Sodium Bicarbonate - 2g
Ascorbic Acid - 4g
Water to make 200mL (wait for bubbles to clear)
Acetaminophen - 15g (dissolve in ascorbate solution - heat if necessary)
Once the acetaminophen is dissolved there will still be the binder and other "stuff" floating around. You can filter this through a paper towel before adding the hydroxide to avoid getting any on your fillm.
Sodium Hydroxide - 8g (use 80mL of 10% solution to avoid heat)
Let this stand for 72 hours in a sealed container.
Borax saturate solution - 400mL
Ascorbic Acid - 6g
Tylenol solution
Water to make 1L
This first portion is what we'll call TCB Part A. It is too active to use as-is so we must dilute it but not in the traditional sense with water. We will dilute with a borax/ascorbate mixture which we'll call TCB Part B as follows:
Borax saturate solution - 400mL
Ascorbic Acid - 6g
Water to make 1L
This will keep the levels of borax and ascorbate up while using smaller amounts of p-aminophenol. Use parts A:B 1:2 for a normal developer (7 mins) and 1:3 for stand development.
Here is a sample:
This is Tri-X @ EI 400 in TCB for 7:00 @ 19C. Grain looks good and it could use a bit longer development time. It requires further testing but the results so far are promising. The other potential complexity is sodium hydroxide as it may be difficult to find for some. I get it from the local hardware store (a.k.a. Lye and Caustic Soda) and it's available from soap making suppliers. Erik alluded to not having to use Sodium Hydroxide but I'm not much of a chemist and that's beyond me.
MM
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I would love you to explain a little more here MM!
ReplyDeleteThe first part of the recipe seems a little complicated. Why Sodium bicarbonate? You don't mean Disodium carbonate by any chance? I'd guess if that was the case that you could loose both that and Lye for about 25 gram of Na2CO3, washing soda....
Du you have access to pure Acetaminophen?
Then finally why add more ascorbic acid in the second stage, why not put it in in the first?
Just interested and curious, since my head spins from many chemicals in one soulution....
:-)
I'll be the first to admit that this recipe may be more complicated than necessary and there is most likely room for improvement and simplification.
ReplyDeleteThe rationale for using sodium bicarbonate is simply a quick way of converting ascorbic acid to ascorbate with a near neutral pH. I could have done it with sodium hydroxide which would make ascorbate in a high pH solution but the problem I found is that the Tylenol tablets do not dissolve easily at high pH. I wanted ascorbate in the water before dissolving the Tylenol to prevent oxidation and have the solution near neutral pH to expedite mixing.
I don't have access to pure acetaminophen but p-aminophenol is available through chemical suppliers and would eliminate the need for the acetaminophen to p-aminophenol conversion. I use 500mg acetaminophen/paracetamol tablets ... nothing special.
I add the ascorbic acid later for two reasons. The first is that if I added it first I would need more sodium carbonate and have more effervescence to deal with. The second is that I already have stock solutions with the correct proportions of borax and ascorbic acid to save time. This is a long way of saying I'm lazy ;-) Once I'm comfortable that the recipe is good and stable I will look at simplifying it but for the time being, this fits my current work-flow best.
OK Sodium bicarbonate can be found in the bakery section, baking soda. Purrrfect! The fizzing is living proof something *happens*.
ReplyDeleteYou can - if you wish replace 8 g NaOH with ca 22 g of Na2CO3... It will give the same with less pH, a littleless activity & longer dev. times?
Since you use tablets like mine : I found I need to seperate the gunge that makes tablets out of the medicine, mainly binder and heavy sugars. I gather this mix of yours filters through a coffe filter? Since NaOH is very thick & slippery Na2CO3 would probably be better if that is an option....
Looking fdorward to further work here, this is perfect, can't wait for the next instalment. In the meantime I'll continue my big chemistry lesson!
Re the tylenol tablets, the binder is there but I didn't bother filtering it for this test. A simple paper towel or coffee filter should work fine. I will test that next time around.
ReplyDeleteActually from what I remember when I dabbled with this, my coffefilter got clogged, a paper towel worked best the second time around.
ReplyDeleteThe gunge is quite sticky and the basic substances don't help at all.