I am trying to understand the use of ICC colour profiles in colour management.
My understanding is that any device that can record (camera) or present (monitor, inkjet printer, offset printer) has a colour profile describing its gamut under specified conditions. If you are doing colour work on a computer (including graphics in publications, retouching or correcting graphics, etc.) then you need to associate each input device (camera, scanner) and output device (monitor, inkjet printer) with its manufacturer supplied profile or, in fanatical cases, a profile specially calibrated for the device using suitable input and output targets, colorimeters, etc. Colour when stored in files by a camera, scanner or software program is actually in a hue-invariant model such as L*a*b*, and are transformed into a particular device colour space when moved to/recorded by/presented by that device from another. So far, so good. But what I do not understand is when programs such as Photoshop, Scribus, or InDesign allow you to choose particular profiles to use. Is this simply to provide a preview of how colours will look on a particular output device (offset, inkjet), to detect out-of-gamut colours, or are colours actually modified in some way when they are saved to disk by the program? If the latter and colours are actually translated within the program (Photoshop, etc.), won't they be distorted on the output device when its colour profile is applied again by the colour management system (CMS) to colours that have already been translated? A sort of colour double-counting if you will? If you are producing a PDF for a particular combination of printing process, CMYK inks, and paper, does, say, a printing profile such as SWOP applied to the PDF mean that the PDF file is merely a surrogate for the printing press and that no further profile is applied when the plates are burned? Any advice from those more knowledgeable than me is greatly appreciated. Regards, Hedley -- Hedley Finger 28 Regent Street Camberwell VIC 3124 Australia Tel. +61 3 9809 1229 Fax. (call phone first) Mob. (cell) +61 412 461 558 Email. "Hedley Finger" <hfinger at handholding.com.au>
