Peter Schrager
Subscriber
The 2x brush coated print seems contrastier and more neutral in tone. Do you know why?
Very nice!
Can you get smooth tones with brush coating? Or is rod coating always better in that respect?
The 2x brush coated print seems contrastier and more neutral in tone. Do you know why?
Any other questions please inquire!
A) ammonium chloride .8gSome formulas as you use them would be great to hear about!
A) ammonium chloride .8g
gelatin 24g 250 bloom
Dh2o 200ml
in a 500ml beaker dissolve the ammonium then add the gelatin
let sit for 25 minutes
B) tartaric acid .8g
NaBiCarbonate .4g
Potash Alum .5g
Dh2o 30ml
C) Silver nitrate 10g
citric acid 6g
Dh2o 50ml
split the silver and the C.A into 2 separate vials 25ml each and combine right before adding to the above.
heat gelatin. mix to 122 degrees F.
Heat B to same temp and add to A
C heated to 122 degrees F. to the above in a slow steady stream during one minute
preferably you are using a hotplate/stirrer as it makes life simple
stir the above at 550 RPM for 15 m minutes
Finals added:
20 ml grain alcohol
20 drops foto-flo
20 ml glyoxol 4%
5ml thymol 2%
I like to let the emulsion digest for up to one hour at 122 degrees F
this will prevent little stars from forming on the paper.
I coat the paper 2x as I have not found the magic ingredient that will give me the contrast I like with coating once.
At times I have added CaCr207; cobalt ; and cadmium with varying degrees of success (one only!)
you can use a brush or a rod to coat....
I also tape the paper to a slightly oversized piece of glass for coating; then place on a rack to let harden
do not wait too long to remove as the paper will stick to the glass!!
using hangers with clips to let dry
These are some of the variables you can instill while creating your own emuldion. Rod coating will always be sharper than brush but one can use these variables to your advantage.
we coat A - B // then C ---- OR
add A to B and C all in one Then coat the paper ????
please reread what I wrote ...emulsion gets made first; digest for one hour then coatwe coat A - B // then C ---- OR
add A to B and C all in one Then coat the paper ????
Hi All,
I'd like to submit my work on P.O.P. to the conversation. Hopefully, it's either of interest or help to the emulsion newbies among us.
d
Unfortunately, I developed a severe sensitivity to bichromate and had to quit.
You're probably amply aware of the fact that various pigment processes have arisen that can act as a substitute for gum bichromate. They usually involve a much more sensible sensitizer like ferric ammonium citrate (there's a recent thread here on Photrio that uses fish gelatin as a colloid). There's of course also Zerochrome SBq and Calvin Grier's Printmaker's Friend that exploit more contemporary sensitizer/photopolymer systems.
Hi Bob. I think hand-coated silver is about to get its time in the spotlight. The creative potential with a medium that was standard for a hundred years has a lot of material to work with. Gum over silver gelatin was one that missed out because people started using commercial paper almost immediately. The hard supercoating on commercial paper doesn't work well with gum coatings. Handmade paper solves that. When I developed the "silvergum" process, I thought that would be my art form for the rest of my creative life. I think it's gorgeous. Unfortunately, I developed a severe sensitivity to bichromate and had to quit. That was a painful day. But bless art, there is always a new path to discover. Today, my heart belongs to handmade paper negatives. You and your students might consider a paper negative to handmade paper workflow. I think paper negatives (by way, perhaps, of a digital internegative) with POP could be marvelous.
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