Movie Colorization Technology

I’m not sure where this question belongs, so I thought I would start here. :slight_smile:

Here’s a link to some colorized snippets that were posted on YouTube from the Beatles’s movie A Hard Day’s Night which was originally shot in black and white to keep the cost down.

I have two questions:

  1. How did they do it? With old b/w photographs back in the day they had to painstakingly hand color the negatives, but I assume there’s now an easy way to digitize it and color it using a kind of Photoshop for film.

  2. How accurate are the colors likely to be? I assume the colors were chosen by the technician that did the colorization unless they had some reference photos to work from. It looks real enough to me, but that may just be an illusion.

Wow, that was genuinely terrible. All you have to do is watch HELP! the next year to see how the Beatles in color ought to look. Don’t know how high-end the tech is here, but the plastic skin tones are a dead giveaway, as is the lack of shading or texture in most of the brighter colors. Blech.

Most of the time, the colors would be guessed by the tech performing the process. For movies, using color stills of action on the set for reference is pointless because often (on sound stages more than location), something would be chosen because of how it looks in B&W, so using the color it really was defeats the intention anyway.

Can’t speak to the actual colorization process, but a lot of it is computer-based, of course, and has been since the technology first emerged (and roundly criticized) decades ago.

What was the process when it was first invented?

Ah, sepia skin tones. Very realistic.

The 1954 Frank Sinatra movie Suddenly was colorized by Hal Roach Studios in 1986, and the colorist must have misheard Sinatra’s nickname as “Ol’ Brown Eyes,” because that’s what color his eyes turned out as in the colorized version.

Very small paintbrushes, a steady hand and lots of time. Going as far back as 1895, the first colorized movies were done frame by frame by hand, and that’s pretty much all there was until digital colorizing was developed in the 1970.

In broad terms, the colorizers would break the movie down into scenes and even further into shots. This would let them define a shape in a frame of film as sky, a car, a face, etc., and once they assigned a color to it, the computers can then identify the object as it will be in more or less the same place from one frame to another, add the assigned color and repeat the process to the other frames. Lather, rinse, repeat…

Whoever did this Beatles one is under the impression Paul McCartney has blue eyes.

It’s a technique known as rotoscoping, where the VFX artists draw around the shapes in the frame in flat colours*, then advance a few frames later and move the shapes to match, and the computer will draw in-between frames as best it can, which then have to be corrected by hand if it isn’t a match.

Basically It remains as painstaking as ever, maybe more so as they have to take into account things like moving hair, motion blur, transparency like glass and plastics, and high definition details.

*The black-and-white footage takes care of subtleties like gradients and shadow.

At least they didn’t do one thing I have seen in early colorization attempts. They would sometimes leave the darker area in the background as the original black and white rather then go to the effort to color them in dark shades of various colors. It stands out like a sore thumb, color action against B/W background.


Not completely true. Because these films were mass-produced, they did develop faster ways to do the specialized coloring: Stencils. A strip of film would be cut, frame by frame, to expose the area that needed to be colored. These might be several feet long that you would then overlay on the film which needed colorizing. Here’s a picture of a sample few frames of a stencil.

True, while cutting the pattern out of each frame was time consuming at first, once that was done, then you could paint several feet in a matter of seconds with a normal brush. For films with multiple colors, multiple stencils would be used, a different one for each color.

The modern version does attempt to pattern match, and let you keep the colors in between frames if it looks like the same object. It’s nowhere near perfect, though.

And, of course, it still looks like crap if you don’t know how to handle human skin, or that most objects have more than one hue to them–different for the shadows and highlights.

I’ll do photos occasionally, but not video. But I did look into it and talk to some people.

B&W film and video doesn’t have enough information to create a color version of the images. We look at B&W and our brains fill in a lot of detail that isn’t there. Colorizing is advancing to the point of generating new information to create more realistic skin tones and color variation in shading but it’s doing the work of an artist to create new images based on what we expect to see. Eventually we won’t be able to detect whether a work has been colorized with the naked eye but we’re not looking at the image that would have been shot in color in the first place.

The early colorization processes whether automated or manual combined the use of paint by number techniques for important details like the color of clothes, hair, and significant props and then a one or two colors over the background. What’s advancing is akin to the use of surface maps in CGI where the shape of the detail is not as significant as creating realistic to the eye details of the coloring of the shapes that have subtle variation in color and shading to look like real images instead of 2D cartoons.

The results will remain disappointing in many cases. B&W images weren’t shot to be colorized in the first place. High contrast lighting was a characteristic of good B&W images. Actors were heavily made up to wash out features not enhance them. The best B&W film suffers from colorization, but a film like A Hard Day’s Night wasn’t that kind of quality image anyway (at least not the version I recall seeing at the theater or later on video). It was filmed quickly in documentary style. Current colorization techniques won’t do much to enhance the imagery except for using more colors, and detract somewhat from the reality of the times viewed mainly in B&W by people on TV. I’d say leave it alone myself, but apparently people who weren’t raised in the old B&W world can’t stand to see B&W. The Beatles only existed in shades of gray when they first appeared on Ed Sullivan an Hard Day’s Night. Even the Beatles trading cards available at the time were mostly B&W photos. And as the world turned to color the Beatles presented their own image in enhanced color and cartoon style to fit the emerging 60s day-glo era. I dread the day that we see a colorized version of Raging Bull and other great works of B&W art.

I was under the impression that rotoscoping is tracing over the image of a live performer, frame by frame, in order to get realistic motion in an animated character. For example, I’m pretty sure it was done for the performer singing “Oh, Wolfie” in “Red Hot Riding Hood.”

Steps are being taken in the direction of AI-based colorization.

Even for B&W films, there are usually still photos of the actors in test shots for the costumes, hair, and make-up. Although, that doesn’t always tell the whole story. Sometimes colors didn’t show up right under harsh studio lights on B&W film, so the “wrong” color was used. Most costumes that were meant to look white (and did) in B&W films were actually light pink, so a still of an actor in a light pink costume would tell the colorizer to leave it white. Stage blood didn’t look right either. There’s a famous anecdote that chocolate syrup was used for the blood in the shower scene in Psycho, and it’s reported in many reliable sources. I don’t see any reason not to believe it. It wouldn’t surprise me at all that stage blood “washed out” under the lights (a lot of formulas involve Karo syrup and food dye), and then since the color of whatever was used was irrelevant, brown would actually play better than red in a B&W film.

But at any rate, there are lots of sources for the original colors of things, and sometimes the designers notes on how things were supposed to look. In the silent era, little was preserved, but by the time of the studio system, memorabilia was a business, and all kinds of minutiae from various stages of production were saved-- not to mention, a generation had already passed of the film industry, and people were interested in its history.

The computerized technique of doing the same thing is also called ‘Rotoscoping’ by some. The computer figures out the outlines of live performers and fills in the colors.

Correct, that’s where it was initially used. It’s for any kind of tracing of live action. In visual effects it’s most often used to cut out individual items and characters on film so you can slip new elements in front or behind, amongst other things, but it’s also used for creating post-produced 3D, and colour grading, which includes colourising a B&W film.

Here’s an example of what modern rotoscoping looks like.