It has been said that a digital image without a profile is like buying a burger from a dodgy burger van; is it beef, lamb, dog or horse? Who knows? A profile attached to an image is what gives it colour meaning within a digital workflow. Without a profile embedded or if a workflow is set to ignore profiles, colour management software will use a default ICC profile which could be wrong, and so cause an unwanted colour appearance change to the original file, even before any further colour conversions.
Often it is stated that profiles are removed or ignored because they are ‘wrong’. How this judgement is made is beyond me! If the image is RGB the profile should be used as the starting point within a colour managed workflow. If an RGB image has no ICC profile then some investigation or informed decision on the profile to assign will be needed.
The issues with CMYK images and profiles are a little more complex. Often they have no profile, so need to be viewed and judged, on screen, assigning the correct ICC profile for the chosen colour managed workflow. Areas such as total area coverage, grey component replace, etc need to be judged at this stage. For CMYK images with a profile, if it is the correct profile for your workflow, great. If not it may need conversion to the correct CMYK profile. Sometimes converting in Photoshop will be OK, however, often the use of devise link profiles and specialist colour server software will be needed to obtain the best CMYK to CMYK conversions. Again ignoring the CMYK profile in the original image will result in the colour management software, on the desktop or within CtP workflow, using a default CMYK profile, which will cause an uncontrolled colour conversion.
So I hope this brief blog, has at the very least, stopped you ignoring or removing profiles and will encourage you to increase your knowledge in this area.
My colour management courses can help in this area.
- Paul Sherfield who runs the consultancy is well known in the printing and pre-media industry as having considerable knowledge on digital workflows, with a special expertise on the business reasoning behind such systems.
He has installed some of the most successful digital pre-press and pre media systems in the UK. For 2 years he worked on a number of medium term projects before starting the consultancy in July 2000. Before this he was a partner in what became one of the leading pre-press/printing companies in London.
He is active in a number of industry groups including the BPIF Technical Standards Committee, ISO TC 130 printing standards committees and is chair of the BPIF steering group for ISO 12647/2 UK certification, He is a regular speaker at seminars and conferences.