DIY Effervescent Developer Tablets?

[Alan Johnson]

6NaHCO3,,,,,,,,,,,,+ .....2C6H8O7,,,,,,,,,,,,,,.>..... 2Na3C6H5O7.......+6H20 ..........+6CO2
Sodium Bicarbonate....Citric Acid......................Sodium Citrate .......water.............gas
504...............................384.2..............................516.2,,,,,,,,,,,,,,,,,,,,,108.................264
Requires Sodium bicarbonate to citric acid in ratio 504 to 384.2 or !.31 to 1
Would have to find experimentally how much of this mix is needed to make the compressed developer tablets disintegrate and dissolve.
Might need to adjust slightly to keep the original developer pH

 

[athbr]

6NaHCO3,,,,,,,,,,,,+ .....2C6H8O7,,,,,,,,,,,,,,.>..... 2Na3C6H5O7.......+6H20 ..........+6CO2
Sodium Bicarbonate....Citric Acid......................Sodium Citrate .......water.............gas
504...............................384.2..............................516.2,,,,,,,,,,,,,,,,,,,,,108.................264
Requires Sodium bicarbonate to citric acid in ratio 504 to 384.2 or !.31 to 1
Would have to find experimentally how much of this mix is needed to make the compressed developer tablets disintegrate and dissolve.
Might need to adjust slightly to keep the original developer pH

Hi Alan,

Thanks for doing this legwork.

Just to clarify the numbers on the third row are molar masses?
Also When you say a ratio of 1.31 to 1 you mean the ratio so that all the carbonate and citric acid react?

Yes I agree the best way to figure out how much to use and how much borax to compensate is empirically.

Thanks again.

 

[Alan Johnson]

Yes, they are molar masses, they can be checked on wikipedia if wanted to actually try to make effervescent tablets.
I just did a quick calculation.
Yes 1.31 to 1 is the ratio for the reaction going to completion and all the CO2 removed, it assumes tribasic citrate present at developer pH.

 

[AgX]

Am I correct in understanding these tablets are not actually effervescent?

What action dissolves them then?

As said the efferversence to me is just due to a mistranslation by our fellow member.
There is no hint at such from old-Tetenal.
It would be counterproductive by introducing an unstable ph, by spraying at the moment of insertion and by forming of fine bubbles during processing.
(Tetenal's original use for such tablets was for automated processors, here other prerecquisites are applicable.)

Tetenal considered as well vegetal as synthetic binders plus a synthetic lubricant for making these tablets.
Dissolving takes place due to using an appropriate binder.

 

[AgX]

So far we already got on our field:

-) readymade working solutions for one run (Compard)

-) pouches with concentrates for one run (IlfordPhoto)

-) pouches with dustfree powder (Adox)

 

[athbr]

So far we already got on our field:

-) readymade working solutions for one run (Compard)

-) pouches with concentrates for one run (IlfordPhoto)

-) pouches with dustfree powder (Adox)

Just to give proper context,

I am not in the US or the EU. The only way to purchase these products is internationally and unfortunately it almost always renders itself too expensive once import duties have been accounted for.

That's why I scratch mix and why I'm always looking for ways to make scratch mixing a little bit more efficient.

 

[AgX]

But for someone who mixes his developers himself from scratch it makes no sense at all to press tablets.

I mean, you would have to find out the right auxiliary compounds, find out right particle size, get yourself a tablet press or build such yourself, get a grinder for the components. For what benefit??

 

[athbr]

But for someone who mixes his developers himself from scratch it makes no sense at all to press tablets.

I mean, you would have to find out the right auxiliary compounds, find out right particle size, get yourself a tablet press or build such yourself, get a grinder for the components. For what benefit??

The compounds seem simple enough to acquire. Right particle size seems straightforward with theory and a bit of kitchen counter empiricism. Small tablet presses are easy to acquire, at least in my neck of the woods.

But for what benefit?

1. Less storage requirements
2. Faster setup time
3. To try new things and have fun

Is it doomed to fail? Probably. But that's part of the fun too.