Metol in tap water...pink???

BradS · May 1, 2018

I mixed up a batch of D-23 using tap water last weekend. This is the first time I've ever mixed with ordinary tap water. When the Metol was added to the water, the water immediately turned pink....of course, the solution cleared shortly after adding Sodium Sulfite.

My question, what can I expect from this batch of D-23 ? Is the color a indicator of some benign nuisance chemical (the water is very hard) ? or did I just waste 5g of Metol and 100g of sulfite ?

Saganich · May 1, 2018

Perhaps oxidation was occurring prior to adding SS. Do you add a pinch of SS before the Metol? I would say no worries.

DREW WILEY · May 1, 2018

Are you still living near Sonora? If so, the water is probably hard enough to need a jackhammer. Used distilled for developer and final rinse. But the previous post identifies the pinkness issue. You need a tiny bit of sodium sulfite dissoved in the water in order to get the metol itself to dissolve. Apparently it acts like a wetting agent. But don't use much or it won't dissolve at all. A "pinch" is an appropriate expression. Water hardness might also be a factor due to the calcium or other sources of alkalinity. Maybe tanins are present too. Are you on city water or well water?

BradS · May 1, 2018

I have city water and sewer in Sonora - fantastic water (but breathtakingly expensive!)
I have been working a long-term contract in the bay area so, this is Pleasanton city water...definitely hard enough to drive tent stakes!

jim appleyard · May 1, 2018

This is normal for me. I always get a pink metal/tap water solution and like you, it clears up with sulfite. Your D-23 should work just fine. Mine does.

BradS · May 1, 2018

jim appleyard said:
This is normal for me. I always get a pink metal/tap water solution and like you, it clears up with sulfite. Your D-23 should work just fine. Mine does.

Ah...good. Thanks.

Sirius Glass · May 1, 2018

XTOL Solution A turns the water pink until Solution B is added. It could be normal for D-23.

glbeas · May 1, 2018

I was reading up on some old developer formulas and a pinch of sulfite is required just before the metol to prevent the metol from oxidizing while it is being mixed. Any more and the metol will not dissolve. Finicky stuff!

RPC · May 1, 2018

glbeas said:
I was reading up on some old developer formulas and a pinch of sulfite is required just before the metol to prevent the metol from oxidizing while it is being mixed. Any more and the metol will not dissolve. Finicky stuff!

That is what I have read as well. I don't believe the pinch is necessary to allow the metol to dissolve as some believe.

When I mix developers from scratch I always used distilled water just to be safe.

Arklatexian · May 1, 2018

glbeas said:
I was reading up on some old developer formulas and a pinch of sulfite is required just before the metol to prevent the metol from oxidizing while it is being mixed. Any more and the metol will not dissolve. Finicky stuff!

Because, I too, have read that and I do it when mixing Beutler's, even in distilled water. Certainly works better than this blasted spell checker on my computer.........;.;.Regards!

Gerald C Koch · May 2, 2018

The amount of oxidation is insignificant.

BradS · May 7, 2018

Gerald C Koch said:
The amount of oxidation is insignificant.

Thank you Gerald.

I developed a roll of Tri-X last night and it came out quite nice.

RPC · May 7, 2018

Gerald C Koch said:
The amount of oxidation is insignificant.

So is there any good reason for the pinch of sulfite?

Ian Grant · May 7, 2018

RPC said:
So is there any good reason for the pinch of sulfite?

Yes to stop the slight oxidation if it gives you piece of mind

Ian

Rudeofus · May 8, 2018

If Metol is oxidized, there are a few things which can happen:

it is reduced back to its original state by a stronger reducer like Ascorbic Acid, HQ, Glycin, ... - this is the typical reaction in super additive developers
it reacts with sulfite ion and is converted to a colorless sulfonate - this is the typical reaction in Metol only developers like Microdol or D-23/25/76H/...
it reacts with itself and forms some variation of humic acid - this is the colorful reaction product you saw when you mixed Metol in tap water. Chances are your tap water is slightly alkaline, which accelerates the reactions vs. deionized water.

These three possible reaction do not run at the same speed, the higher up reactions are typically an order of magnitude faster than the lower ones. Since you only had Metol and water, you were able to observe reaction type 3. As others have already said: no harm done, little Metol was lost (too little to matter) and later converted to sulfonate by the added sulfite.

BradS · May 8, 2018

Rudeofus said:
If Metol is oxidized, there are a few things which can happen:

it is reduced back to its original state by a stronger reducer like Ascorbic Acid, HQ, Glycin, ... - this is the typical reaction in super additive developers

it reacts with sulfite ion and is converted to a colorless sulfonate - this is the typical reaction in Metol only developers like Microdol or D-23/25/76H/...

it reacts with itself and forms some variation of humic acid - this is the colorful reaction product you saw when you mixed Metol in tap water. Chances are your tap water is slightly alkaline, which accelerates the reactions vs. deionized water.

These three possible reaction do not run at the same speed, the higher up reactions are typically an order of magnitude faster than the lower ones. Since you only had Metol and water, you were able to observe reaction type 3. As others have already said: no harm done, little Metol was lost (too little to matter) and later converted to sulfonate by the added sulfite.

Very interesting. Thank you.

Metol in tap water...pink???

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