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Author Topic: Absolute Colorimetric? Who would have thought?  (Read 6818 times)
walter.sk
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« on: March 23, 2009, 10:09:58 PM »
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I have been printing on a Z3100 using HP Instant Dry Satin, and softproofing from Photoshop.  The paper is on the bluish side, and with color prints I have been able to tweak the softproofs and get very satisfactory matches between print and display.  I have been using Perceptual  or Relative Colorimetric intent, depending on the image.

I have had real trouble making black and white prints neutral, as I came to realize that the paper's blue cast is not even.  The shadows are bluer than the mid and higher tones, so trying to balance by adding yellows or oranges is more critical, requiring working on different levels separately.

Out of frustration, I tried Saturation and Absolute Colorimetric intents and much to my surprise, the Absolute Colorimetric worked like a charm, bringing the softproofed version of the image to look almost exactly like the original image.  With a very minor tweak to Curves, the image printed very well, looking as neutral as I would like.

Have I been missing something, or am I missing something now?  I have not read nor heard about using Abs Col in this way, but it seems to work.
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Damo77
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« Reply #1 on: March 24, 2009, 12:30:10 AM »
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Maybe I've been missing something - I thought Absolute Colorimetric was useful only for proofing ... ?  I can't think of any other purpose for it.
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Damien
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« Reply #2 on: March 24, 2009, 05:36:06 AM »
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I use it a lot especially for images with a strong graphical content such as coloured painted buildings and industrial features. It looks good on certain portraits too. I have requested it as a feature in one of Lightroom's rendering intents. Photo academics poo-poo the idea insisting that only Relative and Perceptual should be considered. But for a dynamic colour print as vivid as the monitor display Absolute Colormetric is the way to go.

John
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Damo77
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« Reply #3 on: March 24, 2009, 06:01:01 AM »
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Ok, now I'm even more confused.  John, I thought it was the Saturation intent that did what you describe.
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Damien
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« Reply #4 on: March 24, 2009, 08:00:35 AM »
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Quote from: walter.sk
Have I been missing something, or am I missing something now?  I have not read nor heard about using Abs Col in this way, but it seems to work.

If it works for you, great. However, Absolute Colorimetric is intended for proofing (make my Epson print look like my Contract Proof) and is identical to RelCol except it maps paper white to the output destination. When used for proofing, it will attempt to match the white of the paper on the proof which can be darker, warmer, cooler etc. Again, if it works fine but I suspect the coolness or color issue might be due to OBAs in the paper and how the paper profile was built/measured.
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Andrew Rodney
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walter.sk
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« Reply #5 on: March 24, 2009, 08:40:40 AM »
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Quote from: digitaldog
Again, if it works fine but I suspect the coolness or color issue might be due to OBAs in the paper and how the paper profile was built/measured.
I'm pretty sure that the blueness of the paper is the result of OBA's.  My paper profile was made on the Z3100 using the 918-patch target.

I have not had any difficulty getting neutral grays with other papers I have profiled:  Epson Enhanced Matte, Epson Premium Luster, HP Hahnemuhle Textured Fine Art Paper, among others.

My usual test print includes the Digital Dog file, parts of several of my own images, and a 10-patch grayscale I generated from CS3.  With the Z3100 home-made profiles for these papers I have always been stunned by the degree of neutrality shown in the grayscale part of the test prints, usually using Perceptual Intent.
« Last Edit: March 24, 2009, 08:42:19 AM by walter.sk » Logged
jmwscot
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« Reply #6 on: March 24, 2009, 09:21:07 AM »
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Quote from: Damo77
Ok, now I'm even more confused.  John, I thought it was the Saturation intent that did what you describe.
Damien, I understand what you are saying. Adobe describes the rendering Saturation as for charts and graphs where bright saturated colours are more important than accuracy. Absolute Colormetric leaves colours within the destination gamut unchanged and the colours outwith the gamut shifted to the closest reproducible colour. Relative Colormetric compares the white point of the destination with that of the source and shifts all colours accordingly.

You would expect from the descriptions for Saturation to give the more vivid colour. In practical terms I have found, using an Epson 3800 printing from Photoshop, Absolute Colormetric gives a more vivid reproduction of colours than any of the other renderings. In effect it looks like the monitor display without my normal soft proofing applied. I only use it for certain subjects but if you haven't tried printing using Absolute, give it a go. Your results, depending on your printer, may be different to mine.

Regards, John
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digitaldog
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« Reply #7 on: March 24, 2009, 10:35:34 AM »
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Like the perceptual intent, there's no standards in how one creates a Saturation rendering. While it is supposed to be appropriate for "business graphics", there's no reason it would or would not work on an image. Soft proof and decide.
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Andrew Rodney
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Mark D Segal
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« Reply #8 on: March 24, 2009, 06:07:50 PM »
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I very much support Andrew's comment here. I use it when I wish to give particular emphasis to certain very prominent colours in an image which has a strong "graphic" profile - but is of course still a real-world photograph. I also find it very useful for handling snow.
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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
bjanes
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« Reply #9 on: March 25, 2009, 07:53:22 AM »
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Quote from: digitaldog
Absolute Colorimetric...is identical to RelCol except it maps paper white to the output destination. When used for proofing, it will attempt to match the white of the paper on the proof which can be darker, warmer, cooler etc.

On initial reading of the above statement, I inferred the opposite of what actually is true. A quick reference to Color Management by Fraser, Murphy and Bunting, second edition, clarified the situation and I am posting the relevant text in the hope that it will avoid confusion by others.

Absolute colorimetric differs from relative colorimetric in that it doesn't map source white to destination white. Absolute colorimetric rendering from a source with a bluish white to a destination with yellowish white paper prints cyan ink in the white areas to simulate the white of the original.


Relative colorimetric...maps white in the source to white in the destination, so that white on the output is the white of the paper rather than the the white of the source space. The eye adapts to the white of the viewing medium.

Bill




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walter.sk
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« Reply #10 on: March 25, 2009, 08:46:24 AM »
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Quote from: bjanes
Absolute colorimetric differs from relative colorimetric in that it doesn't map source white to destination white. Absolute colorimetric rendering from a source with a bluish white to a destination with yellowish white paper prints cyan ink in the white areas to simulate the white of the original.

Bill
So if my RGB file with a grayscale image is neutral to start with and I print to a bluish paper using a decent profile for that paper, and the intent is Absolute Colorimetric, it will try to simulate the (neutral) white of the original?  Would that explain why the print (and soft proof) came out neutral, while soft proofing and printing with either RelCol or Perceptual were not as successful at neutralizing the blue?
« Last Edit: March 25, 2009, 08:47:29 AM by walter.sk » Logged
bjanes
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« Reply #11 on: March 25, 2009, 11:10:15 AM »
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Quote from: walter.sk
So if my RGB file with a grayscale image is neutral to start with and I print to a bluish paper using a decent profile for that paper, and the intent is Absolute Colorimetric, it will try to simulate the (neutral) white of the original?  Would that explain why the print (and soft proof) came out neutral, while soft proofing and printing with either RelCol or Perceptual were not as successful at neutralizing the blue?


Yes, that is how I understand the situation. If you are printing to a medium with a bluish coloration using absolute colorimetric, yellow would be added to neutralize the blue. If you used a rather broad border of the medium in its normal state around the image, the eye would accommodate to the "white" of the border and then the "white" in the image would appear yellow, since yellow had been added to the white in the original image. If you viewed the print with no border in a neutral surround, then the white in the print would appear neutral. It's a bit confusing. Perhaps the DigitalDog can comment.

Bill
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digitaldog
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« Reply #12 on: March 25, 2009, 01:03:04 PM »
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The absolute colorimetric rendering intent reproduces the exact color that existed in the source—absolutely.

If the source was light color on the dingy yellow-white of newsprint, the resulting color on your brilliant coated ink jet paper will be dingy yellow. This intent is really designed for making one device simulate the appearance of another device for use in proofing. Perhaps you wish to proof on an Epson printer what your image would look like on a printing press. The two papers (Epson and press) would have different paper whites. The paper used on press likely would have a slightly yellowier and darker appearance. The white of any
paper greatly affects our perception of all the other colors. The paper white of the Epson would now appear slightly darker and yellow to match the paper white of the press. That is the reason this rendering intent is utilized for proofing. Nevertheless, it is useful when you want to make one device mimic another!
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Andrew Rodney
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walter.sk
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« Reply #13 on: March 25, 2009, 01:18:44 PM »
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Quote from: digitaldog
The absolute colorimetric rendering intent reproduces the exact color that existed in the source—absolutely.

If the source was light color on the dingy yellow-white of newsprint, the resulting color on your brilliant coated ink jet paper will be dingy yellow. This intent is really designed for making one device simulate the appearance of another device for use in proofing. Perhaps you wish to proof on an Epson printer what your image would look like on a printing press. The two papers (Epson and press) would have different paper whites. The paper used on press likely would have a slightly yellowier and darker appearance. The white of any
paper greatly affects our perception of all the other colors. The paper white of the Epson would now appear slightly darker and yellow to match the paper white of the press. That is the reason this rendering intent is utilized for proofing. Nevertheless, it is useful when you want to make one device mimic another!

Over 10 years ago, with my first digital camera (a Nikon Coolpix 900) I naively asked the seemingly simple question, "How come the colors in my print don't match what I see on the monitor?"  Now, thousands upon thousands of dollars later, I am finally realizing how naive that question was and how slippery a slope I was entering.  I now have more knowledge than I ever wanted, a suspicion that there is a still bigger gap in what I yet need to learn, and a wistful resignation about the whole thing.  But when I see friends and colleagues first beginning to ask, with surprise, "How come my prints don't look like what I see on the monitor?" I guess I have to admit that the climb has been worth it.

I guess nobody said it would be easy.

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digitalshiver
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« Reply #14 on: March 31, 2009, 10:20:22 PM »
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walter, my man, here here!

nicely put. we can relate.

c
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Jonathan Wienke
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« Reply #15 on: April 06, 2009, 08:40:55 PM »
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Quote from: walter.sk
Over 10 years ago, with my first digital camera (a Nikon Coolpix 900) I naively asked the seemingly simple question, "How come the colors in my print don't match what I see on the monitor?"  Now, thousands upon thousands of dollars later, I am finally realizing how naive that question was and how slippery a slope I was entering.  I now have more knowledge than I ever wanted, a suspicion that there is a still bigger gap in what I yet need to learn, and a wistful resignation about the whole thing.  But when I see friends and colleagues first beginning to ask, with surprise, "How come my prints don't look like what I see on the monitor?" I guess I have to admit that the climb has been worth it.

I guess nobody said it would be easy.

How soon we forget the alchemy of selecting the proper color filter pack when printing optically from a color negative, and the variations introduced by using a different batch of film, chemicals, or paper during developing or printing--the good old days...weren't. The good news is that we are no longer at the mercy of the lab tech to get the colors in the print right. The bad news is that we need to learn some of the arcana of color management to improve upon the efforts of the lab rat.
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