The advantage of using Adobe RGB or ProPhoto RGB is that the larger  
colorspace allows more editing capability without clipping,  
preserving the integrity of the image data. With sRGB, you can  
rapidly lose data in doing simple curves and other tonal  
manipulations. These losses add up in successive edits. For the  
greatest possible editing flexibility, set your RAW output  
quantization to [EMAIL PROTECTED] and ProPhoto RGB colorspace.

Printers and screens don't have that much gamut to work with so a  
translation must be made to the appropriate colorspace for those  
output devices. Photoshop uses the monitor profile to translate from  
the colorspace of the data to the screen for editing purposes. You  
can see clipping when it occurs as you edit in the histogram, not on  
the screen.

When you print, to obtain the truest match to what you see on your  
screen with Photoshop you must print using a color managed workflow.  
You tell Photoshop to drive the printer and control color management,  
pick the correct match in Paper/Ink profiles for your specific  
printer model, inkset and paper, and Photoshop will translate the  
image data to that output device using the intent you specify. The  
intents that work best for photographic work are Perceptual or  
Relative Colormetric: they produce the least amount of data loss and  
the closest match to the screen rendering. The only way to know how  
they differ with a given image, far as I am concerned, is to test  
print using each of them and see how the translation works for that  
image. In this printing workflow, you must also have the ability to  
turn OFF the color management at the printer driver level otherwise  
you will be translating the color metrics twice with unpredictable  
results.

If your printer driver does not support turning off color management,  
the best results I've seen are to do a colorspace conversion to sRGB  
and then 16bit to 8bit reduction up front, to most closely simulate  
what the output device will image the data as, and then print using  
the "Let Printer Manage colors" so that the printer driver is  
accepting a known baseline color gamut in the data you're sending it.  
You can then use the driver's controls to manipulate the output  
rendering to your taste.

I find the color managed print workflow to be much more consistent  
and repeatable, presuming good monitor calibration/profiling, proper  
set up of Photoshop's color management settings, and good quality  
paper/ink profiles for a given printer and inkset. However, the  
bottom line in print quality is always dependent upon what works best  
for the equipment and configuration for you ... Once you come to a  
setup and workflow that works, you save yourself a lot of headaches  
and waste by standardizing on it and working with it, regardless of  
theoretical considerations.

Godfrey



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
>

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