An excellent description of the issues, me thinks. Thanks much! -- Bruce
Friday, March 9, 2007, 7:38:15 AM, you wrote: GD> The advantage of using Adobe RGB or ProPhoto RGB is that the larger GD> colorspace allows more editing capability without clipping, GD> preserving the integrity of the image data. With sRGB, you can GD> rapidly lose data in doing simple curves and other tonal GD> manipulations. These losses add up in successive edits. For the GD> greatest possible editing flexibility, set your RAW output GD> quantization to [EMAIL PROTECTED] and ProPhoto RGB colorspace. GD> Printers and screens don't have that much gamut to work with so a GD> translation must be made to the appropriate colorspace for those GD> output devices. Photoshop uses the monitor profile to translate from GD> the colorspace of the data to the screen for editing purposes. You GD> can see clipping when it occurs as you edit in the histogram, not on GD> the screen. GD> When you print, to obtain the truest match to what you see on your GD> screen with Photoshop you must print using a color managed workflow. GD> You tell Photoshop to drive the printer and control color management, GD> pick the correct match in Paper/Ink profiles for your specific GD> printer model, inkset and paper, and Photoshop will translate the GD> image data to that output device using the intent you specify. The GD> intents that work best for photographic work are Perceptual or GD> Relative Colormetric: they produce the least amount of data loss and GD> the closest match to the screen rendering. The only way to know how GD> they differ with a given image, far as I am concerned, is to test GD> print using each of them and see how the translation works for that GD> image. In this printing workflow, you must also have the ability to GD> turn OFF the color management at the printer driver level otherwise GD> you will be translating the color metrics twice with unpredictable GD> results. GD> If your printer driver does not support turning off color management, GD> the best results I've seen are to do a colorspace conversion to sRGB GD> and then 16bit to 8bit reduction up front, to most closely simulate GD> what the output device will image the data as, and then print using GD> the "Let Printer Manage colors" so that the printer driver is GD> accepting a known baseline color gamut in the data you're sending it. GD> You can then use the driver's controls to manipulate the output GD> rendering to your taste. GD> I find the color managed print workflow to be much more consistent GD> and repeatable, presuming good monitor calibration/profiling, proper GD> set up of Photoshop's color management settings, and good quality GD> paper/ink profiles for a given printer and inkset. However, the GD> bottom line in print quality is always dependent upon what works best GD> for the equipment and configuration for you ... Once you come to a GD> setup and workflow that works, you save yourself a lot of headaches GD> and waste by standardizing on it and working with it, regardless of GD> theoretical considerations. GD> Godfrey GD> On Mar 9, 2007, at 6:59 AM, Markus Maurer wrote: >> Indeed sRGB seems to be the easiest way, if I change Photoshop to >> Adobe RGB >> or PhotoProRGB I get these washed out JPG savings no matter if I >> choose >> SFW or save as --> JPG. I wonder how much information gets lost in >> press >> print with sRGB, the tutorial I saw on the web is quite impressive >> and show >> a >> huge loss in color space with sRGB compared to Adobe RGB or even >> better >> PhotoProRGB. >> >> Has somebody with a high end printer ever tried the different color >> spaces >> on a printer, I wonder if I really have to choose PhotoProRGB for my >> calendar project to get rich and deep colors as promised >> >> Have a look at: >> http://www.luminous-landscape.com/tutorials/prophoto-rgb.shtml >> . >> But when I can't see all the colors on the monitor for proofing I'm >> a bit >> afraid of getting color cast and unprintable colors later as a nasty >> surprise. >> Decisions, decisions, I want more time to t a k e photographs >> instead ;-) >> >>> >>> When I worked in a lab using a Fuji processor, adobe RGB gave me a >>> terrible >>> blue cast. Switching to sRGB fixed the problem. This was with >>> the IstD >>> >>>> ..Experimenting with Adobe RGB, sRGB and ProPhotoRGB color space >>>> settings >>>> leaves me confused enough for today. Too much reading.... >>>> I will have to go out tomorrow for some close-ups, that little >>>> 18-55mm Kit >>>> lens will come handy for some first landscape test shots. >>>> >>>> http://www.mypage.bluewin.ch/solicom/leoleu1.jpg >> -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net
