Kodak D76c formula?

Fredrixxon · Sep 14, 2025

D76c Kodak by Ian Grant (lostlabours.co.uk)
Metol 2
Sodium Sulphite 100
Hydroquinone 5
Borax 2
KI 0,01

D76c Kodak by Troop/Anchell (The film developing cookbook)
Metol 2
Hydroquinone 5
Sodium sulfite anhydrous 100
Borax decahydrate 2
Potassium bromide 1
KI 0.04

Which one is the right one? Or none is?

john_s · Sep 14, 2025

FWIW from a long discussion about D76 variants on Ryuji Suzuki's web site, now off line:

"D-76c is a low contrast developer intended for metalographic and spectrographic plates. D-76c contains 0.25g/L potassium bromide and 10mg/L of potassium iodide in addition to straight D-76. One reason for the addition of iodide is said to suppress abrasion marks."

So this is yet another variant.

RalphLambrecht · Sep 15, 2025

john_s said:
FWIW from a long discussion about D76 variants on Ryuji Suzuki's web site, now off line:

"D-76c is a low contrast developer intended for metalographic and spectrographic plates. D-76c contains 0.25g/L potassium bromide and 10mg/L of potassium iodide in addition to straight D-76. One reason for the addition of iodide is said to suppress abrasion marks."

So this is yet another variant.

the one that really works for me is D76h (stable activity over time)

dpurdy · Sep 15, 2025

I have to wonder if you are referring to C-76 which is D76 with an additive called Crone C. Back in the 70s when I was in photo school we students were required to use C-76, which supposedly doubled your ASA and gave finer grain. After finishing the Glen Fishback school of photography I never used it again. I never liked the results but if it was still available I might try it again just to see.

Craig · Sep 16, 2025

john_s said:
"D-76c is a low contrast developer intended for metalographic and spectrographic plates. D-76c contains 0.25g/L potassium bromide and 10mg/L of potassium iodide in addition to straight D-76. One reason for the addition of iodide is said to suppress abrasion marks."

I have a copy of Kodak's "Elementary Photographic Chemistry", copyright date 1941 and it agrees with the above.

D-76c Full formula:
Water 750 ml
Metol 2g
Sodium sulfite anhydrous 100g
Hydroquinone 5g
Borax decahydrate 2g
Potassium Iodide 1% solution 1ml
Potassium bromide 2.5% solution 10 ml
Water to make 1L
Use without dilution.

Dissolve in the order given

Fredrixxon · Sep 16, 2025

Does 1% solution mean 10g in 1000ml of water?

Milpool · Sep 16, 2025

Fredrixxon said:
Does 1% solution mean 10g in 1000ml of water?

Unless otherwise specified that's correct.

john_s · Sep 16, 2025

Craig said:
I have a copy of Kodak's "Elementary Photographic Chemistry", copyright date 1941 and it agrees with the above.

D-76c Full formula:
Water 750 ml
Metol 2g
Sodium sulfite anhydrous 100g
Hydroquinone 5g
Borax decahydrate 2g
Potassium Iodide 1% solution 1ml
Potassium bromide 2.5% solution 10 ml
Water to make 1L
Use without dilution.

Dissolve in the order given

Compared to straight D76, the amount of bromide is pretty ordinary, and I wonder how much effect the iodide would have. I know it's more potent than bromide. Crawley apparently referred, on the topic of FX-1, that the tiny amount of KI made the difference to the acutance, so maybe for scientific purposes the iodide shows up important details. Just a guess.

Kodak D76c formula?

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