Quote Originally Posted by kevin klein View Post
The tests today have given very unexpected results, it seems that the speed of the plates has risen dramaticaly scince the last time.

The emulsion used was AG Plus with no additives, plates used are jappaned iron, and trophy aluminum with poly urithane coating. The first time I used a plate with urithane they came out fogged, but I think that was due to a different emulsion beeing used. This time I only made 4 plates so as not to waste material incase of chemical problems. The first plate was exposed at the same speed as the first trials, about .7,(f:11, 6 sc, overcast) the plate was extreamly fogged over and thaught...oh crap! But looking more carefully I noticed the corners where the plate was blocked from light had no fogging at all. This lead me to to the hopefull thaught that maybe, just maybe, the thing could have been over exposed, three more tries followed, each one with less and less exposure. By the time I got to the last plate the exposure was reduced to F:16, 1-1.5 sec. This translated to a speed of about .12, and still a bit over exposed and clear shadow areas.

The first exposures last week had been made at f:32, 8 sc. now its way faster. I dont know what is happening but it is good. More testing is needed, maybe the urithane on the two plates and the aspaltum japan on the other two had a sensitising effect when heated during coating and released sulphur ions(just a thaught). the emulsion had not been remelted over and over, it was transferred to a diferent container so small portions can be taken out and melted.

Things are getting interestinger and interestinger.
Correction, the speed should be 12 not .12