RE: bronzing in pt/pd AND Epson 2400 curves

I see. I hadn't seen you mention the percentage anywhere in your question. I
find that in my studio a 5% solution in a proportion of 6/6/X, that a drop
of 5% is a lot! If I used .7ml (14dr), .7ml(14dr) and 3dr of 2.5% that would
still be a lot for an 8x10 print.

I find that having a contrast agent that is more dilute gives one better
control over the final print. Even after one has gotten good at making negs,
in camera, enlarged, or digitally that fine tuning will still take place to
some degree. And to limit that by having a contrast agent that has too much
effect between 1,2,3 drops is like only using exact times when processing
silver prints or restricting the use of the various contrast grades of
filtration. I can understand large class and limited choices to prevent
confusion.

Why would they need to change their curve? Keep the curve and allow for a
change at the print interpretation.

When I learned printing a few years back, potassium chlorate was the way. As
we made a transition to large prints, 20x24, 30x40 and I made use of burets
to measure solutions. I decided to change the dilution of Pot Chlorate in
the part B to half strength and thus giving me even greater control of the
tonal range and at the same time preventing slight variations from having an
impact on the print. It also prevented our B-ferric with Pot Chlorate, from
going bad as it was used up at a greater rate. Since you are using other
liquids, an additional drop volume will have very little or no impact on the
print while giving you greater control on the contrast range of your print.
This is also why it is a good idea to print at an RH of around 60% as it
eliminates problems in exposure inconsistency and why I include some
platinum in all prints; a blend reacts with less variation to RH.

Eric

Eric Neilsen Photography
4101 Commerce Street
Suite 9
Dallas, TX 75226
http://e.neilsen.home.att.net
http://ericneilsenphotography.com
 
> -----Original Message-----
> From: Christina Z. Anderson [mailto:zphoto@montana.net]
> Sent: Saturday, April 08, 2006 1:22 AM
> To: alt-photo-process-l@usask.ca
> Subject: Re: bronzing in pt/pd AND Epson 2400 curves
>
> I standardized with the students--1 drop of 5% NA2. I could not do the
> percentages with a class that size and with the $$$ I had, much easier to
> do
> one drop of one solution.
>
> They're all constructing their custom curve based on this contrast mix so
> it
> works fine this way. if they changed contrast mixes, they'd have to make
> a
> different curve.
>
> I did 4 13x19 pd prints today with my new pd curve and all worked great!
> No
> bronzing, no nuttin' problem wise. Just a lot scarier coating a pd large
> print than a gum by FAR, and I can also see the benefit of having a large
> magic brush instead of the 1 1/2 inch one I have.
> Chris
>
>
> > Chris, Is that a drop of 20% NA2 for every 6 drops of FO and 6 drops of
> > Palladium? Did you make various batches of Na2 with lowered percentages?
> > Eric Neilsen Photography
Received on Sat Apr 8 10:14:17 2006