Luminous Landscape Forum
Raw & Post Processing, Printing => Colour Management => Topic started by: probep on January 22, 2010, 09:37:46 pm
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Are there the standard or the common accepted methods for evaluating the accuracy of a "RGB-"printer profile? Something like Ugra/Fogra Media Wedge CMYK V3.0?
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Are there the standard or the common accepted methods for evaluating the accuracy of a "RGB-"printer profile? Something like Ugra/Fogra Media Wedge CMYK V3.0?
Great question. Short answer is no. Since CMYK proofing standards are based upon the simulation of an actual device(offset litho press), there is no comparable model when talking about RGB devices. Most of the synthetic RGB working color spaces are well outside the gamut of most printers so we cant expect the printer to fully recreate the gamut of the RGB profile. That said we can monitor and evaluate the gamut of a particular printer and the accuracy of the colors that it can reproduce. You could convert the media wedge to RGB(something with a D50 illuminate) and then print it using absolute colormetic rendering and evaluate the results. Since the CMYK patch set is much smaller than the potential gamut of most printers it's really only going to give you a snapshot of some of some of the interior colors. That said.... if you wait a few months there should be a new product on the market that should do exactly what you are looking for.
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if you wait a few months there should be a new product on the market that should do exactly what you are looking for.
Very interesting! Can you elaborate, please?
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Are there the standard or the common accepted methods for evaluating the accuracy of a "RGB-"printer profile? Something like Ugra/Fogra Media Wedge CMYK V3.0?
Depends on exactly what you're asking....the fact that it's an RGB (driver-based?) printer profile doesn't prevent you from making the same type of evaluations we might use with CMYK-based RIPs.
So...if you're asking whether you can evaluate the accuracy of your RGB profile against colorimetric data, absolutely you can.
But if you're asking whether you can evaluate the accuracy of your profile against an RGB working space profile such as ProPhoto, AdobeRGB or sRGB, you CAN but with some huge caveats. Like "Mussi_Spectraflow" already alluded to, you could take, say, AdobeRGB and convert it to colorimetric/L*a*b* data, print the result and then measure the print and compare it back to the colorimetric data. What you're likely to find however are very large delta e (differences) values that have more to do with the *gamut* of your printer/paper combination than actual *accuracy*. The best approach would be to start with a set of colorimetric data that are known to be in-gamut for your device (converting from AdobeRGB to your printerRGB profile and then back to L*a*b* would be one approach). Once you have known in-gamut values, you can more properly assess the accuracy of your printer profile....you can them simply print these values and directly measure the results on the print and compare them back to the original values. Naturally, you'll need several tools including a good spectrophotometer and software that allows you to compare two sets of colorimetric data.
Regards,
Terry Wyse