Re: Gum Bichromate Kit from Photo. Formulary
Albert Strauss (a.strauss@worldnet.att.net)
Sat, 20 Jul 1996 22:05:17 GMT
At 04:08 AM 7/20/96 +0000, Judy Seigal wrote:
>
>On Sat, 20 Jul 1996 Gumprint@aol.com wrote:
>> Perhaps you are after a single emulsion. I have been
>> making gums since 1978 and have not made a successful single emulsion yet.
>
>As for paper, I'm always chasing the magic paper (not yet found), and have
>some I prefer to BFK for their smoothness -- but none is as generally
>safe, clean, loyal, obedient and hardworking as BFK. However, it stains
>with some combinations of size and color. I did a series of tests this
>spring with the different gelatines & BFK was not good. (And did I mention
>that the more gelatine the more staining in many cases?)
>
Yes strange ain't the word fot it. For single coat I have found that
presoaked BFK (which one assumes has washed out the surface size) stains
less for me then a single layer of hardened gelatin sizing. Go figure--
I think they change the rules each month and soon the gelatin size will
probably work better. By the way - My experiments using unpigmented
gum w/bichromate as a size (on BFK) have not been successful. After
exposure, the gum changes to a beige color which won't wash out. This
results in the
subsequent pigmented layers having dingy highlights. Also the pigmented
layers seem to have a greater tendency to slide off the paper during
development.
>I know you still don't believe me. OK, for one-coat gum try: Rowney
>gouache jet black as pigment, and equal parts water, heavy gum, and
>saturated ammonium dichromate for the rest of the mix... good one-coat
>gums, honest, on all kinds of fresh (never wet) paper from Plover bond (or
>other rag content typing paper) to Strathmore bristol drawing to BFK.
>
Per your suggestion I tried the gouache on virgin BFK. It worked very well.
I did not add water since the gum I used was rather thin. In fact the image
was sharper then I usually get. I could actually see the dots from my half tone
negative. This would not be unusual for platinum but it is for gum.
Al