<< I use PMK for about 99% of my work so it made sense for me to use
this developer for the final enlarged negative. Ultimately it is not so
much the density range of the negative that interests me as the nature of
its characteristic curve.
I see.
>> I was not aware that you were trying to make the interpositve with APHS. I
did not try to use APHS for the initial interpositive because ....
I just want to make some tests so that beginners can use them it they want to.
Starters usually don't want to buy too many stuffs. :)
For actual work, I might use continous-tone film for the interpositive also
since the cost is not that much and one does not need to make it the final
size since enlargement is possible, so after my tests with APHS, I will also
do the test with continous-tone plus APHS.
The important thing is all this is fun! :)
>> BTW, in the information supplied by BS it is recommended that the initial
development of the interpositive in D23 1:3 be followed by 3 minutes in a
1% sodium metaborate solution. What would be the purpose of sodium
metaborate in this situation?
>>
The purpose is to increase the density range. D23 formula uses only sodium
sulfite as the alkaline, which is really soft. The metaborate is more
alkaline, so it allows the film to develop more.
If you want to increase the contrast, you could try 2% metaborate although I
don't know if it would actually help much because it also depends on how much
developer is absorbed in the emulsion.
To further increase contrast, you could use multicycle method, but that
involved processing in D23, then metaborate, stop bath, rinse, and that repeat
the cycle. I think if one needs to do that, he might as well try other
formula.
If you are processing the interpositive by a machine, I think it is easy for
you to simply develop it longer in D23.
Or you could try D76. Since it looks like you are mixing your own chemical, I
would suggest a modified version of D76 with the ratio of 1:1 for
metol:hydroquinone. The published formula has 1:2.5. Also, don't use the borax
version. Use the sodium metaborate version, and with some dilution, you should
be able to achive the range that is suitable for enlarging to the 2nd stage.
Dave