Color science information

[JoakimZiegler]

I haven't posted much on RedUser before, but I've been working with Red cameras in various capacities for a couple of years, mostly on the postproduction end. I like Red cams a lot, especially workflow has gotten very manageable, and I think it's a huge advantage Red has over most other systems.

However, there's one thing that has bugged me slightly. While there seems to be new color spaces and gamma curves introduced fairly often (RedLogFilm seems to be a very good alternative to Log685, for instance), I miss having some precise info on what's actually going on. I'd love to know the primaries, white point, and transfer curves of the different color spaces, perhaps especially the most wide-gamut ones, so I could have more flexibility in conversion and matching.

Other camera systems (generally) publish this information, but I haven't seen anything from Red yet. While the work Nattress is doing on color spaces seems to be excellent and improving, I still feel those of us with more than a passing interest in color science are left a bit in the dark. Any chance of this changing?

 

[Andrew M.]

There are 242 search hits of redlogfilm and much more hits on redlog.

The idea was born from the discussion in here and the need for improvement.
If you follow the discussion you will see that not much was hold back but I agree you can’t find it in RED manuals.

 

[JoakimZiegler]

Yes, I have searched quite extensively (although I haven't read every result, so it's quite possible I'm missing something), and I see a lot of example images, a lot of people talking about how one colorspace/curve is more suitable for certain types of work, and I can certainly sit down and test that myself. As I mentioned, RedLogFilm seems very nice to grade from.

However, I can't seem to find any actual hard numbers, neither on the cameras' native primaries, or what the different colorspace/curves options actually do, expressed in numbers.

 

[Graeme Nattress]

REDLogFilm is designed so that upon Log2Lin in Nuke with default settings it will produce a linear light image which matches with our openEXR linear light export. Similarly, applying Lin2Log in Nuke on an EXR will produce an image that matches with a REDLogFilm export. The two export modes, REDLogFilm and EXR were designed together to work this way for combined linear light VFX and film-style grading workflows.

REDColor / REDColor2 are REC709 compatible in their colorimetry.

Graeme

 

[JoakimZiegler]

Ok, now we're getting somewhere, thanks.

So REDColor and REDColor2 use rec.709 primaries? If so, what's the difference between them?

 

[Graeme Nattress]

That's not what I said. They're compatible with REC709, but neither are REC709.

Graeme

 

[JoakimZiegler]

Ok, I don't understand what that means. Would it be possible to get coordinates?

 

[Dj Joofa]

I'd love to know the primaries, white point, and transfer curves of the different color spaces, perhaps especially the most wide-gamut ones, so I could have more flexibility in conversion and matching.

Hi,

I recently participated in two different forums regarding some aspects of color science. It is OT to what Red offers, but I was surprised at the confusion regarding a few basic principles of colorimetry and certain aspects of color science existing among many. The links are below. Outwardly, they talk about two color spaces, Adobe RGB and Prophoto RGB, but they contain tons of useful information on the proper interpretation of color spaces as contributed by many users, including some serious color industry and photography experts. Especially, please do check out the second link below, which expanded to about 35 pages of heated discussion:

http://forums.dpreview.com/forums/read.asp?forum=1018&message=37330104

and,

http://www.luminous-landscape.com/forum/index.php?topic=49940.msg411805#msg411805

The first link is for the background, and in the second link, which is not for the faint of heart , the real action starts a short while after the 4th or 5th message.

To avoid highjacking this thread, and reducing clutter, if you have any question on these topics please respond on the forums where the above links were posted and not here on Reduser.

Sincerely,

Joofa

 

[JoakimZiegler]

Joofa: Thanks for the links. I'm decently well read in color science, but they look like interesting discussions, especially for people who, as you say, don't have a good grasp of the basic concepts.