SubscribeJawdatt Mawassii, Vice President Sales and Business Development at GMG, explains why ICC profiles alone are not always enough for proofing applications.
Question: In the proofing environment ICC is seen as the accepted standard. GMG however has its own proprietary device link approach. Does GMG not support standards?
Jawdatt Mawassii, Vice President Sales and Business Development at GMG.
Jawdatt Mawassii: First of all, GMG fully supports ICC. But ICC has significant disadvantages that we overcome with our device link approach. And by the way device links are part of the ICC specification but only very few manufacturers of profiling and color management tools support this.
Question: What are device link profiles?
Jawdatt Mawassii: A device link profile includes all relevant information for a specific paper, the proofer used and the ink used with the proofer. This profile is linked to a specific printing process with a specific class of paper and can action a perfect CMYK-to-CMYK color transformation so that the final print can be simulated with contract proof quality on an ink jet printer.
Question: What are the limitations of ICC?
Jawdatt Mawassii: There are many limitations, for example the handling of the black channel. As a rule, the use of ICC profiles in color space transformations do not lead to the best result, because the CMYK data of the target color space are computed via the CIELAB conversion color space. So this means that black generation properties – long (0-100%) or short black (e.g. 20-70%) – are lost in the LAB color space, since it is only a three-dimensional color space which doesn’t contain any information about black while the 4D color space CMYK the black information includes.
Consequently, under ICC conditions, the newly computed CMYK data leads to a different proofing or printing result producing artifacts in the vignette and non smooth effects. The GMG device link approach doesn’t have these problems, as it is a direct CMYK-to-CMYK color transformation based on GMG's 4D color management. In this context, the original and target values are computed directly in CMYK – without the detour via LAB – meaning that the properties of the black channel of the original data are retained in their exact proportions in the target CMYK color space. This ensures that the visual impression of the print remains identical, even after color transformation.
Question: Are there other limitations?
Jawdatt Mawassii: The main ones are: ICC tools use private tags that can’t be interpreted by all other tools; There is no standardized CMM (color management module); Dot gain is not taken into account; The ICC approach uses confusing rendering intents; The profiling is based solely on assumptions regarding the properties of the printing press and doesn’t take into account the real characteristics of the press; There is no standardized computation for profiling.
Most importantly there is no separation between calibration and profiling. Consequently new profiles have to be generated regularly if, for example, the temperature, atmospheric humidity, paper or inks change, or as the printer simply ages. With the GMG approach, recalibration is all that is necessary to obtain excellent results again.
Question: So the user has clear advantages with the device link approach of GMG?
Jawdatt Mawassii: Yes. For a user certain criteria are relevant. A contract proof has a legally binding character. It is quite often the case that a proof costing a few Euros is the basis for a print job worth 100,000 Euros and more. So color accuracy and repeatability are key. A user is not interested in philosophic discussion about ICC or device link approaches. Only the end result counts. In all international shootouts GMG proves time and time again that our solution is state of the art and achieves the best results.
Question: GMG software has the reputation to be very complicated. Is this the price a customer pays for high quality?
Jawdatt Mawassii: The answer is a clear no. With the introduction of our new version GMG ColorProof is much easier to use. Actually for all users working with ISO standard profiles – and these are approximately 90% of our customers – there is no color management software on the market that is easier to use. After the installation of the software and the calibration of the printer, typically done by the dealer, the user only puts the files he wants to proof into a hot folder and the GMG ColorProof software handles the rest automatically.
Plus with GMG ProofControl the user can control the accuracy of the proof. If the result doesn’t meet the ISO specification anymore, he only has to recalibrate the printer and automatically generates proofs again which meet the ISO specifications. There is no easier way to proof. It is not possible to achieve contract proof quality so easily and quickly with any other ICC based tool.