Over the years, some digital camera manufacturers have touted their products by saying that the pictures made with their wonderful cameras had a “film” look. I recently encountered something I wrote elsewhere on that subject that may have some contemporaneous relevance now that yet another vendor is making similar claims. I am reproducing it here.
I’m not knocking the talents of the brilliant chemical and industrial engineers at Kodak, Agfa, Fuji, and many other companies. It’s just that it is really hard to produce a film/processing — in the case of ‘chromes — and film/processing/paper/processing — in the case of color negative films and papers — system that produces accurate color. At SPIE meetings Ed Giorgianni, a Kodak engineer of some repute, used to give seminars on the details of the color processing of film-based systems. I would walk out shaking my head, amazed that film did as well as it did considering all the really tough chemical problems involved.
I once did an experiment where I took 25 different ‘chrome emulsions (this was in the 90s, when there were lots to choose from), shot a Macbeth chart, and read all the resultant patches with a spectrophotometer. The average CIEL*a*b* delta-Es were in double digits. By the way, the great thing about doing that experiment was smelling film canisters right after I opened them. I loved that smell, and miss it in the digital age.
The engineers working on film systems weren’t dummies. They knew they couldn’t make it accurate. There was a body of opinion that stated that you didn’t want it accurate even if you could do it. So they came up with many clever and artful inaccuracies that we call the film look. But it’s not one look, it’s a bunch of looks, and none of them are very accurate. Now we have digital systems, and we have fewer constrictions on what we can do. It’s still impossible to build practical systems for color photography with great accuracy, but what we have now is much better than with film.
My contention is that better color (upon capture) is more accurate color. We’d like color channel responses of the capture sensor to be as close to a 3×3 matrix multiply from the rho, gamma, beta responses of human cone cells. If accurate color is not pleasing color for the intended use, we can distort the color in post.
If you want to do a deep dive into color reproduction, start here.