<< I don"t recall anyone mentioning D-19 as a lith developer. I use this
for photogravure positives with infreqeunt mottling. I use a 1:4
dilution with 1-2 minute developement agitating briskly the first five
seconds and vary the remaining agitation (usually slight every thirty
seconds) to vary the contrast. >>
D-19 is a very high-contrast developer! It is used for developing lith film
for lith effect. In fact, one can use it in the place of Kodalith. The
contrast wouldn't be as high as Kodalith, but it will work in many
applications.
Why do you want to use such a high-contrast developer for low-contrast
negatives? I speculate that you need high-contrast development somewhere with
the process, so it is convenient to use the same developer for both continuous
and lith development?
If you examine the composition of D-19, there is quite a similarity between
D-19 and Dektol (the published version). The ratio between metol, hydroquinone
and carbonate is basically the same. Dektol has a lower amount of sulfite,
which I don't think make much difference in our application.
However, D-19 has a much higher proportion of Potassium Bromide. The
restrainer restrains the toe so you get very steep curve. With dilution, you
dilute the bromide to give you lower-contrast, but you also dilute the
developing agent and the alkaline. I think the reason you don't have much
mottling problem is because you are not diluting that much. If you are
developing an 8x10 with 1:4, most probably you will have 200ml stock + 400ml
water in your 8x10 tray. The 200ml stock is enough, so you don't have the
capacity problem that I mentioned in my previous post.
If D-19 has worked for you, I think Dektol will also work (similarly or maybe
even better, depending on what kind of contrast you want). If you are mixing
your own chemical, maybe you can somehow divide the bromide and sulfite so
that with one ratio, you get D-19 and with another ratio, you get Dektol. But
of course, if it ain't broke, why fix it? :)
Or working the opposite way, you can use Dektol as stock but add bromide for
the D-19 effect (increased contrast). This is also mentioned in the new book
which I don't remember the exact title (something like Ansel Adam's Guide to
Photography, book 2).
Dave S.