You are doing very well with your English. Much, much better than I'm doing with learning Romanian. Fact is that I know no words in Romanian. See, you are way ahead of me! We know that Boric Acid is used to kill ants and roaches that's the 99%. We are just curious what the other 1% might be. Of course it might not be just one thing or chemical, but it might be a compound of things. They might all be good or some might be bad or all of the 1% might be harmful to the film emulsion. I don't think it would be bad and I will find out next week when I make two batches, (one with roach killer and one with pure Boric Acid) and try them out. JohnW