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

[jeremypayne]

Iliah,

I have great respect for your intellect ... but who would ever want to have a scene-referred color-matched shot at night in Times Square?  It may be an extreme example of mixed illuminants, but who cares?

When I shoot in a place like that, I worry about a pleasant image ... not color-matching a memory.

What's your point?  Where is modern color-managed photographic workflow letting you down?  I find the current crop of tools MORE than satisfactory - expecially when compared to the world of film and chemicals.

[Iliah]

I know C1 and the colour management strategy they adopted. However I do not know if they are working on adopting a more modern one. Some other companies are certainly do however. The problem is that colour management developed for scanning and printing is rooted in the minds of digital camera users and changing it means a significant commercial risk for a well-established company.

[joofa]

Uh huh...so for the purposes of transforming an image currently in Adobe RGB (1998) to ProPhoto RGB, ALL of the colors within Adobe RGB (1998) will get mapped to, and fit within, ProPhoto RGB without any clipping?

I think it's been demonstrated now multiple times that a slanted strip of colors in Adobe RGB (D65) from around blue to white has no direct linear representation in Prophoto RGB (D50). As an example an image pixel which is normalized ([0,0,1]) in Adobe RGB (D65) is out of bounds of the gamut of Prophoto RGB (D50).

Joofa

[sandymc]

Some other companies are certainly do however.

Who and what?

Sandy

[Iliah]

> but who would ever want to have a scene-referred color-matched shot at night in Times Square?

Architects, in my case.

> What's your point?

My point is we are on the edge of HDR displays being commercially available.

> Where is modern color-managed photographic workflow letting you down?

Modern colour management is not limited to the intents discussed in this thread."Classical" colour management is not letting me down because I know when not to use it.  On a side note, funny enough that Munsell's original ideas of colour are much better than what "classical" done while distorting Munsell's space to save on calculations. We do not need those simplified formulae anymore because we have powerful computers instead of rulers.

[joofa]

Hi Bill (Bjanes),

You can contain Adobe RGB (D65) in another variant of "Joofa Space"  , i.e., Prophoto RGB (D65). And, I mentioned that a number of times including my first note, case (2) below, because it is a larger space:

Joofa wrote on DPReview:

Fraction of unit stimulus blue ProPhoto RGB primary needed to match unit stimulus blue Adobe RGB primary:

(1) Adobe RGB white point=D65, ProPhoto RGB white point=D50, Fraction needed=1.2

(2) Adobe RGB white point=D65, ProPhoto RGB white point=D65, Fraction needed=0.91

(3) Adobe RGB white point=D50, ProPhoto RGB white point=D50, Fraction needed=0.88

(4) Adobe RGB white point=D50, ProPhoto RGB white point=D65, Fraction needed=0.67

I don't know why Prophoto was standardized at D50 and not at D65.

Sincerely,

Joofa

[Iliah]

Who and what?

Sandy

Here is one of the examples http://www.cis.rit.edu/fairchild/

[sandymc]

Here is one of the examples http://www.cis.rit.edu/fairchild/

Not quite a company , and looks fairly conventional at a first glance, but thank you anyway; I'm always interested in anything new in color management.

Sandy

[Iliah]

> Not quite a company

But your question was "who and where".

> looks fairly conventional at a first glance

May need a study, not a glance.

> I'm always interested in anything new in color management.

This is not even "new".

[jeremypayne]

Here is one of the examples http://www.cis.rit.edu/fairchild/

Guess he chose not to use such techniques as you describe on the home page image!

(I can't even imagine what that would look like if he had ...)

[joofa]

Your mistake is to transform Adobe RGB to ProPhoto RGB without white point scaling. It seems you are not interested on colors, but only on numbers.

Let me try to explain what are you doing:
we know that
- 1 inch=2.54 cm.
- now we are free to fix the unit of measure, and we say that 2.54 are meters (we are going from cgs reference sytem to MKS reference system without scaling)
- conclusion 1 inch=2.54 meters

JBrembat, I have said that a number of times, and I don't know why the point is not getting across that when you go from D65->D50, the length of the "unit stimulus/vector" changes. 1 inch no longer remains 2.54cm!

Sincerely,

Joofa

[Iliah]

> Guess he chose not to use such techniques as you describe on the home page image!

What type of chromatic adaptation do you see on that image?

[jeremypayne]

> but who would ever want to have a scene-referred color-matched shot at night in Times Square?

Architects, in my case.

Would seems a bit like tilting at windmills .... for a commercial product shot in the studio, I get it.

But, trying to color match Times Square at night "accurately" ... seems about as pointless - IMO - as most of this thread.

[joofa]

but who would ever want to have a scene-referred color-matched shot

Isn't the direction ILM is taking with EXR in the direction of scene referred color representation instead of output-referred spaces such as Adobe RGB? Its been a while and I have to look into it again that what was it about?

Sincerely,

Joofa

[jeremypayne]

> Guess he chose not to use such techniques as you describe on the home page image!

What type of chromatic adaptation do you see on that image?

Would appear that all three images (there are three) were shot with the same film/lighting - or - were digitally processed using the same white point - perhaps to match the combined spectrum of the refracted colors on the wall.

In essence, there is no chromatic adaptation mimicked in the image ... or just one ... an adaptation to the single white point.

Here in the room, I'm currently adapted to the white point of my monitor a I have been staring at it for hours.

[Iliah]

> there is no chromatic adaptation mimicked in the image ... or just one ... an adaptation to the single white point.

So this image does perfectly illustrate what I'm talking about (I would have taken it differently, in a one shot - but that is beyond the point).

[sandymc]

But your question was "who and where".

Let me remind you what you said in post 282: "Some other companies are certainly do however."

Your words.

There are uncounted numbers of academics all with a "better" idea, almost all of which will never go anywhere beyond a clever Phd thesis. Not the same as a company actually building real products.

Sandy

[joofa]

Joofa, correct me if I'm wrong here and stepping over my bounds.  I learned some interesting things from this discussion.

Hi TGray,

You are not stepping over any bounds. And, thanks for understanding what I tried to say. I'm glad that you learned some interesting stuff. The traditional approach to colorimetry has hampered its growth. But there are now some great insights developing borrowing from the areas of signal processing and linear algebra. Stay tuned.

Best regards,

Joofa

[Peter_DL]

> Guess he chose not to use such techniques as you describe on the home page image!

What type of chromatic adaptation do you see on that image?

Iliah, - would you have any images for illustration to make the point here ?

Peter

--

[jeremypayne]

> there is no chromatic adaptation mimicked in the image ... or just one ... an adaptation to the single white point.

So this image does perfectly illustrate what I'm talking about (I would have taken it differently, in a one shot - but that is beyond the point).

I don't get it ... one shot processed at "daylight" (or whatever) with today's tools would produce that result, no?