Jorge said:
Since you are interested in semi stand developing, wouldnt it stand to reason that using the Metol variant with Pyrocat HD would be of greater benefit when using semi stand since it produces sharper negatives?
Which brings me to the question, have you done any testing with resolution charts? I am just curious, but I cant help to think that every time people say their negatives are sharper I always want to know sharper in relation to what?
A resolution chart, another negative, what?
I think the primary advantage of the metol version is with normal agitation. When you do stand development the phenidone version is already so sharp that more sharpness might not be very pictorial. Understand that very pronounced adjacency effects might not be desirable.
That said, one could probably increase agitation slightly with the metol version and get equivalent sharpness. I am guessing, for example, that four agitation cycles with the metol version would give similar results to semi-stand agitation. And the advantage could be more even development.
As for resolution charts, yes I have done some testing. In fact, lots of it. I have done the testing and compared the results with D76, D76 1:1, PMK, Pyrocat-HD, etc. using both normal dilutions and very dilute solutions for extreme minimal agitation. What have I learned from this? First, second, third, one must be extraordinary meticulous in this type of testing, since such things as minor difference in T dimension of film holders can have a dramatic impact on results.
I have also looked at the results form this resolution testing with a microscope, and with scans of the lppm charts. You learn from this, but there are always anomalies lurking in the background.
Could I actually prove anything from this testing. Yes, I could prove that PMK (1:2:100) and Pyrocat-HD (1:1:100) are sharper than D76 1:1 and Rollo-Pyro , when agitation type is similar. The difference is small, but clearly there. I could not prove that Pyrocat-HD is sharper than PMK, or the reverse.
In the end the best test for sharpness, IMHO, is to make an enlargement of 4-8X with the comparison developers, keeping everything as similar as possible, and then have human being evaluate the results from some specified distance.
Sandy