Effect of reduced Sodium sulfite.

markbau · Mar 30, 2020

So tonight I was mixing up some D76, when it came time to add the sulfite I only had 75g instead of the required 100g, so what I have mixed up is 100% of the metol, hydroquinone and Borax but 75% of the sulfite. Will this be useable or should I chuck it? The 5x7 negs I'll be developing are nothing important, just still lifes taken in the studio.

Rudeofus · Mar 30, 2020

It will likely not make much of a difference, but pH will be lower (Sodium Sulfite is the main alkali in D-76), which could reduce developer activity.

I recommend you use the soup you have plus some easy to get ingredients to mix M-Q Adox Borax developer instead. There will be little difference from 4 vs. 5 g/l HQ. Add 2 g/l Borax and 0.5 g/l Potassium Bromide and you have something very close to M-Q Adox Borax.
@Ian Grant loves that developer, he can probably help you with developer times, if you tell him, which film you use.

markbau · Mar 30, 2020

Rudeofus said:
It will likely not make much of a difference, but pH will be lower (Sodium Sulfite is the main alkali in D-76), which could reduce developer activity.

I recommend you use the soup you have plus some easy to get ingredients to mix M-Q Adox Borax developer instead. There will be little difference from 4 vs. 5 g/l HQ. Add 2 g/l Borax and 0.5 g/l Potassium Bromide and you have something very close to M-Q Adox Borax.
@Ian Grant loves that developer, he can probably help you with developer times, if you tell him, which film you use.

So just add 10% to development time to compensate? I do have bromide which I could add to what I just mixed.

Rudeofus · Mar 30, 2020

I wouldn't know, you are basically charting unknown territory here. Note, that a small drop in pH can mean a large drop in activity, c.f. D-23 vs. D-25. Do you have a pH meter?

Ian Grant can probably help you regarding M-Q Adox Borax developer.

138S · Mar 30, 2020

markbau said:
So tonight I was mixing up some D76, when it came time to add the sulfite I only had 75g instead of the required 100g, so what I have mixed up is 100% of the metol, hydroquinone and Borax but 75% of the sulfite. Will this be useable or should I chuck it? The 5x7 negs I'll be developing are nothing important, just still lifes taken in the studio.

I guess you won't notice much a difference, when using D76 diluted 1:1 you use 50g instead 100g, and development goes from 9min to 12min. In your case developement agents are full strength, so an equivalent development time with 75g probably will be slightly longer, I'd add 30s to 1 min to be in the safe side.

The lower sulfite will also slightly decrease solvent effect, like when diluting D-76.

Effect of reduced Sodium sulfite.

markbau

Rudeofus

markbau

Rudeofus

138S

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