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Author Topic: Soft Proofing by the #s  (Read 2625 times)

E Slagle

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Soft Proofing by the #s
« on: September 03, 2008, 10:36:13 AM »

Due to my very average monitor (it's all I can afford at this time) I'm having difficulty visually soft-proofing some standard colors; specifically bright mid-day blue sky.

All color management aspects are tightly controlled (including high quality profiles and calibrated monitor) but still I'm having a challenging time printing a snappy sky...so rather than relying on my monitor I would like to soft proof by the numbers.

Problem, I can't find any Adobe or ProPhoto RGB #s for the colors of interest.

Pantone's Cerulean Blue seems appropriate but the RGB #s don't specify a color space (assuming sRGB):

http://www.pantone.com/pages/Pantone/panto...?pg=20194&ca=10

Help? Suggestions?

Eric
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Czornyj

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Soft Proofing by the #s
« Reply #1 on: September 03, 2008, 01:20:18 PM »

Quote
Due to my very average monitor (it's all I can afford at this time) I'm having difficulty visually soft-proofing some standard colors; specifically bright mid-day blue sky.

All color management aspects are tightly controlled (including high quality profiles and calibrated monitor) but still I'm having a challenging time printing a snappy sky...so rather than relying on my monitor I would like to soft proof by the numbers.

Problem, I can't find any Adobe or ProPhoto RGB #s for the colors of interest.

Pantone's Cerulean Blue seems appropriate but the RGB #s don't specify a color space (assuming sRGB):

http://www.pantone.com/pages/Pantone/panto...?pg=20194&ca=10

Help? Suggestions?

Eric
[a href=\"index.php?act=findpost&pid=219165\"][{POST_SNAPBACK}][/a]

You should find L*a*b values of that color, then PS will calculate RGB values for any editing space. It might be a problem then, that when you're printing the image, you'll probably use perceptual rendering, that compress bigger gamut of editing space into the smaller gamut of the printer - it may cause some colorimetric errors. If it will happen, you may try to use relative colorimetric rendering instead.

Mark D Segal

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Soft Proofing by the #s
« Reply #2 on: September 03, 2008, 05:26:37 PM »

Skies are difficult because they change colour according to the time of day and all times according to distance upward from the horizon. I've gotten natural looking results for a daylight sky valid from about 10 in the morning till 3 in the afternoon usinf Lab values of 75 -5 -24 for the bright portion and 60 -5 -25 for the darker portion. To blend them smoothly, you want the brighter sky closer to the horizon and the deeper tone further away. Put them both on separate layers, add a layer mask and use a black and white gradient on the layer mask to blend them gradually the one into the other so that it looks like a natural progression.
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Mark D Segal (formerly MarkDS)
Author: "Scanning Workflows with SilverFast 8....." http://www.luminous-landscape.com/reviews/film/scanning_workflows_with_silverfast_8.shtml

Peter_DL

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Soft Proofing by the #s
« Reply #3 on: September 03, 2008, 07:36:00 PM »

Quote
Problem, I can't find any Adobe or ProPhoto RGB #s for the colors of interest.

Pantone's Cerulean Blue seems appropriate but the RGB #s don't specify a color space (assuming sRGB):

http://www.pantone.com/pages/Pantone/panto...?pg=20194&ca=10
[a href=\"index.php?act=findpost&pid=219165\"][{POST_SNAPBACK}][/a]
Yes, it's sRGB 155, 196, 226 = HTML code # 9BC4E2.
You can check this in Photoshop (see color picker dialog box).
Interestingly, the Lab colors suggested by Mark are somewhat similar and also seem to be within the reach of sRGB.
Just convert to Adobe RGB or ProPhoto if you're looking for respective RGB numbers for reference.

sRGB 155, 196, 226
Adobe RGB 167, 195, 224
ProPhoto RGB 166, 180, 214
Lab 77, -9, -20

Peter

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« Last Edit: September 03, 2008, 07:52:40 PM by DPL »
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