Companies making color film
There were a wide variety of small companies who developed a color photographic process, particularly for movies. Usually they bought their raw stock from Kodak because EK was required by law to sell to its competitors, otherwise the government would sue EK for an anti-trust violation. All the classic Technicolor films, "Gone With the Wind", "The Wizard of Oz", "Snow White and the Seven Dwarfs", "Singing in the Rain", etc. were printed on Kodak release prints. Technicolor had developed a technique of dying a black and white release print into a full color release print. Technicolor did this for two reasons: 1) It wanted to be sure its release prints would run through a standard projector as well as a typical black and white film; 2) Technicolor used the same sound track as a black and white film. Typically Technicolor would print the sound track on black and white EK stock then DT the colors afterwards.
In the silent film days Technicolor appears to have manufactured its own film. The 1926 color film "The Black Pirate" with Douglas Fairbanks was shot with a special camera which recorded two-colors, called red and green, one every other frame. The camera negs were then step printed on to 70 mm stock, red images along the right side and the green along the left. The film was processed in some manner (relief matrixes? dye mordants?) and then the right side was dipped in a trough full of red dye and dried; then the left side was dipped into green dye and then dried. Next the 70 mm film was folded in half down the middle so the green image would overlay the red image in register. The two sides were glued together to form a 35 mm film which was run through the projector. Unfortunately, the film would peel apart and jam the projector. For this reason Technicolor developed the DT method.
In the silent era some companies hand painted their films; some used stencils; some used a rotating color wheel with red and green filters which rotated in synchronization in front of the projector lens. When sound came in some companies used a "bi-pack" camera, sandwiching two pieces of film face to face and running them through the camera as if they were a single piece of film. The front element was transparent and dyed yellow. It was sensitive to blue light but let red and green light pass through to the rear piece of film. Fox Studios produced such an experiment in 1929(?) which I saw: it was printed in blue and a ruby red--very natural. The Marx Brothers appear in a rare two-color process (on Youtube?) That would have been Paramount Studios. Brewster Color used dye toning; some examples of cartoons are on Youtube. Gaspar Color used a dye bleach method. He lacked a camera which would take separation negs, so his only US work is in stop motion, the "Puppetoons"--the most famous is "Tubby the Lonesome Tuba". This was a three-color process. I think Gaspar might have had his film manufactured in Europe. I don't believe he used EK materials.
Wikipedia has a good discussion of color cinema companies.