Sodium Carbonate from the grocery

[Mateo]

I unexpectedly ran out of Sodium Carbonate and want to use Arm and Hammer washing soda. For paper developers I just assume that it's crystal and convert 100 grams crystal = 43 grams monohydrate and then I adjust the carbonate like crazy anyways. Now I need it for film and want to keep the activity at what I'm used to. Do I need to make a saturated solution and start from there to know precisely how much carbonate I have and if so how many grams per liter are in a saturate solution of sodium carbonate? Or can I just use the conversion because it will be close enough? I hope one of you chemistry types can help.

 

[MikeK]

Arm & Hammer the monohydrated form of Sodium Carbonate. I have only used it formulating paper developers, but you should multiply by 2.33

Check out this link for a bunch more chamical conversions

http://www.jackspcs.com/chemconv.htm

Have fun

Mike

 

[gainer]

I hope I am not repeating. I hit the wrong button.

Mike,
You got the ratio right for washing soda to monohydrate, but washing soda is the decahydrate. Washing soda to anhydrous is 2.7. monohydrate to anhydrous is 1.17

Pat Gainer

 

[MikeK]

Pat:

Thanks for the clarification. I originally gleaned this information from an email on another forum that was sent by an guy from Arm & Hammer and I believed what was posted.

Interestingly though, I have formulated many print developers using washing soda with obviously the wrong weights but with great results. I might have had a different experience if I was making film developers.

Mike

 

[Mateo]

Hey thanks guys,

you confirmed that the numbers I was using were good. I had two exposures that were the same and I reveal one negative at a time so I tried the washing soda no problem.

 

[dancqu]

Pat:

...a guy from Arm & Hammer and I believed what was posted.
...I have formulated many print developers using washing soda with obviously the wrong weights...

Not so. Mr. Gainer has seconded your 2.33 multiplier. He has only
pointed out that it is a deca not the mono as you mentioned. You
owe A&H an apology. Dan

 

[MikeK]

oooh the confusion. The email thread that included the quote from Arm and Hammer said that A&H Sodium Carbonate was of the mono type..

but never mind all is clear now, I hope. And more importantly the measures I use for my cold tone and warm tone developers work for me

Yours thoroughly carbonated

Mr. Fizz - Mike