Photo Licensing Questions

Back story: I shot and retouched a few photos for a very good musician friend of mine free of charge. I styled the shoot, and did her hair + makeup.  Those photos led her to a very sweet gig working overseas, making thousands of dollars, with free room and board for several...

Ugh.  Please advise this amateur who needs the proper words to respond to this email from the owner of the Record Label I've been working with regarding my contract/invoice for said work which they've just received.  He says:...