I would like to amend this post a bit.  Coral no longer carries ImagOn and I no longer know of a source to buy small amounts to try out.  Unfortunate because it is such a great product for those who are fed up with PnP and/or who want to get fine detail.  I now buy from takachpress.com in a 12 inch by 15 foot roll.  I also have not gotten around to writing up a tutorial on how I do the exposure and developing, but I do have a link to a fairly similar technique by Nancy L. T. Hamilton.  Nancy uses Puretch which is essentially the same as ImagOn.

PurEtch is available from capefearpress.com.  Jennifer is a pioneer among printmakers.  She developed an excellent system for high definition imaging on metal,  and very generous with her support.   If you have a question you can't find the answer to on her web page, just call her.  She may not speak "enameling," but she knows etching.