How slow did you go??
How slow did you go??
Is it possible to get a film density range which will allow carbon transfer printing?
I believe that Chris is doing that right now.
I made some carbon-transfer prints from my last batch of emulsion, but it was tricky - the density range was too high!
I guess the question about how slow is really saying what's the ultimate quality? The best tonal range and the best grain = ? ASA? Ron maybe you can comment, but my guess is that the magic is in the formula, and therefore is not related to speed?
I too have great admiration for those bromide images of the forties and fifties. They have sometimes that does not exist anywhere else.
Almost ready to start emulsion making!
Addition times from 1' to 15' are possible for this emulsion, but difficult o do by hand. The contrast will be quite low at 15' if everything behaves as normal, and the speed will probably move about 1 stop, but it may appear to slow down due to the loss in contrast. Here is a typical curve of the usual senitometric change with addition times from 8 - 14 minutes with a given emulsion. You can see what happens to speed and density as well as contrast.
A longer addition time would produce a lower contrast, I understand that, but why would it increase speed? Is it because the grains formed first would have more opportunity to grow larger at the expense of the smaller grains than in a more monodisperse emulsion?
You get more speed for the same reason that you get lower contrast. You get a broader size / frequency distribution. There are more fine grains and more coarse grains. With a very fast addition, you get grains that are more nearly alike and they are smaller.
if you go to thelightfarm.com
look under formulas
there is a very simple sea water emulsion
that the maker uses to coat plates
and it only has a few ingredients ..
no crazy chemicals, just silver nitrate
seawater/ salt+water and gelatin ( from what i remember )
salt prints were just saltwater and silver nitrate too, so this is just
a little different ... if a 20year old college student with NO EXPERIENCE
and a booklet from 1904 could do something like his at 2-3am ( in the 1980s )
i think it would be a piece of cake for you ;)
have fun with your experiments!