Hello Austin, TX. About approx. ISO's etc. There is no use to figure it. If you figured it with todays light, collodion mix, lens. Then tomorrow it would be different because as collodion ages, the sensitivity changes as well. My exposures just depend on what the light looks like. I do lots of Civil War reenactments, and exposure ranges from 1.5 seconds to 5 seconds.

Ty Guillory
www.tystintypes.com
Mineola, TX