All the colours of a rainbow, all over our screens and on printed media everywhere we look, but getting it the mode right is a bit more complicated.

As a follow on from my pixel blog from a couple of weeks ago, the next thing to explain about images and print versus web is the way the colours work.

There are various ways that computers use to identify colours for different purposes, which I am sure many of you have seen – and possibly found confusing – when working with software colour palettes.
What with Hex values and Lab colour and pantones and the like, it can be hard to know what to choose.

Well to keep it simple for the moment, lets just go back to our pixelated photographic image. Whatever palette you use to create your colours, there are two main file formats, one for viewing on screen, and one for printing with ink.

If you know anything about theatre and light, you will know that when you shine a red, a green and a blue light together, it creates white. ( I am 99% sure of this – but not an expert), however, the following quote demonstrates the principle about the colours needed for any image that is to be portrayed via light – and that includes a computer screen and the internet.

“Blending the three primaries: Red, green, and blue, in washing fixtures such as the border, strip, or wide angle Par  allows the light artist to create virtually every colour the eye can see through the magic of colour synthesis—as illustrated by the RGB pixels of any TV screen.”

And of course a digital photograph. And that is why all digital photographs are saved by default as RGB images. (Red, Green Blue)

So we are now left with the second colour option, if we need to print our photograph with ink, in a newspaper, on a business card, on a flyer, banner etc etc etc.

To refer to the same language above, the primaries of print, which allow the printer to create virtually every colour . . . . are cyan, magenta, yellow and black. (otherwise known as CMYK – and just to be confusing the K is the black – which stands for Key.

(If you want to read more about the whys and wherefores on this then have a look at this.
Incidentally, I also came across this free photo editing software on the same page. ( I am not endorsing it but it might be worth a look if you don’t have anything else.)

Most of you will have some kind of home printer, and therefore will be familiar with the colour and black ink cartridges that you use. And this is exactly that principle.

And if you look closely in the margins of your daily newspaper, somethings you can see the coloured blocks of the individual inks, that are there as a kind of test that the inks are printing accurately.

Now while your desktop printer can do a pretty good job whatever kind of file you throw at it, you will get a slightly better result if you convert your photos to CMYK. Although it will depend on the quality of your printer, the resolution you are printing at and how good your eyes are – so don’t sweat it for your holiday snapshots.

However, if you are sending that top notch image to an external printer, particularly the online automated printer – then you do need to convert  your files to cmyk. (there is no guarantee that all photo editing software will be able to easily do this – photoshop does it really easily, but I could not manage it in gimp).
I did find this link but again I cannot endorse it (

The purpose of this weeks blog was to explain the difference, but as every day is a school day, I seen to have learned that for quite a few people, this simple conversion, could be a very stressful and time consuming process.

It really is a 30 second job for anyone with photoshop, so if you know someone, ask them.

But I am can provide a photo conversion service if you need that too.
And like most designers and printers, I will convert your photos for free, whilst handling the rest of your design and print.

Further reading (again I am not endorsing this company – but their article explains really well the need to convert your files)

Happy reading


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