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  • Hey all, just changed over the backend after 15 years I figured time to give it a bit of an update, its probably gonna be a bit weird for most of you and i am sure there is a few bugs to work out but it should kinda work the same as before... hopefully :)

RedColor3 Gamut

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F. Malmer

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What is the RedColor3 Gamut? In other words, what are the CIE coordinates for the three primaries? Graeme?

How does it compare to sRGB and Adobe RGB? What is the difference between RedColor2 and RedColor3 in terms of gamut?

When I export, is it all converted to sRGB and lots of color-data is thrown away? Does the TIFF color profile setting do anything on export other than change the TIFF metadata?

If RedCine-X internally is CIE-space, then is it possible to save it in CIE-space aswell? Or atleast choose output gamut?
 
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REDColor3 is our current best method of developing our camera RAW data into REC709 / sRGB colour space.

Graeme
 
The camera gamut itself is immense, but as you realize, as long as you're not clipping colours you can use whatever primaries you want and not have a reduced gamut.

Graeme
 
That would be great...! How does it relate to REC709? Is it bigger smaller? P3?

We're talking more and more about CS and wide gamut with the advent of the F65 and the upcoming F55... Where are we taking these images when we dial in Redcolor2 or Redcolor3. Are they wide gamut CS that are worth archiving in ACES format?

It would be great to get some charts on how it relates to other colorspaces!

Thanks
 
Graeme Nattress said:
The camera gamut itself is immense, but as you realize, as long as you're not clipping colours you can use whatever primaries you want and not have a reduced gamut.

Graeme
Click to expand...

Would be really, really good to know what the camera gamut is for capture.
 
Camera gamuts are wide, and not particular easy to plot out the way a monitor display gamut is. When you see a camera gamut plotted as a triangle, that's usually a sign that something funny (or misleading) is going on.....

Graeme
 
OK, good to hear.

Personaly Ive never had any issues with captureing any colour with our Epic's. Some others seem to have but Im not so sure its a capture issue and more likely to be some sort of poor workflow. There are a couple of observations I read about Sony's sensors being prefered for colour in some unspecified way, but Im not convinced.
 
Not convinced myself either - take a critical look at their diagrams and compare them to known colour space diagrams and tell me what you find :-)

Graeme
 
Graeme Nattress said:
Not convinced myself either - take a critical look at their diagrams and compare them to known colour space diagrams and tell me what you find :-)

Graeme
Click to expand...

OK - I'll play: because gamut is a 3D thing, not a 2D thing... that triangle expresses only a best-case scenario.

Digital may beat film in bright saturated colors... but because negative film works the opposite way to digital, 35mm negative film still has the edge on the F65 when it comes to dark saturated colors? That's the way it is in projection currently so I'm guessing that carries across to acquisition too.

And Sony's chart doesn't express this.

I do wish that RED would post stuff but I guess it's confidential and / or there is something in the colorimetry you guys don't want to publicize with the Mysterium X. I do hope that with Dragon you guys will be so proud of the color that you post more technical info.

In either event, I'm looking forward to doing some proper tests next year between Kodak, Fuji, RED (Dragon), Sony and Arri, openly, with RED's input on best practices.

Primary goal of course is to see if it's possible to create a way to transform skin tones shot on RED Dragon to a look similar to Kodak or Fuji or, heck, a good DSLR under various lighting conditions.

If the original color information is there (eg the sensor recorded the colors purely), then that should be possible. Or hey - maybe they will look great out of the box and no transformation will be needed!

Bruce Allen
www.boacinema.com
 
Bruce, what you say is interesting enough, but that's not the particular issue I am getting at with the published Sony diagram. You need to take their diagram and overlay known colour spaces over to top to see if what they label is actually plotted correctly....

The other issue is in the diagram I saw, they labeled a gamut DCI, and as far as I know, DCI uses XYZ.....

Graeme
 
Graeme Nattress said:
Bruce, what you say is interesting enough, but that's not the particular issue I am getting at with the published Sony diagram. You need to take their diagram and overlay known colour spaces over to top to see if what they label is actually plotted correctly....
Click to expand...

Oooh! That's hilarious! OK - will try :)

Graeme Nattress said:
The other issue is in the diagram I saw, they labeled a gamut DCI, and as far as I know, DCI uses XYZ.....
Click to expand...

I took "DCI" to mean "here is a best-case triangle of what DCI's current projector standards are - eg if you master for digital cinema, these are the colors that will show" which seemed to me to be at least semi-relevant.

Anyway, cool - will get through my deadline then chart some stuff :)

Bruce Allen
www.boacinema.com
 
Let me know what you find, Bruce.

Graeme
 
OK, does anyone want to help me confirm the actual Sony F65 primary chromacities?

According to this document:
https://www.servicesplus.sel.sony.com/Downloads/SoftwarePLUSReleaseNotes/Release-Notes-F65RVM100.pdf

Sony puts their S-Gamut reference primaries as:
Red 0.730 0.280
Green 0.140 0.855
Blue 0.100 -0.050

But that's not the same thing as the camera's own real-world color sensing abilities.

What is interesting though is that S-Gamut is really, really close to the ProPhoto primaries, and kinda in between the ACES primaries and the UHDTV primaries.

This makes me think that this must definitely reflect in some way the sensor's actual response. Because if it is just a theoretical space, why not just go with an existing wide-gamut standard (ProPhoto, ACES, UHDTV)? But then... maybe they just took ProPhoto and modified it to make it "Sony" ?

The real answer is that someone just needs to make a nice wide-gamut scene and see how the darn thing responds!

Lemme see a little more...

Bruce Allen
www.boacinema.com
 
Bruce Allen said:
But that's not the same thing as the camera's own real-world color sensing abilities.
Click to expand...
That is correct for sure. Cameras are not colorimetric devices, so don't have well defined primaries.

Graeme
 
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