palplr wrote:
> Can any one say what are the easily avaliable photo checmicals to
> spray or paint on the bare pcb for either positive or negative print.
>
I don't think you can easily formulate our own liquid photoresists that
perform as today's commercial photoresists. Exact ingredients and
manufacture process would be a trade secret, and to get close you have
to be expert in that field of chemistry. Because you ask the question I
assume you have very limited knowledge of chemistry just as I do. Your
best bet is to study chemistry and search the patent databases.
Good luck,
Adam