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Author Topic: attention color whizes: non-typical sRGB/RGB/ProPhoto question  (Read 228221 times)

joofa

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Re: attention color whizes: non-typical sRGB/RGB/ProPhoto question
« Reply #200 on: January 04, 2011, 06:40:06 pm »

Joofa, can your point be summarized like this?

The XYZ values of Adobe1998 blue primary [0.1881852, 0.0752741, 0.9911085] when viewed in a D50 environment are out of gamut in ProPhotoRGB?


Mark, you get the trophy. What took you so long to realize that? ??? ??? ??? ??? ???

Joofa
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MarkM

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Re: attention color whizes: non-typical sRGB/RGB/ProPhoto question
« Reply #201 on: January 04, 2011, 06:42:19 pm »

Mark, you get the trophy. What took you so long to realize that? ??? ??? ??? ??? ???

Joofa

Great! We agree! We can stop now.

There is one little problem, however:

The XYZ values of Adobe1998 blue primary [0.1881852, 0.0752741, 0.9911085] when viewed in a D50 environment are also out of gamut of Adobe1998 RGB.
« Last Edit: January 04, 2011, 06:44:49 pm by MarkM »
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Schewe

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Re: attention color whizes: non-typical sRGB/RGB/ProPhoto question
« Reply #202 on: January 04, 2011, 06:43:40 pm »

Did you miss that part about:

"If one agrees that R=G=B is neutral for both profiles, regardless of the reference whites, then chromatic adaptation must be used to bring them both to the same reference. In that context, AdobeRGB blue lies inside the gamut of ProPhotoRGB."

Pardon me but I don't know how you can get from Adobe RGB D65 to ProPhoto RGB in real life (as apposed to calculations only) without doing a "chromatic adaptation". Isn't that what color transforms are all about? Pretty sure that's how Photoshop handles a color space transform...(and Camera Raw and Lightroom).

We are talking about the real world, right? Photographic images? Not arbitrary color references we can't see and photograph?
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joofa

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Re: attention color whizes: non-typical sRGB/RGB/ProPhoto question
« Reply #203 on: January 04, 2011, 06:46:24 pm »

Great! We agree! We can stop now.

There is one little problem, however:

The XYZ values of Adobe1998 blue primary [0.1881852, 0.0752741, 0.9911085] when viewed in a D50 environment are also out of gamut of Adobe1998 RGB.

Yes, and I have said that tons of time before! The last time I said that was just before this message and I repeat it here:

Quote
Joofa said:

The reason Adobe RGB (50) can be contained is that because it has been chormatic-adaptation-transformed from Adobe RGB (D65), and this process has already stripped that offending blue Adobe RGB (D65) primary. After Bradford transformation Adobe RGB (D50) gets a new blue primary.

Sincerely,

Joofa
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MarkM

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Re: attention color whizes: non-typical sRGB/RGB/ProPhoto question
« Reply #204 on: January 04, 2011, 06:49:57 pm »

Yes, and I have said that tons of time before! The last time I said that was just before this message and I repeat it here:

Great! We still agree!

The XYZ values of Adobe1998 blue primary [0.1881852, 0.0752741, 0.9911085] when viewed in a D50 environment is out of gamut in both ProPhotoRGB and Adobe1998RGB.

So remind me again, why this color, which is out of both gamuts, is relevant to a comparison between the two?
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Iliah

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Re: attention color whizes: non-typical sRGB/RGB/ProPhoto question
« Reply #205 on: January 04, 2011, 06:53:26 pm »

As I see it, the problem is with understanding that we can't (and do not want to) run full adaptation.
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Farmer

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Re: attention color whizes: non-typical sRGB/RGB/ProPhoto question
« Reply #206 on: January 04, 2011, 06:56:53 pm »

Farmer, I don't think you are being fair here. If I had listed only case (1) in my note and insisted that is the only option then it would have been something. I clearly provided 4 different cases so that people can understand what is going on here.

I'm not being unfair at all.  You could have provided 42 different cases, but if only one of them applies to the practical application then the other 41 are mildly interesting in an academic way, but useless for any other.  If the academic discussion leads to a new practical application, then that's wonderful.  Such things do happen.  However, unless you can show or at least give some idea of how your premise can or might be useful in a practical way, then unfortunately it remains less than useful.

So if there's somewhere you can lead with this to suggest how it might be useful (changing the way CMMs work or some new technology that will significantly change the capture space of cameras, or a new printing or display method - etc etc) then please go ahead and I guarantee that all and sundry here will be listening and eager to understand and learn.

I don't think this has been a waste of bandwidth and the discussion has likely been useful (it has to me - I'm not a colour scientist but I try to read and understand as much as possible - it has a lot of benefit for my job).  It's time to either move to the next stage - practical application - or move on to the next topic and leave this one for reference.

It's not really a big deal.  I got called out recently a thread.  I had no intention of being an arse, but it was perceived that way by some.  You move on and try to avoid it.  I don't think you've been an arse here, but it gets pretty close when you start commenting on people's post count numbers or suggesting that people should becomes more learned in an area without presenting your own credentials.  I understand that sometimes it's not appropriate to background yourself, but in those cases you have to learn to suffer for the benefit of some level of anonymity.  Such is life :-)
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Phil Brown

joofa

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Re: attention color whizes: non-typical sRGB/RGB/ProPhoto question
« Reply #207 on: January 04, 2011, 07:02:24 pm »

Great! We still agree!
So remind me again, why this color, which is out of both gamuts, is relevant to a comparison between the two?

Mark, I thought you were beginning to understand this process, but it seems you are derailing again. ;D The intent was to show that in linear transformations akin to absolute colorimetry, Adobe RGB (D65) contains saturated blue colors that have no representation in Adobe RGB (D50) or Prophoto RGB (D50).

Hope that helps.

Regards,

Joofa
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MarkM

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Re: attention color whizes: non-typical sRGB/RGB/ProPhoto question
« Reply #208 on: January 04, 2011, 07:05:10 pm »

Adobe RGB (D65) contains saturated blue colors…

I thought we just agreed that this color is out of gamut in Adobe1998 RGB.
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joofa

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Re: attention color whizes: non-typical sRGB/RGB/ProPhoto question
« Reply #209 on: January 04, 2011, 07:06:33 pm »

I'm not being unfair at all.  You could have provided 42 different cases, but if only one of them applies to the practical application then the other 41 are mildly interesting in an academic way, but useless for any other.  

Iliah Borg just gave an example when that is relevant. Please see that above.

Quote
If the academic discussion leads to a new practical application, then that's wonderful.  Such things do happen.  However, unless you can show or at least give some idea of how your premise can or might be useful in a practical way, then unfortunately it remains less than useful.

See above.

Quote
It's not really a big deal.  I got called out recently a thread.  I had no intention of being an arse, but it was perceived that way by some.  You move on and try to avoid it.  I don't think you've been an arse here, but it gets pretty close when you start commenting on people's post count numbers or suggesting that people should becomes more learned in an area without presenting your own credentials.  I understand that sometimes it's not appropriate to background yourself, but in those cases you have to learn to suffer for the benefit of some level of anonymity.  Such is life :-)

I fully realize that I was a little politically incorrect a few times, and for that I apologize to everybody including digital dog. But the personal attacks were not started by me. However, I still offer my apology, especially to digital dog.

On the credentials front I thought my arguments would speak for me. But apparently not. You can google me if you want to find my background  ;D

Best regards,

Joofa
« Last Edit: January 04, 2011, 07:11:36 pm by joofa »
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Joofa
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joofa

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Re: attention color whizes: non-typical sRGB/RGB/ProPhoto question
« Reply #210 on: January 04, 2011, 07:08:43 pm »

I thought we just agreed that this color is out of gamut in Adobe1998 RGB.

Mark what happened to you? Not in Adobe RGB (D65). We are talking about saturated blues around Adobe RGB (D65).

Joofa
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Graystar

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Re: attention color whizes: non-typical sRGB/RGB/ProPhoto question
« Reply #211 on: January 04, 2011, 07:13:10 pm »

As I see it, the problem is with understanding that we can't (and do not want to) run full adaptation.
Adaptation is a necessary function of color space conversion.  What is your justification for not using it?

Let’s say someone wants to convert Celsius to Fahrenheit.  So you tell the person, “There are 1.8 degrees F to every degree C, so multiply your C by 1.8.”  Then you say, “But wait...the Fahrenheit freezing point is not zero, so you have to add 32 to your result to match the freezing points.”  At this point the person says, “But I don’t want to add 32 to my result.”

That is exactly what you’re saying when you say you don’t want to execute adaptation.  You’re performing half the required conversion, and then making declarations about the results that are only partially processed.  It’s like saying 10 C equals 18 F...true if you’re talking about a change in temperature, false if you’re talking about the current weather.
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Iliah

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Re: attention color whizes: non-typical sRGB/RGB/ProPhoto question
« Reply #212 on: January 04, 2011, 07:15:40 pm »

> He made the same exact mistake.  He even admits it...

LOL See, you think of one or another colour space. Now we are talking about both co-existing in the same scene. Ever wondered why shadows look blue while the whole scene is lit by sun?
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MarkM

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Re: attention color whizes: non-typical sRGB/RGB/ProPhoto question
« Reply #213 on: January 04, 2011, 07:15:44 pm »

I'll start again:

The XYZ values of Adobe1998 blue primary [0.1881852, 0.0752741, 0.9911085] when viewed in a D50 environment is out the ProPhotoRGB gamut.
Agreed

The XYZ values of Adobe1998 blue primary [0.1881852, 0.0752741, 0.9911085] when viewed in a D50 environment areisalso out of the Adobe1998RGB (D65) gamut.
Agreed

This color, represented by XYZ [0.1881852, 0.0752741, 0.9911085] viewed in a D50 environment is out of the gamut of both profiles in question. So again, why do we care about it?
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Farmer

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Re: attention color whizes: non-typical sRGB/RGB/ProPhoto question
« Reply #214 on: January 04, 2011, 07:17:55 pm »

Iliah Borg just gave an example when that is relevant. Please see that above.

Esoteric.  Hardly in the realm of practical application without further expansion.  You're bringing this to the table - detail the practical application.

On the credentials front I thought my arguments would speak for me. But apparently not. You can google me if you want to find my background  ;D

I've been using the internet since 1991, but thanks for the lesson...
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Phil Brown

joofa

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Re: attention color whizes: non-typical sRGB/RGB/ProPhoto question
« Reply #215 on: January 04, 2011, 07:20:46 pm »

This color, represented by XYZ [0.1881852, 0.0752741, 0.9911085] viewed in a D50 environment is out of the gamut of both profiles in question. So again, why do we care about it?

Because it is not outside Adobe RGB (D65)'s gamut and can be represented in it fine.

Joofa
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Iliah

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Re: attention color whizes: non-typical sRGB/RGB/ProPhoto question
« Reply #216 on: January 04, 2011, 07:21:06 pm »

> ProPhoto RGB is STILL the ONLY color space I know of that can contain ALL the colors a camera can capture and ALL the colors modern inkjets can print.

Operative word is "know". Cameras do not have gamuts while ProPhoto RGB does have a gamut, and not the widest possible.
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MarkM

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Re: attention color whizes: non-typical sRGB/RGB/ProPhoto question
« Reply #217 on: January 04, 2011, 07:29:04 pm »

Quote from: MarkM
There is one little problem, however:
The XYZ values of Adobe1998 blue primary [0.1881852, 0.0752741, 0.9911085] when viewed in a D50 environment are also out of gamut of Adobe1998 RGB.

Quote from: Joofa
Yes, and I have said that tons of time before!

Because it is not outside Adobe RGB (D65)'s gamut and can be represented in it fine.

Perhaps in view of the above, you can understand why I'm confused.

But regardless… The color XYZ [0.1881852, 0.0752741, 0.9911085] viewed in a D50 environment is not the same color as XYZ [0.1881852, 0.0752741, 0.9911085] viewed in a D65 environment. They don't match—you can show this experimentally. Having the same XYZ numbers is not enough to tell if they are the same color—color is what is perceived.

The color AdobeRGB1998[0, 0, 255] does not equal XYZ [0.1881852, 0.0752741, 0.9911085] viewed in a D50 environment.
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tho_mas

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Re: attention color whizes: non-typical sRGB/RGB/ProPhoto question
« Reply #218 on: January 04, 2011, 07:35:01 pm »

you think of one or another colour space. Now we are talking about both co-existing in the same scene. Ever wondered why shadows look blue while the whole scene is lit by sun?
and? I don't understand it (but would like to).
Are you talking about high saturated blues (captured with your camera) that you want to preserve (unaltered!)?
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joofa

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Re: attention color whizes: non-typical sRGB/RGB/ProPhoto question
« Reply #219 on: January 04, 2011, 07:38:25 pm »

The color AdobeRGB1998[0, 0, 255] does not equal XYZ [0.1881852, 0.0752741, 0.9911085] viewed in a D50 environment.

Mark I thought we agreed that XYZ=[0.188185   0.075274   0.991108] is outside Adobe RGB (D50) gamut but within Adobe RGB (D65) gamut in absolute terms. I don't know why are you getting confused.

Joofa
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