When converting a black and white photo to color, people rely on historical research to determine the accurate colors to use. They consult diaries, memoirs, government records, and old advertisements to gather information on the colors that were used during the time period depicted in the photo. This research helps to ensure that the colors used in the colorized photo are as accurate as possible.
In cases where there is no historical information available, the artists who are colorizing the photo may need to guess the colors to use. This is an art form that requires the artist to select the most suitable color for each frame of the photo. They may also use their own creativity and imagination to come up with colors that fit the mood and tone of the photo.
The process of colorizing black and white photos has evolved over time. In the early days of film, colorization was done by hand, with employees literally painting every object in every frame one color at a time. Today, however, colorization is often done using digital photo editing techniques and artificial intelligence algorithms. These tools make it easier and faster to colorize black and white photos, while still maintaining a high level of accuracy and realism.