I have a question regarding the value of a copyright buyout for a custom font. This subject has come up earlier on Typedrawers, but this case is a bit different. Here is the situation:
I made a set of highly specialized custom fonts for a client under five-year exclusive licenses, with all the usual restrictions. Before the license period was over, the client, who sees the fonts as essential to their identity and future work over the next decade or two, expressed the desire to buy all rights to the fonts.
On what basis does a designer establish the value of such a sale? Is there a formula that is customary in the type industry? If so, how does the type designer document this custom? Does anyone have cases I can cite?
Thanks in advance.