Colour Management page 2
Can't you just use Colour Controls?
At first I thought I might be able to use the printer driver's colour sliders to correct the colour cast caused by using Lyson inks instead of Epson ones:
It doesn't work. The greyscale below is from the top part of the printer test chart printed using the settings above:
The very light grey is clearly yellow. But reducing the amount of additional yellow on the colour slider would make the blue cast on the darker greys worse. There is no way of curing the blue cast without making the yellow worse. In other words, the greyscale doesn't have one colour cast, it has a different colour cast for each shade of grey! Therefore we need something more sophisticated than the colour sliders to correct it. We need printer profiles.
Where do I get profiles?
Your "working colour space" is inside your computer, in a purely digital world. So you can choose your own working colour space and then forget about it. Even this has potential pitfalls, however. If you choose "sRGB", which is often the default setting, it works OK for the web but your print quality may suffer! The general consensus seems to be that the best setting is Adobe RGB 1998. For full details of how to set up Photoshop etc, see Ian Lyons' comprehensive Computer Darkroom website here
For the Scanner, Monitor and Printer, you essentially have three options for getting profiles:
1) get ready made profiles (either supplied with the hardware or downloaded from the web etc);
2) get custom made profiles from a specialist bureau; or
3) make your own.
The problem with ready made profiles is that there might not be a profile available for the ink and paper combination you are using. Even if there is a profile for the BRAND of printer, ink and paper you are using, it will not have been made for your ACTUAL printer, paper and ink. Just as photographic paper varies from batch to batch, so does inkjet paper, especially the glossy ones. And even the actual printer you have will change as it ages. The same is true of monitors and scanners. Monitors need to be re-profiled every few months as the phosphors age!
Making your own profiles can be costly, but there are one or two reasonably priced software packages for creating profiles. One of these is WIZIwyg, which is reviewed here. You can download it now and make a profile for your monitor.
I have very barely scratched the surface of colour management and profiling. I have found a number of articles on the web which I found very helpful:
James King of Adobe Systems has written a clear and readable explanation of the purpose of colour management entitled Why Colour Management?
Lyson's technical support page has a useful document entitled "Colour Management 2002" which explains the basics in much more detail than I have gone into.
Jonathan Sachs has also written a very clear and comprehensive tutorial on colour management which specifically relates to the Picture Window software (an alternative to Photoshop) but is useful for users of other software as it explains all the concepts.
There is a website called Accurate Image Manipulation for Desktop Publishing which contains over 200 pages of detailed explanation for the hardcore colour management junkie!
A good overview with links to lots of other useful resources is Norman Koren's page on colour management.