The problem with heavily modifying a formula is that it isn't that
formula anymore.
I don't know what is in FX-39 so its difficult to predicet the
effect of Boric acid. I've never seen it used in another formula.
In general lowering the pH of a developer will reduce its activity
but it may also affect other properties. In the case of D-76, in its
buffered form, or other buffered developers like Microphen, the
buffering is adjusted to about the same activity as an unbuffered
formula. In some older developers, like Kodak D-61a, an acid is added
to adjust pH as well as to add some buffering.
If your developing times are very short I suggest using another
developer of less activity. Delta 100 in D-76 1:1 or in Xtol 1:1 should
give you times long enough to shorten them for contrast adjustment. As
a rule of thumb standard emulsion films cnange about one paper grade
with about 33% change in development time but core shell films like
Delta or T-Max need only about 20% to 25% time changehe same contrast
change. I think, in fact, this is why many photographers have problems
with these films.
There are even less active developers. For instance D-25 requires
substantially longer time than most other developers. It is an
extra-fine-grain developer with very little edge/border effects so does
not produce "acutance" effects but diluted 1:3 it becomes an acutance
developer with quite long development times. At 1:3 it looses its
extra-fine-grain property and is about the same as D-76 but produces
full film speed.
Richard Knoppow
Los Angeles, CA, USA
dickburk@ix.netcom.com