There is no difference in the quality of the Chroma Key blue and Chroma Key Green. Some photographers and film professionals prefer green as it is less likely to match any colors that might occur in the subject, therefore making it easier to isolate the subject from the background in photo editing software. Others prefer chroma key blue as it is more versatile and can also be used as a regular backdrop (with out digitally editing out the background). Flat even lighting (without shadows or variances) should be used with both colors if you plan to edit out the backgrounds. If your subject is far enough away from the background then any form of lighting (including dramatic lighting) can be used to light your subject.