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Author Topic: attention color whizes: non-typical sRGB/RGB/ProPhoto question  (Read 227693 times)

Peter_DL

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Re: attention color whizes: non-typical sRGB/RGB/ProPhoto question
« Reply #340 on: January 05, 2011, 07:32:52 pm »

The one new color space I would like to have in ACR/LR is ProPhoto RGB colors and a linear gamma as an output space. This would allow some Photoshop work done in a ProPhoto RGB linear gamma (I do have a working space profile for that) without having to do a gamma correction to linear and back. Alas, Thomas Knoll said that was pointless since doing the gamma conversion to/from/to isn't very destructive.

The one and only new internal processing space I would like to have in ACR/LR (aside from current linear gamma ProPhoto RGB) is a somewhat smaller internal working space. A kind of an earlier binding when the final target is a small output space. But that's off topic here, and once I find the time I'll open a new thread on this. Need to work out a good example on its usefulness. Referring to you as an author, I'd trust you know what I mean regarding the effort to publish something.
 
 
Do you have a shot with a portrait in a shadow of tree and a  asphalt road lit by Sun? That would be a good starting point. Or a shot taken with a fill flash in a room lit by incandescent lamps?

Comeon, if you have the right images for illustration please kindly just clip it in here.
 
 
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Iliah

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Re: attention color whizes: non-typical sRGB/RGB/ProPhoto question
« Reply #341 on: January 05, 2011, 07:51:26 pm »

> Comeon, if you have the right images for illustration please kindly just clip it in here.

I do not understand you. First, you have necessary images yourself - about 90% of images taken outside of a studio have some regions that show why current conversion technique is limiting. If that would not be the case no local editing to get natural colour shall be needed. Second, I can't "clip in" a raw image here.

Anyway. The moment I will see this discussion is getting back to something that is of interest to me I will continue. Those who feel that "classical" colour management is all they need - why worry? Just to put down those who bring in legitimate questions with maxims like "white balance changes color"? LOL.

Those who see how "classical" colour management (and it was not meant to address the problems of digital capture by the way) fails to satisfy their customers may want to take some of the points that were already discussed here.
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Peter_DL

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Re: attention color whizes: non-typical sRGB/RGB/ProPhoto question
« Reply #342 on: January 05, 2011, 08:57:02 pm »

The moment I will see this discussion is getting back to something that is of interest to me I will continue.

Oh, thanks.
 
 
Second, I can't "clip in" a raw image here.

... Those who feel that "classical" colour management is all they need - why worry? Just to put down those who bring in legitimate questions with maxims like "white balance changes color"? LOL.

Those who see how "classical" colour management (and it was not meant to address the problems of digital capture by the way) fails to satisfy their customers may want to take some of the points that were already discussed here.


The contradiction is that customers typically don't receive and view raw images. However, I'm not a professional in this business. So if you have a showcase for customer-dissatisfaction based on "classical" color management please just contribute. Ideally referring to the content of this thread. I'm all open for legitimate and illegitimate question (on color management).
Why am I under the impression that there is nothing more to come.

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Stephan Jones

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Re: attention color whizes: non-typical sRGB/RGB/ProPhoto question
« Reply #343 on: January 05, 2011, 09:11:05 pm »

Wow, I just read this whole thread and I want to thank Joofa for helping me understand a lot about the science of measurement. You are going to save me SO much time on my commute to work. You see, I've always been driving to work in kilometers. 15 kilometers to be exact. Now I realize that I can drive to work in miles and shave about 40% off my commute.

I'll attach a graph I made illustrating this fact.

The green line on the bottom is a number line (canonical and absolute). The blue line is my old commute 15 the red line is my new commute 9.32. You can tell by looking how much shorter my new commute will be (red line).

Remember, don't be unappreciative of the fact there is not a single coordinate system in this scenario. There are three in the same 2D space! One is the canonical number line whose "unit vector" length is fixed. (I can't take credit for this line of genius; I'm paraphrasing Joofa.)

Thanks Joofa! I'm going to save so much money. (Speaking of money, I'm asking my boss tomorrow if he'll switch my pay to Rupies. I just saw the conversion ratio!!)


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joofa

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Re: attention color whizes: non-typical sRGB/RGB/ProPhoto question
« Reply #344 on: January 05, 2011, 09:24:05 pm »

Wow, I just read this whole thread and I want to thank Joofa for helping me understand a lot about the science of measurement. You are going to save me SO much time on my commute to work. You see, I've always been driving to work in kilometers. 15 kilometers to be exact. Now I realize that I can drive to work in miles and shave about 40% off my commute.

I'll attach a graph I made illustrating this fact.

The green line on the bottom is a number line (canonical and absolute). The blue line is my old commute 15 the red line is my new commute 9.32. You can tell by looking how much shorter my new commute will be (red line).

Remember, don't be unappreciative of the fact there is not a single coordinate system in this scenario. There are three in the same 2D space! One is the canonical number line whose "unit vector" length is fixed. (I can't take credit for this line of genius; I'm paraphrasing Joofa.)

Thanks Joofa! I'm going to save so much money. (Speaking of money, I'm asking my boss tomorrow if he'll switch my pay to Rupies. I just saw the conversion ratio!!)




Stephen, unfortunately, what I have said is true. "Unit stimulus/vector" is a varying quantity for each primary. Your miles/km analogy is incorrect. Because that refers to the same entity being measured. I'm not talking about that at all. Please reread what I have written.

Joofa
« Last Edit: January 05, 2011, 11:05:40 pm by joofa »
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Graystar

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Re: attention color whizes: non-typical sRGB/RGB/ProPhoto question
« Reply #345 on: January 05, 2011, 10:18:06 pm »

Stephen, unfortunately, what I have said is true.

No, you’re wrong.  You have a fundamental misunderstand at the most basic level...your unwillingness to understand the reason for adaptation in color conversion.  You can’t seem to grasp neither the fact that color exist only in our minds, nor the implications of that fundamental truth.

At this point I think you're beyond help.  You're not going to change your thinking until you actually see your attempts at color conversion fail.  Only then will you question your incorrect assumptions.  Let's hope this happens sooner rather than later.  Hopefully, you won't spread your incorrect information too far. 
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joofa

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Re: attention color whizes: non-typical sRGB/RGB/ProPhoto question
« Reply #346 on: January 05, 2011, 10:35:03 pm »

I note that the mistake Stephen Jones is making has resulted in widely held misconceptions about colorimetry, including:

(1) a linear color space is not perceptual enough; resulting in Lab space being overrated
(2) color space distance metrics derived from nonlinear coordinate systems are necessarily better
(3) unrealistic angular dependencies of various color stimuli

Joofa
« Last Edit: January 05, 2011, 10:43:22 pm by joofa »
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joofa

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Re: attention color whizes: non-typical sRGB/RGB/ProPhoto question
« Reply #347 on: January 05, 2011, 10:57:23 pm »

No, you’re wrong.  You have a fundamental misunderstand at the most basic level...

Anybody could be wrong and I am no exception. I am trying to learn.

Quote
You can’t seem to grasp neither the fact that color exist only in our minds, nor the implications of that fundamental truth.

That was the colorimetry of 80 years ago. Now it is being put on a rigorous linear algebraic framework in an overall signal processing environment.

Quote
At this point I think you're beyond help.  You're not going to change your thinking until you actually see your attempts at color conversion fail.  Only then will you question your incorrect assumptions.  Let's hope this happens sooner rather than later.  Hopefully, you won't spread your incorrect information too far.

Gosh, you have an axe to grind against me.

Joofa
« Last Edit: January 05, 2011, 10:59:39 pm by joofa »
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Re: attention color whizes: non-typical sRGB/RGB/ProPhoto question
« Reply #348 on: January 05, 2011, 11:11:36 pm »

Anybody could be wrong and I am no exception. I am trying to learn.

It feels more like you're trying to dictate.  You show no willingness whatsoever to explore the possibility that you may be wrong.

That was the colorimetry of 80 years ago. Now it is being put on a rigorous linear algebraic framework in an overall signal processing environment.

Statements like this just prove my point.
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Stephan Jones

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Re: attention color whizes: non-typical sRGB/RGB/ProPhoto question
« Reply #349 on: January 06, 2011, 12:10:24 am »

Stephen, unfortunately, what I have said is true. "Unit stimulus/vector" is a varying quantity for each primary. Your miles/km analogy is incorrect. Because that refers to the same entity being measured. I'm not talking about that at all. Please reread what I have written.

Nope, not at all.  Consider this. I take my drive to work in kilometers and measure it in numbers, call it A, and then I  I take my drive to work in miles and measure in numbers, and call it B. And A is not the same as B! A is greater that B! These two different sets of numbers are related by a conversion model say, KM to Miles, but that is all it is about. Now suppose I decide to measure A and B in a system which has rational numbers. I have selected my distances (number line coordinates.) However, there is still a very important step here that Joofa is not realizing. While I have picked my numbers I have not defined that while measuring A and B which what is my units. I have two natural choices, either pick KM or miles, or  I can even pick a third unrelated unit. But we shall only concentrate on the first two. KM is set to produce a distance value of 15 for A, but something else for B. What Joofa seems unappreciative of the fact is that when he throws in conversion model it internally restructures the metric system, so that miles are now set to produce the number 9.32 for B, effectively becoming 15. At this stage he forgets about distance A, which still exists. And if we measure A in the new system then it will be a longer drive.
« Last Edit: January 06, 2011, 12:12:14 am by Stephan Jones »
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joofa

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Re: attention color whizes: non-typical sRGB/RGB/ProPhoto question
« Reply #350 on: January 06, 2011, 12:18:29 am »

Nope, not at all.  Consider this. I take my drive to work in kilometers and measure it in numbers, call it A, and then I  I take my drive to work in miles and measure in numbers, and call it B. And A is not the same as B! A is greater that B! These two different sets of numbers are related by a conversion model say, KM to Miles, but that is all it is about. Now suppose I decide to measure A and B in a system which has rational numbers. I have selected my distances (number line coordinates.) However, there is still a very important step here that Joofa is not realizing. While I have picked my numbers I have not defined that while measuring A and B which what is my units. I have two natural choices, either pick KM or miles, or  I can even pick a third unrelated unit. But we shall only concentrate on the first two. KM is set to produce a distance value of 15 for A, but something else for B. What Joofa seems unappreciative of the fact is that when he throws in conversion model it internally restructures the metric system, so that miles are now set to produce the number 9.32 for B, effectively becoming 15. At this stage he forgets about distance A, which still exists. And if we measure A in the new system then it will be a longer drive.

Interesting parody ;D

May be if you pay close attention to what I wrote you can figure out where are you going wrong?

Sincerely,

Joofa
« Last Edit: January 09, 2011, 07:59:33 am by joofa »
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jbrembat

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Re: attention color whizes: non-typical sRGB/RGB/ProPhoto question
« Reply #351 on: January 06, 2011, 04:00:37 am »

Quote
Anybody could be wrong and I am no exception. I am trying to learn.
You are not trying to learn.
You are trying to assert that Adobe 1998 blue color is outside of ProPhoto gamut.
You are wrong and you are not able to understand your mistake.

You are not trying to learn.

Jacopo
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ejmartin

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Re: attention color whizes: non-typical sRGB/RGB/ProPhoto question
« Reply #352 on: January 06, 2011, 07:54:40 am »

Nope, not at all.  Consider this. I take my drive to work in kilometers and measure it in numbers, call it A, and then I  I take my drive to work in miles and measure in numbers, and call it B. And A is not the same as B! A is greater that B! These two different sets of numbers are related by a conversion model say, KM to Miles, but that is all it is about. Now suppose I decide to measure A and B in a system which has rational numbers. I have selected my distances (number line coordinates.) However, there is still a very important step here that Joofa is not realizing. While I have picked my numbers I have not defined that while measuring A and B which what is my units. I have two natural choices, either pick KM or miles, or  I can even pick a third unrelated unit. But we shall only concentrate on the first two. KM is set to produce a distance value of 15 for A, but something else for B. What Joofa seems unappreciative of the fact is that when he throws in conversion model it internally restructures the metric system, so that miles are now set to produce the number 9.32 for B, effectively becoming 15. At this stage he forgets about distance A, which still exists. And if we measure A in the new system then it will be a longer drive.

To run with this analogy a bit more, I think the situation is a bit more accurately translated as the funhouse illusion known as an Ames Room:



Your height stays fixed but depending on the environment you appear to be taller or shorter.  Similarly in the present discussion, the physical quantity -- the XYZ spectral responses -- stay fixed; what changes is your perception of the color depending on the environment in which those spectral responses are perceived.  The man on the right appears to be out of gamut ;)

In the other direction, a quite direct analog of the Ames Room was given many pages ago here, where someone posted an image with a checkerboard in it, depending on whether it was in light or shadow, a square with the same tristimuli appeared to be lighter or darker depending on its surrounding squares.
« Last Edit: January 06, 2011, 10:05:57 am by ejmartin »
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emil

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Re: attention color whizes: non-typical sRGB/RGB/ProPhoto question
« Reply #353 on: January 06, 2011, 08:37:35 am »

Similarly in the present discussion, the physical quantity -- the XYZ spectral responses -- stay fixed; what changes is your perception of the color depending on the environment in which those spectral responses are perceived.

Right...those environments being the Standard Illuminants. Each standard illuminant has a calculated white point in the XYZ space. The human perception of an XYZ color depends on which white point you're "looking" from.

If you convert an RGB space into XYZ using the white point of the RGB space, that white point now defines where the human is "looking" from.  When converting that same human "point of view" into a another RGB space, you can't simply change the XYZ white point...that changes where you're "looking" from.

But that is exactly what Joofa is doing with his "absolute" conversions.  There's nothing absolute about them...you're simply using the white point of the destination RGB space to reset the white point of the XYZ space...you’re now “looking” at the XYZ coordinates from a different place, and that makes the color appear different.

A same-color conversion that changes the color, is no conversion at all.  Who cares if a different blue isn’t in the Pro Photo space?

(Watch...Joofa will respond with, “No, look at the chart.”)


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Peter_DL

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Re: attention color whizes: non-typical sRGB/RGB/ProPhoto question
« Reply #354 on: January 06, 2011, 08:57:17 am »

What about multispectral imaging in a very narrow bandwidth around those non-overlapping gamuts?

Let’s assume we stand outside the house at somewhat D50 light. Through the windows we see there is colder D65 light inside the house. Let’s further assume that the camera does not impose any limitations to capture the gamut of such scene.

Then comes the conversion of the demosaiced "Raw" RGB data to the working space or internal working space of the Raw converter. Here we have the option to control white-point-mapping by means of the given Temp. and Tint sliders. Now there are two different cases whether we click-whitebalance on a D50 white or a D65 white from the initial scene. And we further can construe different cases depending on the working spaces that are tried here. Let’s stay with regular Adobe RGB D65 vs. ProPhoto RGB D50, or linear-gamma versions thereof when we talk about the internal working space of the Raw converter.

Your assumption - if I understand it correctly – is that Adobe RGB could hold specific colors from inside the house which are out-of-gamut with ProPhoto RGB. And you may be right in an absolute colorimetric sense: White to saturated blue colors from inside the house can be out-of-ProPhoto RGB when we click-whitebalance on the D50 reference white of the scene. Same colors can be inside Adobe RGB when we click-whitebalance on the D65 white from inside the house.
But then we could as well have click-whitebalanced on the D65 white while using the ProPhoto RGB space, thus capturing all in-house colors and probably much more from outside the house.

The point here is that it does not seem to be possible to freeze the absolute colorimetric differences between Adobe RGB and ProPhoto RGB. It is becoming irrelevant.
The same click-whitebalance operation changes its meaning from somehow AbsCol (e.g. scene D65 white to Adobe RGB D65) to somehow RelCol (scene D65 white to ProPhoto D50) depending on the working space used. Subsequent conversion to the monitor white is RelCol anyway.

Peter

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« Last Edit: January 06, 2011, 09:01:59 am by DPL »
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joofa

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Re: attention color whizes: non-typical sRGB/RGB/ProPhoto question
« Reply #355 on: January 06, 2011, 09:29:02 am »

Your assumption - if I understand it correctly – is that Adobe RGB could hold specific colors from inside the house which are out-of-gamut with ProPhoto RGB.

Hi Peter,

I mentioned multispectral imaging in a narrow bandwidth.

I did not say colors coming from a house - typically they are wideband and even a few narrowband colors are drowned in a sea of otherwise those colors that have respresentation in both Adobe RGB (D65) and Adobe RGB (D50). So that the traditionally held conventional photography viewpoint to "keep neutrals the same" suffices (by chromatic transformation), for usual photographs, because, who cares if a few colors are off, and even if somebody cares, then as Iliah Borg says, manual intervention is employed to develop them to liking.

Sincerely,

Joofa
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joofa

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Re: attention color whizes: non-typical sRGB/RGB/ProPhoto question
« Reply #356 on: January 06, 2011, 09:31:12 am »

Similarly in the present discussion, the physical quantity -- the XYZ spectral responses -- stay fixed; what changes is your perception of the color depending on the environment in which those spectral responses are perceived.  

I think with those cool graphs Jc1 has independently verified that the same XYZ color becomes in-gamut for Adobe RGB (D65) and out-of-gamut for Adobe RGB (D50), and hence, by extension to Prophoto RGB (D50).

Sincerely,

Joofa
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joofa

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Re: attention color whizes: non-typical sRGB/RGB/ProPhoto question
« Reply #357 on: January 06, 2011, 09:36:00 am »

(Watch...Joofa will respond with, “No, look at the chart.”)

No, I won't ask you to look at any of my charts. Have you ever looked at the standard chromacity diagram presented in countless books and available everywhere online? What do you think is wrong with it?

Joofa
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joofa

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Re: attention color whizes: non-typical sRGB/RGB/ProPhoto question
« Reply #358 on: January 06, 2011, 09:40:03 am »


But then we could as well have click-whitebalanced on the D65 white while using the ProPhoto RGB space, thus capturing all in-house colors and probably much more from outside the house.


Isn't that the same as when I said to use Prophoto RGB (D65) instead of standardized Prophoto RGB (D50), but you took objection to that?

Sincerely,

Joofa
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Re: attention color whizes: non-typical sRGB/RGB/ProPhoto question
« Reply #359 on: January 06, 2011, 10:04:51 am »

Have you ever looked at the standard chromacity diagram presented in countless books and available everywhere online? What do you think is wrong with it?

Being a human invention, there's nothing wrong with it.  It is exactly what its creators intended it to be.
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