attention color whizes: non-typical sRGB/RGB/ProPhoto question

[joofa]

Does this accurately represent what you are getting at Joofa?

I didn't draw them the way you described. That approach has problems.

Joofa

[tho_mas]

Trust me it is the real representation of gamuts. With a great advantage of being in linear space. I can't overemphasize that fact.

There is no need to go into nonlinear Lab gamuts, such as those in the commercial programs presented here. In fact, though I could be wrong, and I have to verify my findings, but there is an issue of gamut being twisted in those programs but I was afraid to point that out. Because if I did, Digital Dog will be all over me, saying "how come you are right and these established tools have the possibility of being incorrect?"

I am totally open to new findings. If you are right: fine so. Then we've learnt a lot!
My problem is I have no clue (well, little) about the physics and maths behind all that stuff. But as a (not totally unexperienced) "user" I can't replicate your findings and it is also not in line with my understanding of color mapping / color appearance.

So, down to earth...:
I can create high saturated AdobeRGB blues (source) that clip in ProPhoto (target) when I convert abscol from AdobeRGB to ProPhoto (because, well, D65 light is "bluer" than D50 light).
But the inverse "test" doesn't work: all the blues (from the highest saturated blue to almost white) in ProPhoto (source) clip when I convert to AdobeRGB (target)... relcol or abscol, either way. How so... when your findings are right?

[MarkM]

I didn't draw them the way you described. That approach has problems.

That's not very helpful. I'm really making an effort here to help you get your point across, because you are not very good at communicating it.

These are orthographic projections at 90 degrees from each other. I can rotate it differently and project using perspective, but the data stays the same.

And the point stays the same. So my question is: is this what you are trying to say? Is this the argument you are making for the difference in gamuts?

[tgray]

I can create high saturated AdobeRGB blues (source) that clip in ProPhoto (target) when I convert abscol from AdobeRGB to ProPhoto.

Isn't that what he's been saying all along?

[joofa]

That's not very helpful. I'm really making an effort here to help you get your point across, because you are not very good at communicating it.

These is an orthographic projections at 90 degrees from each other. I can rotate it differently and project using perspective, but the data stays the same.

And the point stays the same. So my question is: is this what you are trying to say? Is this the argument you are making for the difference in gamuts?

Mark I already said, No. You are not being correct here.

Joofa

[MarkM]

Mark I already said, No. You are not being correct here.

Joofa

OK. What is the difference between what I have said and what you are saying?

[joofa]

OK. What is the difference between what I have said and what you are saying?

Mark, it is quite an involved issue. You want to go into the mechanics. It can take at least one entirely different thread, or several, as there are many issues here. I want to keep this thread on the track with the discussion of gamut differences between Adobe RGB and Prophoto RGB. So far it has surprisingly turned out to be very focused. Which is a marvel in itself. See about 22 pages and still focused.

Lets keep the issues in hand.

Joofa

[tho_mas]

Isn't that what he's been saying all along?

it is what you can see essentially here... comparing the gamuts both under different illuminants:
http://www5.pic-upload.de/07.01.11/gnhzegyold.jpg
that was already discussed somewhere 10 pages above...

But if I remember correctly "Joofa" claims that the high saturated blues of AdobeRGB are also outside of ProPhoto after gamut mapping (from AdobeRGB to ProPhotoRGB... incl. Bradford chr. adaption).

[joofa]

But the inverse "test" doesn't work: all the blues (from the highest saturated blue to almost white) in ProPhoto (source) clip when I convert to AdobeRGB (target)... relcol or abscol, either way. How so... when your findings are right?

Both directions are predicted by my findings and I have been saying all along, though I focused more on the (1) below:

(1) Adobe RGB (D65)->Prophoto RGB (D50) clips in abs col.
(2) Prophoto RGB (D50)-> Adobe RGB (D65) clips wheter relcol or abscol as you have observed yourself. <--- I have to verify relcol a little bit more, but abscol will certainly do.

Sincerely,

Joofa

[joofa]

But if I remember correctly "Joofa" claims that the high saturated blues of AdobeRGB are also outside of ProPhoto after gamut mapping (from AdobeRGB to ProPhotoRGB... incl. Bradford chr. adaption).

I never claimed that!

Joofa

[MarkM]

I want to keep this thread on the track with the discussion of gamut differences between Adobe RGB and Prophoto RGB.

That's exactly what I was trying to do. I used your argument (or at least your argument as I understood it) regarding the gamut plots and came to the same conclusion. But all you will say is 'it is quite an involved issue'? Do you not want people to understand you?

Again, I'm making a sincere effort here.

[tgray]

But if I remember correctly "Joofa" claims that the high saturated blues of AdobeRGB are also outside of ProPhoto after gamut mapping (from AdobeRGB to ProPhotoRGB... incl. Bradford chr. adaption).

I think his original claims were:

(1) Adobe RGB white point=D65, PropPhoto RGB white point=D50, Fraction needed=1.2
(2) Adobe RGB white point=D65, PropPhoto RGB white point=D65, Fraction needed=0.91
(3) Adobe RGB white point=D50, PropPhoto RGB white point=D50, Fraction needed=0.88
(4) Adobe RGB white point=D50, PropPhoto RGB white point=D65, Fraction needed=0.67

I have drawn case (1) in the image shown above. So, except (1) other modes offer a scenario where no clipping needs to happen. I.e., for (2),(3), and (4) the gamut of Adobe RGB seems to be contained within ProPhoto RGB, but for (1) the gamut of Adobe RGB around saturated blues gets clipped in ProPhoto RGB. Incidently, (1) is the standard mode of specification of white points for both Adobe and ProPhoto RGB. So, is standard specification of ProPhoto RGB saturation clipped near Adobe RGB blue primary?

[tho_mas]

(1) Adobe RGB (D65)->Prophoto RGB (D50) clips in abs col.
(2) Prophoto RGB (D50)-> Prophoto RGB AdobeRGB(D65) clips wheter relcol or abscol as you have observed yourself. <--- I have to verify relcol a little bit more, but abscol will certainly do.

so you (we) are still on the level of a D50 white is not a D65 white???
Sobering!

[jeremypayne]

Why is it so difficult to realize that both Adobe RGB (D65) and Prophoto RGB (D50) have colors that are outside each other's gamut? This was the premise of the whole exercise since a 2D representation of gamut as chromacity diagrams does not show that. Didn't I start from there?

Doesn't my plot show that clearly?

Joofa

Since this whole debate is about "colors" ... not plots, graphs or numbers ... I was hoping you could define a color for me.  Seriously.

[joofa]

Joofa wrote:
(1) Adobe RGB (D65)->Prophoto RGB (D50) clips in abs col.
(2) Prophoto RGB (D50)-> Prophoto RGB (D65) clips wheter relcol or abscol as you have observed yourself. <--- I have to verify relcol a little bit more, but abscol will certainly do.

so you (we) are still on the level of a D50 white is not a D65 white???
Sobering!

Hey, I had a typo in my text you quoted. I mentioned Prophoto at a place where I wanted to say Adobe. Please correct. I edited the original message.

Joofa

[Farmer]

Mark, it is quite an involved issue. You want to go into the mechanics. It can take at least one entirely different thread, or several, as there are many issues here. I want to keep this thread on the track with the discussion of gamut differences between Adobe RGB and Prophoto RGB. So far it has surprisingly turned out to be very focused. Which is a marvel in itself. See about 22 pages and still focused.

Lets keep the issues in hand.

So you're not prepared to explain the mechanics of how you got to your results, but you are prepared to suggest that other commercial programs and other well used utilities might be wrong (even though you say you don't know how they work)?

[Graystar]

Joofa, do you believe that colors are physical properties?

[jeremypayne]

so you (we) are still on the level of a D50 white is not a D65 white???
Sobering!

White is white!  And I think "white" is a color .... I just wish I knew what a color IS.

I think I know, but I want Joofa to explain it to me ... then and only then can I pick a "side".

I'm leaning towards the Adobe RGB blue primary IS inside ProPhoto ... but I can't decide until we agree on what a color is.

THAT'S back to basics.

[joofa]

So you're not prepared to explain the mechanics of how you got to your results, but you are prepared to suggest that other commercial programs and other well used utilities might be wrong (even though you say you don't know how they work)?

See, I don't need to know how other utilities are implemented. I said before also I was basing that on certain properties of the Lab space, which they use. And, I said I could be wrong. But, I have to verify it. How hard is it to take that I just mentioned a guess? It is not a legal forum. Why do you guys get pissed off on a slight mentioning of something along the lines I am thinking? 

Joofa

[MarkM]

See, I don't need to know how other utilities are implemented.

I'm not asking you to do that. I'm simply asking what the difference between my explanation and your is.