I recently found this thread and it is an excellent one! In my opinion, having a contract protects us, the artists and the client at the same time. But I think telling the client that it is just a formality could help ease the pressure or give the client the mentality of "nothing to lose".

Unless I have reason to think that there will be a problem I normally don't have the client sign a contract or provide a deposit. So far my intuition has been correct and it's always worked well for me. The complete fee is due upon acceptance of the painting and that keeps the pressure off both artist and client. I sometimes do a rough sketch for the client, first, where composition is an issue. I always contact the clients as soon as the painting is blocked in on the canvas and ask them to come review it. Normally they don't see it again until it's basically complete, when we look at it together once more to see if there are any details that need to be massaged.

I do have my clients sign a release, however, once they accept the portrait. Here are two versions which deal with slightly different circumstances:

Version #1:

Portrait Release Form

Upon receipt of the portrait