I've had that link (one-step direct negative by reversal: http://unblinkingeye.com/Articles/NbyR/nbyr.html) in my favorites for a year now, but for whatever reason haven't gotten around to seriously considering trying it. I'm glad you reminded me. I have sodium sulfite, of course, and even potassium dichromate (for gums, which I haven't done yet), but where would one get sulphuric acid? Could it possibly be had locally, or would one have to order it online?