Hello! Thank you all for the amazing resources on alternative processes.
I'm finding a working emulsion formula and getting the technique down.
- My math is to coat two 22x30 sheets of Arches 90lb hot press (I'll post the formula first and go into my math below)
- Like most people, I'd like deep blacks and smooth transitions in the highlights.
- I hope this will give me something around 10iso and grade II paper
- My gut tells me the silver content is a little low, but it matches the numbers PE had mentioned about AgNO3 density
Would love thoughts and feedback!
Bromo-Iodide Silver Gelatin Paper Enlarging Emulsion (110 ml)
12% silver solution
1.8 g AgNO3
13.2 ml Water
1st Melt (15% total gelatin)
1.35 g Gelatin (food grade pure bovine hide)
42 ml Water
4.75 g KBr (5% in total gelatin solution)
.2 g KI (0.2% in total gelatin solution)
2nd Melt (85% total gelatin)
7.65 g Gelatin
39 ml Water
Working temperature is 130 F
Add silver solution, drop by drop to 1st melt over 5 minutes
Hold for 5 minutes
Add 2nd melt
Hold for 30 minutes
Chill and Noodle
Wash until no salt precipitates (check by adding drops of silver solution to the spent wash)
Drain and wring out THOUOUGHLY
Finals - 2 ml Everclear (I will be using the emulsion within a week)
Math and Technique
This is a sort of hybrid from much of what I've read here
I'm sourcing the numbers from PE's archive, Denise's book, and an old Eastman recipe that's floating around
I understand this is an art as well as a science, and am more or less trying to get a handle on the process and nature of things (being precise for the sake of repetition and process, rather than the sake of precision and competition)
Silver Content (15 ml)
I see that emulsion can be coated at 12ml / square foot
I see that AgNO3 can be 200mg / square foot
- Therefore coating two 22x30 papers (apx. 9.2 square feet) will use 110ml of emulsion
- Therefore I will need 1.84 g AgNO3 for the total coating
- A 12% solution from this yields the 13.2ml water
Salted Gelatin (95 ml)
The remaining 95 ml of solution will be 10% gelatin accounting for the salt content
The Eastman recipe uses 5% KBr and 0.2% KI with respect to the total salted gelatin solution
- Therefore the 4.75 g KBr and 0.19 g KI
- 95ml solution - 4.95 g salts = 90 ml of working 10% gelatin solution remaining (9g gelatin and 81ml water)
The Eastman recipe splits the first melt 15% of the total gelatin in 52% of the total water
- Therefore the first melt has 1.35g gelatin and 42ml water
- Therefore the second melt has the remaining 7.65 g gelatin and 39 ml water
Process
I've seen mixed things about temperature and silver addition times, and ripening.
I don't mind a bit of a coarser grain right now, I'm more concerned about contrast, speed, and dmax
- Adding silver over 5 minutes should give a coarser grain, and stronger contrast
- 30 minutes of ripening at 130F feels like a good middle ground from the many mixed reviews lol
Coating
I plan to coat papers immediately after adding the finals at 95 F
I cannot afford a wire round coating rod ATM, and will be using a 16 thread/inch threaded stainless steel rod from home depot
Coating 5x7 pages of arches 90 lb hot press with 3ml of emulsion for contact printing and enlarging
Coating on a level piece of old window glass from the restore
Will eventually coat larger 22x30 sheets with 55ml of emulsion
Feel free to correct any mistakes, do not want to spread bad info.
Much love!
I'm finding a working emulsion formula and getting the technique down.
- My math is to coat two 22x30 sheets of Arches 90lb hot press (I'll post the formula first and go into my math below)
- Like most people, I'd like deep blacks and smooth transitions in the highlights.
- I hope this will give me something around 10iso and grade II paper
- My gut tells me the silver content is a little low, but it matches the numbers PE had mentioned about AgNO3 density
Would love thoughts and feedback!
Bromo-Iodide Silver Gelatin Paper Enlarging Emulsion (110 ml)
12% silver solution
1.8 g AgNO3
13.2 ml Water
1st Melt (15% total gelatin)
1.35 g Gelatin (food grade pure bovine hide)
42 ml Water
4.75 g KBr (5% in total gelatin solution)
.2 g KI (0.2% in total gelatin solution)
2nd Melt (85% total gelatin)
7.65 g Gelatin
39 ml Water
Working temperature is 130 F
Add silver solution, drop by drop to 1st melt over 5 minutes
Hold for 5 minutes
Add 2nd melt
Hold for 30 minutes
Chill and Noodle
Wash until no salt precipitates (check by adding drops of silver solution to the spent wash)
Drain and wring out THOUOUGHLY
Finals - 2 ml Everclear (I will be using the emulsion within a week)
Math and Technique
This is a sort of hybrid from much of what I've read here
I'm sourcing the numbers from PE's archive, Denise's book, and an old Eastman recipe that's floating around
I understand this is an art as well as a science, and am more or less trying to get a handle on the process and nature of things (being precise for the sake of repetition and process, rather than the sake of precision and competition)
Silver Content (15 ml)
I see that emulsion can be coated at 12ml / square foot
I see that AgNO3 can be 200mg / square foot
- Therefore coating two 22x30 papers (apx. 9.2 square feet) will use 110ml of emulsion
- Therefore I will need 1.84 g AgNO3 for the total coating
- A 12% solution from this yields the 13.2ml water
Salted Gelatin (95 ml)
The remaining 95 ml of solution will be 10% gelatin accounting for the salt content
The Eastman recipe uses 5% KBr and 0.2% KI with respect to the total salted gelatin solution
- Therefore the 4.75 g KBr and 0.19 g KI
- 95ml solution - 4.95 g salts = 90 ml of working 10% gelatin solution remaining (9g gelatin and 81ml water)
The Eastman recipe splits the first melt 15% of the total gelatin in 52% of the total water
- Therefore the first melt has 1.35g gelatin and 42ml water
- Therefore the second melt has the remaining 7.65 g gelatin and 39 ml water
Process
I've seen mixed things about temperature and silver addition times, and ripening.
I don't mind a bit of a coarser grain right now, I'm more concerned about contrast, speed, and dmax
- Adding silver over 5 minutes should give a coarser grain, and stronger contrast
- 30 minutes of ripening at 130F feels like a good middle ground from the many mixed reviews lol
Coating
I plan to coat papers immediately after adding the finals at 95 F
I cannot afford a wire round coating rod ATM, and will be using a 16 thread/inch threaded stainless steel rod from home depot
Coating 5x7 pages of arches 90 lb hot press with 3ml of emulsion for contact printing and enlarging
Coating on a level piece of old window glass from the restore
Will eventually coat larger 22x30 sheets with 55ml of emulsion
Feel free to correct any mistakes, do not want to spread bad info.
Much love!
Last edited:
