By: Erik Vlietinck
Thu, November 01, 2007 - 5:13:00

http://www.dtpstudio.de
Score:

When I reviewed Genopal Pro the other day, my colleague Henk Gianotten pointed me to a software that he said I should definitely review. It was ColourAtlas 3.0, a German colour tool that can compare colours and create harmonies. When I saw the application’s interface I wasn’t too impressed, to be honest. Wen I first ran the application, the feeling remained until I started to explore more deeply into the program. After half an hour, I was more than impressed. I was completely convinced.

Here is a developer who knows colour and why people use colour comparison and colour harmony creation tools. Graphic designers, architects, layout designers, and basically everybody who has to take into consideration some form of colour management workflow --currently only excluding web designers-- can’t do much with Genopal or Color Schemer Studio. The reason is that those programs don’t tell you which colour space or system you’re working with. ColourAtlas 3.0 does, and t does a lot more.

What can ColourAtlas 3.0 do for people who deal with colour professionally? The answer is a list of things:

• It can show you how you can print a RAL colour as exact as possible.
• It can show you how a specific colour tone in RGB will look like in colour offset print
• It will create a series of colours that comply with complementary harmony rules and have specific lightness and saturation variation

The crux concept in ColourAtlas is “exactitude”. A digital colour nor a colour used in real-world industries, exists in a vacuum. There are numerous colour systems. Probably the best known and most universal is Pantone, but in Europe at least, there are hundreds of systems, such as RAL (e.g. for office equipment). All these systems contain a limited range of colours because the material used to create them (paint, ink and other colour media) can’t represent all the colours on the CIELab colour wheel.

ColourAtlas Uses Its Own, Internal and Accurate Conversion Engine

Digital ColourAtlas combines a couple of hundred of these systems with algorithms that allow you to compare colours between RGB, CMYK and one of these systems, and between multiple systems. Such comparisons are quite useful for creating catalogues, but also to convert colour values from one system to another.

Colour harmonies are supported by Digital ColourAtlas based on CIELab, i.e. accurate to perception. Now my first thought when using Digital ColourAtlas was that any ICC based system can do what ColourAtlas does, minus the colour systems aspect. I thought about Photoshop’s ICC conversion capabilities. Alas, the Digital ColourAtlas’ Help file quickly made it clear to me that ICC conversions aren’t going to cut it when accuracy and exactitude are what you’re aiming for.

The developers experimented and found that ICC conversion is good enough for converting image files for printing or the web, but when a RAL colour needs to be converted into CMYK, they found accuracy was lacking. The explanation states: “This primarily has to do with the fact that, as a rule, a high quality ICC profile accesses 928 support points (max. 1465 in the FOGRA profiles) for the entire colour space. These support points are converted sensibly – but in between approximation calculations take place. In contrast a normal CMYK colour value book shows that the available colour space is measured out in 10% steps, there are approximately 14,000 CMYK colour fields in the original. It seems clear that the accuracy of the colour matching using the colour value book must be higher than when using the colour value conversion.”

And the explanation continues: “There are indeed many options available for the approximation calculations (the so called “rendering intents”: “colorimetric”; “absolute/relative”; “saturation” and so on) but they remain approximation calculations that are inexact matches to the original. The accuracy of the ICC profile conversion is not sufficient for our purposes.”

Colours The Way Of Colour Management

The explanation in the Help file convinced me of one thing: these chaps know what they’re talking about, and they aren’t afraid of telling you how they get their results. Digital ColourAtlas 3.0 therefore isn’t just a fancy colour harmony creator. It’s much more, and it serves higher level purposes.

Now, working with Digital ColourAtlas isn’t exactly fun. Contrary to programs such as Genopal Pro, it’s even a bit tedious, until you get used to the rather aged interface. But as you get used to it, you soon start realising that the eye candy of the competition isn’t worth a great deal outside web design, where colour is currently not much more than what each user’s monitor will make of it.

So, what does ColourAtlas allow you to do? Well, you can use it to compare colours, in all directions. This means you can enter a RGB value and it will give you back the corresponding CMYK value with a deltaE (deltaE 2000) value as quality marker. Instead of converting to CMYK, you can also use CIELab values, system colours, RGB Printer colours, and more to compare with.

Colours can be entered in numbers, using the colour picker, and using a pipette. The latter enables you to take a picture, illustration or image and use a colour from that file as the basis for your colour comparison. An “Optimal Compare” feature enables you to use a calculated mean of the 3 closest RGB or CMYK fields. This mean value is weighed reverse proportionally to the deltaE error the colour fields show in relation to the comparison colour.