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CDTobie@aol.com wrote: >In a message dated 7/28/99 10:28:05 PM, firstname.lastname@example.org writes: > >>Now whether a Photoshop generated faux RGB profile will work worth a dang >>is a separate issue. A couple dozen patches in printing inks setup and >>dot >>gain curves is not at all the quality of hundreds of measured patches in >>a >>profiling software. But it has worked good enough for a lot of CMYK >>printers! > >This is a dubious assumption, the reason the few measurements in a Photoshop >profile make an acceptable press profile, is because they are a pretty good >description of what the press needs to know. This same data is not a >necessarily a very good representation of what an RGB process needs to know >for an accurate result...it might make a fair set of monitor curves, if the >CMY to RGB conversion was sufficient, but for quality RGB printing this would >not necessarily be enough. > Actually I wouldn't call it an assumption as much as a possibly non-parallel comparison. Howvever, I suspect you are uncategorically right for six color inkjet printers and for RGB profiles for film printers. But for four color printers I would categorize that "accurate" as probably a sliding scale. Before I got my profile software I could get an acceptable print on an Epson 3000 by converting to CMYK through a set of well measured Photoshop 5 printing inks colors. My only apparent problem was the lack of the true black curve when printing with StylusRIP. An RGB profile created this way (if one can be created this way) should behave with the same quality as the CMYK printing inks setup printing to StylusRIP -- though I have some qualms about how it would actually use the data in the conversion process. I suspect there are people with more CMYK skill than me who can create even better CMYK setup using the classic photoshop method who can go beyond my acceptable level. So I'm still a bit up in the air on this. But it brings up a good experiment -- I'll make a CMYK profile (500+ pacthes) in Color Synergy and a CMYK profile from a Photoshop classic set-up (8 color measurements and around 12 to 24 dot gain measurements -depending on how critical I want to be) and compare them in ColorSynergy's Gamut Viewer. Then run side by side prints to see if they are close. Actually I should have done that long ago rather than just assuming the 500+ patch CMYK profile or the 400+ patch RGB profile will be better and jumping into it. Somehow when PS 5 came along and messed with my mind on RGB setup I presumed I could fix everything if I just could make the right profile. I'll do a straight comparison this weekend! I'll assume my profile making skills have gotten to about the same level as my printing inks setup skills (not at the pro-level but at least competent). If I can't see the difference then I guess it is bye-bye to profiles (for four color work at least). If I can see a significant difference then I will struggle on with the extra measurements (and maybe an automatic measuring device) required for profiles. Need to simplify this somehow and I'm too much of a printer hacker to buy someones pre-made profiles (though I reconize the value of that service to non-hackers!). Dan Culbertson - Please: Stay on topic. Trim quoted messages. http://www.leben.com/lists for list instructions.
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