Thursday, March 17, 2011

good iso

Some things to know about:
Make an exposure bracked test first thing; it is worth it.
Mix fresh Dektol; it only last about 4 months; dilute it 1:3; that is, one part Dektol ane three parts water; develop between 3/4 min and 4 min maximum.
Unexposed or undeveloped emulsion will be white; it will clear in half an hour in fixer; you can see it happen in a black tray; nothing will happen for 15 min.
Exposed emulsion will turn black; you can watch it develop in a white tray; it will darken within 30 seconds.
Stop bath may be in a red tray; you can see red in low light; it may be fresh fixer, although much less than in the fixer tray; slosh it for 30 sec.
Washing for 15 min is not too much
emulsion will stick to properly cleaned glass even if in liquids for 75 min
ISO will increase with age of emulsion even in the bottle; the longer emulsion is warm the higher ISO becomes; the hotter the higher; it will fog

My old emulsion that was allowed to sit on a warming plate was used as an ISO of 10, and was developed for 3 3/4 min in Dektol 1:3
In order to lower development time into the center of the time range or about 2 1/4 min the developer would need to be more concentrated.