Color timing has always been a part of the film making process, from the earliest days of color technology. It is the process used to see to it that the final film has a consistent look from shot to shot and the color palette of the film overall matches the vision and goals of the director and cinematographer, to the extent the technology, budget and schedule allows.
In recent years, the extremely arcane early forms of color timing has been replaced by digital processes, including the "digital intermediate" and the uses and abuses of the 3D color lookup table, a tool that can be used for both good and evil, which is true for pretty much all tools.
But in earlier, more primitive days, the process of color timing was less exact and had more issues because it generally involved sending tests and film to the lab and seeing the results the next day. But the system worked, it worked well, and some of the most fabulous films in the history of cinema used these now archaic processes.
There are some funny stories, however, and this is one of my favorites. To understand the story, you have to know something about makeup effects, some of the reasons they are so helpful to the film making process, and also something about the difficult schedules associated with episodic television.
Makeup effects are a form of special effects that are based on the theatrical art of makeup. Although the technologies behind it continue to advance with new materials and new approaches, it has a history that goes back directly to the earliest days of stage. Most of the use of makeup is not for special effects however. All actors seen on stage or on film wear makeup to make them look natural under the very unnatural lighting and to achieve certain effects depending on the distance of the audience and, for film, the effects of photography on the end results. An actor that did not wear makeup would often look incorrect and take away from the story. This is a very important part of the normal film making process.
Less often used, although it seems to be used a lot these days, are makeup effects which attempt to achieve something outside the normal process of makeup. The classic examples are vampires, with their teeth, or Vulcan's with their pointy ears, and so forth. Pretty much all of the classic villains of Batman have used makeup effects of one type or another to achieve what is special about their character. One of my favorite characters in the recent Guardians of the Galaxy is a young actress whose outfit seems to be blue makeup. One of the great advantages of makeup effects is that once they have been photographed, and then color timed, you are (hopefully) done. No more post production necessary or that is the idea.
But films and television did not always have so many green or blue women, and people were not always so used to seeing them, and this is my favorite story about such things.
A long time ago, episodic television was shot, and still may be shot, on a brutal schedule. Each hour long episode needed to go into production with a script, and be completed in one month, on film, which was then broadcast. There were usually four episodes in production at any one time. This usually meant that each episode had one week on the stage with the actors for shooting and three weeks for post production. There were exceptions to this rule, and the process made allowances for special episodes and special problems. But it could not do so indefinitely, and when they screwed up they had to repeat an episode or do something else they did not want to do, and it was a big deal.
An episode in the third season of the first incarnation of Star Trek involved a very well known young actress and dancer, Yvonne Craig. Although best known for her role as Batgirl in the original TV series, she was also an alumnus of the Ballet Russe of Monte Carlo, and among other things, the famous green exotic dancer and slave girl in an episode of Star Trek. This story comes from what happened when they shot that episode.
Now at this point we are nearing disaster. The episode can not keep on just shooting as long as it wants, it pretty much has to wrap within a day or two. But someone got the bright idea to call the lab and ask if anything unusual was going on that might have caused this. Perhaps that is the first thing they should have done, in hindsight, but it did not occur to them, or so the story goes.
And it turned out that the lab was convinced that the green dancer they were seeing was some sort of mistake they had made in processing, that of course the show would not have shot a nearly naked woman in full-body green makeup, and so they color timed the result to make it looks as much like flesh tones as they could and hoped it would be good enough. Today of course we would not blink an eye at green exotic dancers who are also Orion slave girls, but those were a more innocent time.
Anyway, the problem was solved, and one of the more famous sequences involving Star Trek's sexist exploitation of women was famously born.