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Author Topic: ProPhoto RGB convert or use in CS2?  (Read 3902 times)
mikecookson
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« on: March 11, 2007, 07:38:32 AM »
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When switching from LR to CS2 there is a profile mismatch between the LR default of ProPhoto RGB and Adobe RGB, (which is my chosen colour space in CS2). Is it better to:

- use the embedded ProPhoto profile?
- switch to Adobe RGB?
- change the default in LR to Adobe RGB?
- or do something different - and if so what?

Many thanks

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michael
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« Reply #1 on: March 11, 2007, 08:03:20 AM »
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I would suggest keeping your images in the largest possible workspace until you're ready to print or committ them to some other output. Why throw away data if you don't have to?

So, change CS2 to ProPhoto.

Michael
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bjanes
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« Reply #2 on: March 11, 2007, 12:57:03 PM »
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When switching from LR to CS2 there is a profile mismatch between the LR default of ProPhoto RGB and Adobe RGB, (which is my chosen colour space in CS2). Is it better to:

- use the embedded ProPhoto profile?
- switch to Adobe RGB?
- change the default in LR to Adobe RGB?
- or do something different - and if so what?

Many thanks

Lightseeker
[{POST_SNAPBACK}][/a]

I agree entirely with Michael's response (would I dare do otherwise on his forum?) but would like to add another reason for not converting to aRGB: converting between two matrix based profiles (such as aRGB and ProPhotoRGB) is always colorimetric, and out of gamut colors are clipped; matrix profiles do not have lookup tables to remap out of gamut colors perceptually. When you print from ProPhotoRGB, you have the option of using perceptual rendering to remap out of gamut colors into the printer space. Unfortunately, there are problems with most perceptual rendering intents, but you can remap the out of gamut colors yourself. These matters are discussed in [a href=\"http://photoshopnews.com/2006/07/07/lightroom-podcast-episode-8-posted/]Lightroom Podcast 8[/url] as reported by Jeff Schewe.

Softproofing in Photoshop is helpful, but it can be limited by the monitor, with most reasonably priced monitors displaying little more than then the sRGB gamut. If you are interested in a print, it is helpful to compare the gamut of the monitor to that of the printer and gamut mapping software can be helpful. Many pros use Colorthink for this purpose, but it is expensive. I have started to use Gamutvision.

Here is a Gamutvision 3D plot of my SynchMaster 213T as compared to that of my Epson 2200 printer with Premium Luster paper. If this representation is accurate, the monitor can display everything that the printer can print, so softproofing should work reasonably well.

[attachment=2074:attachment]

Here is a map of an actual photo in ProPhotoRGB showing clipping that would occur with convesion to sRGB. The colored vectors show clipping of out of gamut colors in the conversion. The reds are severely clipped. Since aRGB and sRGB differ only in the green primary, the situation would be similar if the conversion were to aRGB.

[attachment=2075:attachment]

This final view shows clipping that occurs when printing using the Epson supplied profile with relative colorimetric and black point compensation. The reds can not be printed and are clipped to an amorphous blob on the paper. The problem is to edit the reds so that gradations are preserved. Perceptual rendering does not do the job in this case, and manual editing could be tried (the subject of another post).

[attachment=2076:attachment]

Comments the above analysis and how the editing might be done are welcome.

Bill
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rslv
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« Reply #3 on: March 11, 2007, 04:34:56 PM »
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- change the default in LR to Adobe RGB?

Is this even possible? I haven't been able to find the option.
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Ray
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« Reply #4 on: March 11, 2007, 08:27:59 PM »
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I agree entirely with Michael's response (would I dare do otherwise on his forum?)

Bill,
That's not fair! I'm sure Michael can tolerate a certain degree of 'difference of opinion'   .

I'm not into the technical minutiae as much as you are, but it makes sense that converting from a big spaced profile to a smaller one might result in out-of-gamut colors where there were none before.... but not the other way round.

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Softproofing in Photoshop is helpful, but it can be limited by the monitor, with most reasonably priced monitors displaying little more than then the sRGB gamut. If you are interested in a print, it is helpful to compare the gamut of the monitor to that of the printer and gamut mapping software can be helpful. Many pros use Colorthink for this purpose, but it is expensive. I have started to use Gamutvision.

It's interesting that your tests indicate that your monitor can display everything that your printer can print. These results seem to be in conflict with generally accepted wisdom, ie. only really expensive monitors can display the full gamut of ARGB; Ultrachrome inks on glossy and premium lustre paper can display colors outside the gamut of ARGB.

My own practical, empirical tests show that my Epson 7600 (of the same ilk as your 2200, is it not?) can print yellower yellows from a ProPhoto color space than from an ARGB color space. The maximum saturation of yellow from ARGB has a slight tinge of green which is quite noticeable when the yellows from the 2 color spaces are compared side by side. However, I can't remember to what degree these differences were apparent on my monitor before printing. I vaguely remember the differences were only apparent on the CMYK info pallette.
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bjanes
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« Reply #5 on: March 11, 2007, 09:51:27 PM »
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Bill,

My own practical, empirical tests show that my Epson 7600 (of the same ilk as your 2200, is it not?) can print yellower yellows from a ProPhoto color space than from an ARGB color space. The maximum saturation of yellow from ARGB has a slight tinge of green which is quite noticeable when the yellows from the 2 color spaces are compared side by side. However, I can't remember to what degree these differences were apparent on my monitor before printing. I vaguely remember the differences were only apparent on the CMYK info pallette.
[a href=\"index.php?act=findpost&pid=106151\"][{POST_SNAPBACK}][/a]

Ray,

When I viewed the gamuts of the monitor and printer before I put them up, I was a bit surprised, since from memory I recalled that the Epsons can print better greens and yellows than most monitors can display. I checked gamuts on the Drycreek.com interactive site for the Epson 2200 and a high end Eizo monitor and indeed that was the case. At L* of 50 or so, the gamut of the printer with these colors was considerably larger than that of the high end monitor, but the monitor reds were considerably better than those of the printer. I think that a screen shot might infringe copyrights, but you can check for yourself.

I was using the profile for my monitor (hardly high end) created by my Pantone Sypder-- it may be a bit optimistic . The profile does show that the printer is limited in the shadow tones by the DMax of the paper (about 2.0). In this case soft proofing could be misleading if the image contains colors that can't be displayed on the monitor but which can be printed.

Bill
« Last Edit: March 11, 2007, 09:58:27 PM by bjanes » Logged
mikecookson
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« Reply #6 on: March 12, 2007, 08:42:31 AM »
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Thanks for all the comments everyone.
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Ray
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« Reply #7 on: March 13, 2007, 04:14:10 AM »
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I was using the profile for my monitor (hardly high end) created by my Pantone Sypder-- it may be a bit optimistic . The profile does show that the printer is limited in the shadow tones by the DMax of the paper (about 2.0). In this case soft proofing could be misleading if the image contains colors that can't be displayed on the monitor but which can be printed.

[a href=\"index.php?act=findpost&pid=106161\"][{POST_SNAPBACK}][/a]


Bill,

I'm using a Sony CRT monitor calibrated with EyeOne Display 2. The detail I get in the shadows on Epson Premium Lustre, Ultrachrome inks, ProPhoto RGB and Bill Atkinson profile seems very close indeed to what I see on the monitor. I couldn't hope for better.

But nothing's perfect. There are sometimes very minor discrepancies in hue and saturation. For example, sometimes the reds do not look quite as saturated on the print as they are on my monitor.

I suppose it is axiomatic that for soft proofing to work really  accurately, the gamut of one's monitor must be equal to or wider than the gamut of the printer's output (in relation to a particular paper/ink/profile combination).
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damien
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« Reply #8 on: March 18, 2007, 10:48:41 AM »
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The big problem for me as a portrait shooter is I output on RA4 photographic paper. sRGB is all I output andall the lab want. I do allow myself the marginally bigger aRGB colour space to work in because I convert to CMYK occasionally for magazines. In Lightroom I could be way out of gamut using the vibrance, curves or saturation tools and not know because the histogram is displaying a far higher gamut. It's a real problem for me. Lightroom will let me tweak images that really can't be reproduced in print. aRGB is big enough a space for me and it's a shame it's not an option in Lightroom - just for the measuring tools would be fine.
Damien.
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Mark D Segal
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« Reply #9 on: March 24, 2007, 07:38:20 PM »
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Red can be very difficult to deal with especially on matte paper. The Epson 4000 and 4800 printers can beincapable of reproducing the richness of red visible in a quality monitor image and the clipping or compression that takes place converts the red to a dull marroon. This is not so much related to the choice of working space as it is to the gamut of the printers. It is never a surprise, because it shows in soft-proofing straight away. The problem can be mitigated but not eliminated by using a Selective Color Adjustment Layer, and for the colour Red, reducing Cyan a bit, increasing Yellow a bit and adjusting Black to taste. Over-doing these adjustments can wipe out detail in the troubled Red, so moderate adjustments are all that one should normally make.
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