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Author Topic: attention color whizes: non-typical sRGB/RGB/ProPhoto question  (Read 222131 times)

digitaldog

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Re: attention color whizes: non-typical sRGB/RGB/ProPhoto question
« Reply #600 on: January 08, 2011, 09:49:14 pm »

This is a good read from scienceblogs that demonstrates a proper response to unlabeled graphs:

In the same vein:
http://www.scottberkun.com/essays/53-how-to-detect-bullshit/
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joofa

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Re: attention color whizes: non-typical sRGB/RGB/ProPhoto question
« Reply #601 on: January 08, 2011, 09:53:41 pm »

I think you are joking!  ;D  This software is very good.  The Absolute displays are very accurate because it was created by experts.  I think you would like Gamutvision.  Their expertise has helped us all to agree that Adobe RGB is fully contained within Pro Photo, as shown in the display I posted earlier.

http://www.luminous-landscape.com/forum/index.php?topic=49940.msg414096#msg414096

Too bad I don't have any friends who could attest to my expertise. :-\ A long time ago I tried to endear myself to Emil Martinec, but he hates me. A couple more have been added on this thread  >:(

Joofa
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Eric Myrvaagnes

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Re: attention color whizes: non-typical sRGB/RGB/ProPhoto question
« Reply #602 on: January 08, 2011, 11:54:12 pm »

Too bad I don't have any friends who could attest to my expertise. :-\ A long time ago I tried to endear myself to Emil Martinec, but he hates me. A couple more have been added on this thread  >:(

Joofa
I would have to say that it's largely because
1.   You have refused over and over again to answer simple direct questions from others who have tried very hard to understand what you are trying to say, and
2.   You have repeatedly insulted a great number of serious and highly knowledgeable experts who have very patiently tried to engage you in rational discourse, and
3.   You have steadfastly refused to explain how you arrive at the claims you seem to be making.

I find it hard to understand how you obtained a Ph.D. in engineering (according to Google) when you don't seem to understand the necessity of labeling the axis and units on a graph. For that error alone you would have failed any of the hundreds of college freshman-level math courses I have taught.

Eric
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Iliah

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Re: attention color whizes: non-typical sRGB/RGB/ProPhoto question
« Reply #603 on: January 09, 2011, 12:34:58 am »

> I would have to say that it's largely because
> 1.   You have refused over and over again to answer simple direct questions

I'm afraid he did answer, but the answers were not understood. Same as the answer Bruce gave in his e-mail that was quoted here.

> you don't seem to understand the necessity of labeling the axis and units on a graph. For that error alone you would have failed any of the hundreds of college freshman-level math courses I have taught.

Everything brought to the extreme turns into rubbish. In this case the labels and scales for the axis were pretty clear from the context (if only one knows it), and if they were not - the (polite) question of what are they should be asked immediately. Now this looks like a straw. Labeling axis does not help if the opponent is on an agenda or does not know the subject.

Here is a small story about labeling axis. Tamm (http://en.wikipedia.org/wiki/Igor_Tamm ) once was stopped by a post-graduate in a corridor of FIAN ( http://en.wikipedia.org/wiki/Lebedev_Physical_Institute ). The guy was asking for an explanation of a graph he made from an experiment. Tamm explained. After he finished they recognized the graph was upside down. They rotated the paper and Tamm gave another explanation.
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joofa

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Re: attention color whizes: non-typical sRGB/RGB/ProPhoto question
« Reply #604 on: January 09, 2011, 12:42:45 am »

I find it hard to understand how you obtained a Ph.D. in engineering (according to Google)

Oh, they are dime a dozen these days. Don't worry about it. I can probably try to arrange one for you if you like. Very handy for a false sense of ego. And people take you more seriously.

Quote
you would have failed any of the hundreds of college freshman-level math courses I have taught.

Glad I never attended your college. I wasn't good in math anyway.

Regards,

Joofa
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Iliah

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Re: attention color whizes: non-typical sRGB/RGB/ProPhoto question
« Reply #605 on: January 09, 2011, 12:43:15 am »

> I think you are joking!

Think again because he does not. There is an error either in how you use it or in the particular calculation module implementation. Simple basic math as well as graphs made by those who understand how to apply AbsCol; and the email from Bruce all give the correct answer.

> The Absolute displays are very accurate because it was created by experts.

Even experts make mistakes, especially in chromatic adaptation. I also suggest that you present the sequence of operations you used so that your steps can be independently verified; and if the error is in the software a proper report given to Norman and his team.
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sandymc

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Re: attention color whizes: non-typical sRGB/RGB/ProPhoto question
« Reply #606 on: January 09, 2011, 02:18:02 am »

> if you were using twists to achieve non-linear sensor space to RGB conversion

Why would that be helpful?

To address the issues discussed in post 560. In theory :)

As mentioned in a previous post, personally I've never seen a practical example of where hue twists were helpful in getting from camera space to a reference space. But that doesn't mean there isn't a way to do so. Hue twists are however, imho, very useful in achieving a particular "look".

Sandy
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Graystar

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Re: attention color whizes: non-typical sRGB/RGB/ProPhoto question
« Reply #607 on: January 09, 2011, 05:54:23 am »

> I think you are joking!

Think again because he does not. There is an error either in how you use it or in the particular calculation module implementation. Simple basic math as well as graphs made by those who understand how to apply AbsCol; and the email from Bruce all give the correct answer.

> The Absolute displays are very accurate because it was created by experts.

Even experts make mistakes, especially in chromatic adaptation. I also suggest that you present the sequence of operations you used so that your steps can be independently verified; and if the error is in the software a proper report given to Norman and his team.

No.  There is no mistake.  Bruce Lindbloomís email agrees with my display.  Please look again.  The display is correct.  I can't overemphasize that fact.
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Peter_DL

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Re: attention color whizes: non-typical sRGB/RGB/ProPhoto question
« Reply #608 on: January 09, 2011, 08:57:49 am »

 
Interesting article by (Prof.) Gernot Hoffmann,
page 4 also expands on "chromatic adaptation is not perfect":

http://www.fho-emden.de/~hoffmann/cmsicc08102003.pdf

Peter

--

« Last Edit: January 09, 2011, 08:59:56 am by Peter_DL »
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Graystar

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Re: attention color whizes: non-typical sRGB/RGB/ProPhoto question
« Reply #609 on: January 09, 2011, 09:45:26 am »

Too bad I don't have any friends who could attest to my expertise. :-\ A long time ago I tried to endear myself to Emil Martinec, but he hates me. A couple more have been added on this thread  >:(

Thatís okay Joofa...anyone can be mistaken. We are all here to learn.  Here is a plot of Adobe RGB against Pro Photo from Bruce Lindbloom 3D Gamut Viewer.  His 3D view also has Adobe RGB contained in Pro Photo...like the Gamutvision display.  These are the correct views.  I can't overemphasize that fact.

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joofa

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Re: attention color whizes: non-typical sRGB/RGB/ProPhoto question
« Reply #610 on: January 09, 2011, 10:08:54 am »

Thatís okay Joofa...anyone can be mistaken. We are all here to learn.  Here is a plot of Adobe RGB against Pro Photo from Bruce Lindbloom 3D Gamut Viewer.  His 3D view also has Adobe RGB contained in Pro Photo...like the Gamutvision display.  These are the correct views.  


Hi Graystar,

They are Adobe RGB (D50) and not Adobe RGB (D65). i have mentioned this several times.

Quote
I can't overemphasize that fact.

Haha, you parodying me.  ;D

Sincerely,

Joofa
« Last Edit: January 09, 2011, 10:10:47 am by joofa »
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tho_mas

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Re: attention color whizes: non-typical sRGB/RGB/ProPhoto question
« Reply #611 on: January 09, 2011, 10:10:55 am »

Quote
... when all PropPhoto blues are clipping converting relcol or abscol to AdobeRGB as target this consequently means that there is no AdobeRGB blue that is outside of ProPhoto.
The inverse test works reasonably well with the Granger Rainbow posted many pages ago,
ProPhoto RGB blues do not clip when converting AbsCol to Adobe RGB
(within the limits that we can believe in oog marks).
in how far inverse? I was talking about soure: ProPhotoRGB | target: AdobeRGB... ?
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tho_mas

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Re: attention color whizes: non-typical sRGB/RGB/ProPhoto question
« Reply #612 on: January 09, 2011, 10:12:19 am »

Here is a plot of Adobe RGB against Pro Photo from Bruce Lindbloom 3D Gamut Viewer.  His 3D view also has Adobe RGB contained in Pro Photo...like the Gamutvision display.
this is relcol
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joofa

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Re: attention color whizes: non-typical sRGB/RGB/ProPhoto question
« Reply #613 on: January 09, 2011, 10:16:43 am »

Hi Peter,

Thanks for the pdf link. Interesting information.

Sincerely,

Joofa
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ejmartin

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Re: attention color whizes: non-typical sRGB/RGB/ProPhoto question
« Reply #614 on: January 09, 2011, 10:17:48 am »

A long time ago I tried to endear myself to Emil Martinec, but he hates me.

Joofa

A bit too strong; there are very few people I loathe, and you are not one of them.  Let's just say there have been times I got annoyed at your tendency to focus on irrelevant technicalities.  
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tho_mas

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Re: attention color whizes: non-typical sRGB/RGB/ProPhoto question
« Reply #616 on: January 09, 2011, 10:35:58 am »

No.  The Gamutvision display is Absolute.
Bruce Lindblooms grapher that you've just posted is relcol (and of course correct for relcol).
Apparently you seem to think that it displays the same as Gamutvisions grapher:
Here is a plot of Adobe RGB against Pro Photo from Bruce Lindbloom 3D Gamut Viewer.  His 3D view also has Adobe RGB contained in Pro Photo...like the Gamutvision display.  These are the correct views.
IMHO the Gamutvision grapher doesn't make sense at all.
Where do you suspect AdobeRGB's white in this graph?: http://www.luminous-landscape.com/forum/index.php?topic=49940.msg414096#msg414096


« Last Edit: January 09, 2011, 10:45:39 am by tho_mas »
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tgray

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Re: attention color whizes: non-typical sRGB/RGB/ProPhoto question
« Reply #617 on: January 09, 2011, 11:37:45 am »

your tendency to focus on irrelevant technicalities.  

I think that sums it up for me.  It does seem to me that joofa has a point, but it's most likely not relevant for everyday use.  Maybe it is, but most probably not.  However there seem to be those who won't acknowledge that he might have a point.  Once you do, you can then move onto the next stage - Is it relevant?

Though 'made by experts', 'nobody does it that way', etc. are not valid arguments for correctness or relevance. 
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bjanes

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Re: attention color whizes: non-typical sRGB/RGB/ProPhoto question
« Reply #618 on: January 09, 2011, 11:58:12 am »

Thatís okay Joofa...anyone can be mistaken. We are all here to learn.  Here is a plot of Adobe RGB against Pro Photo from Bruce Lindbloom 3D Gamut Viewer.  His 3D view also has Adobe RGB contained in Pro Photo...like the Gamutvision display.  These are the correct views.  I can't overemphasize that fact.



Here are plots of Adobe RGB and ProPhoto RGB in Colorthink Pro using Relative Colorimetric and Absolute Colorimetric. The program seems a bit flakey and does not always show the same results, but with Absolute Colorimetric working properly the white points should be different. I set both displays to opaque. The ProPhoto RGB is in color and the Adobe RGB is white so they can't be mixed up. With Relative Colorimetric, the white point is adjusted and Adobe RGB is completely contained in ProPhoto RGB.

With Absolute Colorimetric, the white points are different and a portion of Adobe RGB is outside the gamut of ProPhoto RGB as Joofa has maintained.

Regards,

Bill


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Iliah

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Re: attention color whizes: non-typical sRGB/RGB/ProPhoto question
« Reply #619 on: January 09, 2011, 12:13:53 pm »

> It does seem to me that joofa has a point, but it's most likely not relevant for everyday use.

If you look at how proofing is done absolute colorimetric intent is in use there for certain cases. The goal of proofing is to mimic behavior of one media using a different media. Consider the real life scene to be presented to the eye observing it in person as one media, and the presentation of that scene on a display or on a print as the other media. Now what are we going to use as the rendering intent if we want to recreate the original impression of the scene?
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