Inside the booth
Keep hair readable against the booth background
Compare the silhouette as well as the face.
A clear face can still lose the shape of hair against a busy or similar-toned backdrop. A small environmental change can make the portrait easier to read.
Test the actual hair and backdrop
Make a sample with the person in their intended position. Look along the outer hairline and around the shoulders. Do not remove an important hairstyle merely to simplify the photograph. Try the image in the chosen booth treatment before deciding whether the separation is enough.
Simplify the surroundings
Compare a plainer background or a small change in the person’s distance from it. Keep the light comfortable and equipment safely positioned. If using automatic background replacement, inspect fine hair edges in the exported result rather than assuming that a pleasing preview guarantees an accurate cut-out.
Keep a source without the effect
Save the unaltered photograph when trying a new background treatment. Review all frames, since a turn of the head can change the result. Choose the version the sitter prefers and keep creative background changes separate from a documentary copy of the original booth environment.