Consider the film "They Shall Not Grow Old" in which WW1 footage was painstakingly restored and colorized. They went and found old uniforms and weapons to check

Consider the film "They Shall Not Grow Old" in which WW1 footage was painstakingly restored and colorized. They went and found old uniforms and weapons to check the colors. They went to the present-day locations to check the colors of the grass and trees. Etc.