So I finished drawing up my plate and it was finally ready to etch. I didn't realise that the pencil marks on the plate would show up in the final print since they don't when you use a stone. The first job was to remove them which we did using acetone. Then process is about the same as stone lithography. The main difference is that phosphoric acid is used instead of nitric acid.
First we chalked and gummed the plate, then used some 50/50 on the dark bits. We then left the plate for about half an hour. This is what the plate looked like after the first etch:
To start the second etch, we gummed it then wiped away the image with turps. Next we wiped it down with acetone. Usually at this point during stone lithography you would use asphaltum to wipe away the remaining image. Instead in plate lithography you use shellac or my tutors home brew version which is a combination of paint and button polish. You rub that into the image then run in the asphaltum. After that the image is ready to roll up and second etch.
After rolling up the plate I realised that a section which I wanted as solid black was more of a grey. I think that the ink I used when I drew up the image must have split. My tutor says that if I need to, I can counteretch it to get the black I want but that I should proof it first. I guess we'll have to see how the proofs show up.