This was a project that I decided to recently redo. As part of a final exam for a Photoshop course in college, I took black and white photos of my grandfather and painted colors onto them. I remember being really happy with the way the photos turned out. But looking back a few years later, I realize that there are some improvements I could make. I think it's great to be critical of past work. Because how can you grow as an artist if you can't find room for improvement?
The first and easiest change to make was to improve the quality of the original photo. The photos of my grandfather were scanned into a computer from a scrapbook. This photo of Abraham Lincoln is from the Library of Congress and it was easy to find a 4K scan of this photo (plus, it's public domain, so that makes things easier).
The next improvement I made was focusing more on the undertones of Lincoln's skin. The human face is made up of hundreds of shades of yellow, tan, red, blue, green, pink, purple, and more. I started with a base skin tone and added layer after layer of different colors. For example, red can be found along thinner parts of the face, such as the ears. Also, yellow is typically more present on the forehead and temples. Finally, there is a layer of desaturation around Lincoln's cheeks to emphasize his five o clock shadow. Going even further, light reacts differently around different parts of the face. Subsurface scattering occurs around the ears, nostrils, and eyelids. Adding some red and yellow into those areas is in line with how light passes through and scatters around those areas. To get realistic results, all of these things must be considered. Creating gradient maps is the easy part - using colors to bring the image to life is the hard part.
Finally, there were some touch-ups made in Photoshop and Lightroom for some finishing touches. I hope to do more of these in the future as I believe it is a great practical study of the way light interacts with color in photography.
Update! After practicing this skill, I was recently able to incorporate this into my job. Here is a photo of Thomas More University's past President, Father John Murphy.