After repeating the prosedures several times here is what I have come up with using Rockland AG Plus emulsion coated on black aluminum trophy plate, coated with spray or brush on poly urithane varnish. Coat the back too so the aluminum will not screw up the chemicals.

Developer, Dektol diluted 1:1, plus 1gm Ammonium Thiocyanate to 3 oz. of working developer.

Exposure for tins,in my experiments have been f:45, 6 sec. overcast. This means a speed of about 12. for ambrotypes use only half exposure.

Develop 90-120 sec. It is a good idea to put a cover over the developing tray to keep the ammonia fumes from beeing a bother. rinse in water a few secons,( some say to go directly to fix ), Then fix about 10 min. in hypo.

Wash 10-15 min. then let dry. The image will darken a little when drying.

The images have all shown a little fog in the shadoe areas but it is'nt too bad. The addition of 1.5 gm Ammonium Thiocyanate to 3 oz. of developer will give a little brighter image but will also increase the fog a little more.

Give it a try.