Roger Deakins has an online forum.  Where he responds to things you ask him.  About whatever.

Someone asks about one of the final sequences (spoilers in the actual post) in ‘True Grit’, “I couldn’t tell if it was green screened or if you had actually put a camera on a horse… but there was something definitely a little weird about it.
The same with the profile of the horse head shots. It looked almost animatronic and was lit very oddly…
It’s a sequence i can’t get out of my head it bothered me so much. Could you explain what was going on with that sequence and clear my mind of these silly questions?”

Mr. Deakins gives a thorough response ““Not silly questions at all. That was a very difficult sequence, much of which had to be done on stage for purely practical reasons rather than aesthetic ones.
A variety of techniques were used.” and then goes into breakdown of the shots including VFX, lights, gear, and lenses.

Or something on the lighting diagrams (which Mr. Deakins has already posted) for ‘No Country For Old Men’:

“Hi Roger,

May I ask you some questions about the street scene labeled Las Vegas from your diagrams? How did you use the source 4′s on the street lamps and how did it look like on camera. Was it pools of light? Also on the other diagram you have the platform with a lamp attached to it, above a street light. Was it to simulate the street lamp or to make it more punchy? Does the gel combination Half CTO/Straw give the street light effect with daylight or tungsten? Sorry for so many questions, but I find shooting under street lighting is so awkward normally and any guidance would be appreciated!!

Tony”

Mr. Deakins responds “Yes, shooting under street lights is difficult, especially if you are doing a long sequence with many angles as we were in Las Vegas, New Mexico (we could have gone with natural light in L.V., Nevada).
The source 4s were used two to each pole. With wide or medium lenses they were mounted each side of the existing street light with the lens in line with the top of the diffuser. No doors were used and gels were clipped to a gel holder. Being open like that the gels would hold if the lamps were saved between takes. The effect was to give a soft pool of light which extended the light from the existing fixture and we usually has the source 4s back to a dimmer and lowered the intensity so as not to overpower the existing light. The CTO and Straw gel matched the sodium colour quite closely. The camera wouldn’t see the lamp on the far side and the near lamp would become look as if it were part of the existing fixture. We did the same trick on the Border Crossing with 1.2 HMI Pars and we also did the same trick on ‘The Man Who Wasn’t There’.”

There’s more to both those posts, and so much more on those forums.  Maybe I’m not aware of them, but I can’t think of any other forums where someone who delivers the work Roger Deakins delivers is that open with his time and technique.  You can ask him about composition, style, lighting, camera settings and he goes so far to give you lighting diagrams.

What a resource. And the forum is pretty great too.