Which chemicals, other than surfactants, cause bubbles in film developers? Or which developers have the fewest bubbles?

When I develop film in daylight tanks as one-shots, I always dump them into a large bucket. In the past, I always noticed lots of bubbles there, when I was using developers with sodium sulfite such as d23, d76, etc. I recently changed to a sulfite free developer, Gainers Original MC developer, and now I see absolutely no bubbles in the spent developer at all. So I wonder if it's sulfite causing the bubbles. I would think an antioxidant would reduce bubbles, not increase them, so this is more an academic question. Agitation method of course also has an effect on this.

I am careful to never put surfactants like photoflo or polysorbithane 20 into my tanks or on my reels or channel plates, so this common bubble source is eliminated. I just wonder what experience others have with finding those pesky bubbles in their developers and which chemicals are responsible for them. I still tap the tank a few times after agitation.

I would like to know more about this too as I've also stopped putting wetting agent on my tank and reels and still frequently notice some bubbles right before pouring the developer out.

Alan Johnson said:

Google Search

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Thanks, I tried googling but used wrong terminology?

Yes, sodium sulfite (


) acts as a coalescence-inhibiting salt. It belongs to a group of electrolytes, often including simple inorganic salts, that prevent the coalescence of bubbles in aqueous solutions.

Yes, sodium carbonate (


) acts as a coalescence-inhibiting salt in aqueous solutions, particularly in flotation and bubble dynamics studies, behaving similarly to certain alcohols and other electrolyte solutions to prevent bubbles from merging.

Well, still confused. Both the salt I no longer use, sodium sulfite, and the salt I currently use, sodium carbonate, are coalescence inhibiting salts. Anyway, very noticible lack of bubbles when I dump my developer. I guess maybe one is worse than the other, I know Patrick Gainer was adamant about sulfite free developers, but don't recall anything about low foam, mostly difficulty he had getting it in rural West Virginia.

When I was living in Turkey I initially had an issue with air bells, very hard water, quite a high salt content. I was using Pyrocat HD so almost no Sulphite and a Carbonate level of 0.75% in use.

I noticed that a glass of tap water contained a lot of bubbles, and they just stayed, I experimented with a Paterson tank and reel with just tap water, tapping etc just moved the bubbles. I then added wetting agent, talking drops, and the air bells vanished, it's a fine balance because too much wetting agent will cause foaming.

Now I add Wetting agent when I mix my Developer concentrates, nearly 20 years later no issues.

Ian

Ian Grant said:

When I was living in Turkey I initially had an issue with air bells, very hard water, quite a high salt content. I was using Pyrocat HD so almost no Sulphite and a Carbonate level of 0.75% in use.

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Just the chalk in the water?

Ian Grant said:

I noticed that a glass of tap water contained a lot of bubbles, and they just stayed, I experimented with a Paterson tank and reel with just tap water, tapping etc just moved the bubbles. I then added wetting agent, talking drops, and the air bells vanished, it's a fine balance because too much wetting agent will cause foaming.

Now I add Wetting agent when I mix my Developer concentrates, nearly 20 years later no issues.

Ian

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I always wondered why some people are putting photoflo in their developers! Very interesting, never would have thought of or done that myself. I lived near Yuma AZ on well water a few years ago where the water was 1300 ppm and RO water was around 70ppm, so I used distilled for developer there.

Now, using midwest tap water, which is commercial aquifer well water, water softener and RO filter I have about 5ppm, almost as good as distilled.