With respect to the developing times in AH-1 vs AH-15:
As Michael points out, the only difference between them is in the Elon content:
AH-1 has: 7.50 g/l Elon, 10 g/l Na2SO3, 4 g/l Kodalk
AH-15 has: 2.50 g/l Elon, 10 g/l Na2SO3, 4 g/l Kodalk
So AH-1 seems as though it would be the more "powerful" developer. Yet in all cases (all 3 films) a longer development time was needed to hit the aim gamma.
An odd side effect is that the longer development (in AH-1) gave significantly higher film speeds (despite the similar gamma results). This might happen if, for example, AH-1 initially built low densities at a faster rate than the high densities. Then, after some extended time, the higher densities finally began to climb.
It's possible, too, that some odd sensi curve shapes were involved also. Determining gamma is not an exact process with a wobbly curve. Also, the speed point is not a fixed density in this test, they refer to the 0.3 G-bar method per standards at that time.
I'll type in another paragraph with their test criteria.
Last edited by Mr Bill; 12-20-2012 at 09:30 AM. Click to view previous post history.