Baking Soda Question

ewbank1 · Jun 5, 2018

Pixophrenic said:
If one thinks, optimistically, that by baking you completely converted monohydrate into anhydrous (water-free) sodium carbonate, then all you need to do is to increase the amount of soda in your caffenol recipe by a factor of 1.05. There is no need to bake it every time you need to make a developer.

Yes, now that I have determined the moisture content. It is in a plastic bag and will use the same factor the next time. I was pretty impressed by the results from Caffenol, though my amazement may have just been the fact that it worked at all, rather than that the results were pretty good.

darkroommike · Jun 5, 2018

Pixophrenic said:
The OP apparently also read the label, but the info was not there. The same may apply to more complex mixtures you get at pool supply store. There is no obligation to disclose the components, especially if they are not harmful.

OP said:
"I have a product in the kitchen cupboard labelled - ''Bicarbonate of Soda''.
It's ingrediants are - '' Sodium bicarbonate - 100% ''"
BTW I am a Certified Pool Operator, all pools supplies are carefully labeled, since some combinations can generate chlorine gas or damage skin if improperly handled. The stuff I was referring to is labeled and identified as sodium bromide - 100%

Alan Johnson · Jun 5, 2018

https://pubchem.ncbi.nlm.nih.gov/compound/sodium_carbonate#section=Decomposition
From section 4.2.11, the pH of 5% and !0% anhydrous sodium carbonate at 25C is 11.58 and 11.7 respectively so likely to be similar for samples of a particular brand of washing soda. IIRC washing soda is generally the monohydrate in North America and the tetrahydrate in Europe. Here I am not referring to baking soda or other versions of the bicarbonate,

Pixophrenic · Jun 5, 2018

darkroommike said:
OP said:
"I have a product in the kitchen cupboard labelled - ''Bicarbonate of Soda''.
It's ingrediants are - '' Sodium bicarbonate - 100% ''"
BTW I am a Certified Pool Operator, all pools supplies are carefully labeled, since some combinations can generate chlorine gas or damage skin if improperly handled. The stuff I was referring to is labeled and identified as sodium bromide - 100%

I do not doubt that if the contents are listed at all, this list is correct. But, I just examined the pages of our local pool supply store online, and unfortunately, most of the displayed images do not allow to guess the contents. For example, I was only able to figure out that "pH down" contains sodium bisulfate, but what is 'pH Up" is not indicated on the bottle. Also, more of the bromine tablets on sale are definitely not sodium bromide. I would appreciate the brand and catalog number for that sodium bromide product you mention, so that I could try to ask around.

Pixophrenic · Jun 5, 2018

ewbank1 said:
Yes, now that I have determined the moisture content. It is in a plastic bag and will use the same factor the next time. I was pretty impressed by the results from Caffenol, though my amazement may have just been the fact that it worked at all, rather than that the results were pretty good.

Indeed, especially Caffenol C-L with a little bit of bromide is capable of giving results that are hard to tell from a commercial developer. The problem remains that some films are more prone to fog formation than others, so securing a bromide source is important.

ewbank1 · Jun 5, 2018

Pixophrenic said:
Indeed, especially Caffenol C-L with a little bit of bromide is capable of giving results that are hard to tell from a commercial developer. The problem remains that some films are more prone to fog formation than others, so securing a bromide source is important.

I used the Caffenol C-H formula using sodium bromide. The results compared very favorably to the roll I had done previously with XTOL. Maybe a bit more grain and a bit of fog.

Pixophrenic · Jun 6, 2018

Alan Johnson said:
https://pubchem.ncbi.nlm.nih.gov/compound/sodium_carbonate#section=Decomposition
From section 4.2.11, the pH of 5% and !0% anhydrous sodium carbonate at 25C is 11.58 and 11.7 respectively so likely to be similar for samples of a particular brand of washing soda. IIRC washing soda is generally the monohydrate in North America and the tetrahydrate in Europe. Here I am not referring to baking soda or other versions of the bicarbonate,

Thank you Alan. This answer should be put in the resource section, as more converts will be wondering about household grade washing soda. However, I still stand by my suggestion that assuming that household grade washing soda is not anhydrous, and one needs 2.66 times more decahydrate than anhydrous, the easiest way is to test your batch with indicated amount and with twice as much.

wahiba · Jul 26, 2022

All caffenol ingredients are available raw from Amazon. Even coffee although it is easier to buy cheap stuff while shopping. Washing soda can often be found in super markets. Vitamin C powder in super markets, check in baking section rather than health section, is not often available and crushing tablets is a bit hit and miss.

Baking Soda Question

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