Will the real Mytol please stand up

albada

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I've discovered three formula's for Paul Lewis' Mytol developer (a clone of XTOL). They are:

Formula #1: Published in The Darkroom Cookbook:
Water ..................................... 750 ml
Sodium sulfite (anhydrous) ....... 85 g
Sodium metaborate 4H2O ........ 4 g
Sodium ascorbate ................... 12 g
Phenidone .............................. 0.15 g
Sodium metabisulfite .............. 3 g
Water to 1 L

​

Formula #2: Published in The Film Developing Cookbook:
Water ..................................... 750 ml
Sodium sulfite (anhydrous) ....... 60 g
Sodium metaborate 4H2O ........ 4 g
Sodium ascorbate ................... 12 g
Phenidone .............................. 0.15 g
Sodium metabisulfite ............... 3 g
Water to 1 L

​
Formula #3: From an apug.org posting:
Water ..................................... 750 ml
Sodium sulfite (anhydrous) ....... 60 g
Sodium metaborate 4H2O ........ 4 g
Sodium ascorbate ................... 13 g
Phenidone .............................. 0.15 g
Sodium metabisulfite ............... 3 g
Water to 1 L

​
Any idea which one is correct?
For comparison, here's a formula for XTOL which I took from the XTOL-patent which I downloaded:

Sodium sulfite ........................ 85 g
DTPA .................................... 1 g (omitted in Mytol)
Sodium metaborate (8 mol) ..... 4 g
Sodium isoascorbate ............. 12 g
Dimezone S .......................... 0.2 g (Phenidone = 0.15 in Mytol due to higher activity?)
Sodium metabisulfite ............. 3.5 g (= 3.0 in Mytol)

​
I'm tempted to say that formula #1 is correct because its sulfite agrees with XTOL (85g), but I wonder if the lower Sodium metabisulfite in it will cause the pH to be too high. Unless that compensates for the omission of DTPA (is DTPA a base?).

Formulas #1 and #2 differ in sulfite, but I see no change in anything else to adjust pH, making me think one of these must be wrong. Grrr...
 
OP
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albada

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Yes, you do remember correctly, and I should have mentioned that note in my posting. Sulfite is an alkali, and changing it will change pH. But I see no other change to compensate for that pH-change, making me think the 85g version will be too alkaline (pH too high). Unless, as you said, the change is too small to matter.
 

Gerald C Koch

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I wish that I could do a New York accent here -- "Don't worry about it!" The differences in the 4 formulas are not enough to be of concern. Pick one and use it. The last time I looked the definition of photography was the art of taking pictures not obsessing about this developer or that developer.

Kodak uses the isoascorbate because it is cheaper and slightly more active. The molecular weights of the developing agents Phenidone, Dimazone S, etc are all slightly different as are their activities. Small difference are possible because of this.
 
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paul ron

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FaGedAboudIt! Dare ya go.. Oh Aeah E I O U.... sump times WHY?

Why not test all of em, couple a two tree o four, n help everyone here learn sumptin? OOOOooo! :confused:
 

Gerald C Koch

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paul ron said:
FaGedAboudIt!
Click to expand...

This is exactly what I had in mind. I could hear it in my head but didn't know how to transcribe it. Thanks!

Jerry
 
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Gerald C Koch

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The change in pH between 60 and 85 g/l of sulfite is not going to be very much. As I said previously you are not going to see much difference in activity among the four formulas.
 
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albada

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Gerald C Koch said:
The change in pH between 60 and 85 g/l of sulfite is not going to be very much. As I said previously you are not going to see much difference in activity among the four formulas.
Click to expand...

I got the point, and I was culturally enriched in the process!

Mark Overton
 

Alain Deloc

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Hi there,

Did anyone tried to replenish Mytol with fresh working solution in the same way Xtol can be replenished with 70ml of fresh working solution?
 

Alain Deloc

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{Moderator note: starting with this one, a couple of posts were moved from a thread on FX37 because they fit better in the present thread. The original discussion including @retina_restoration's quoted post below appears here: https://www.photrio.com/forum/threa...oper-for-t-max-delta-films.23457/post-2764326 }

retina_restoration said:
(You don't mention whether you have a specific film in mind or not)
Click to expand...

I am shooting Double-X (I have a reel) and HP5 pushed. I wonder if Mytol can be self-replenished as Xtol, with 70ml (or other value) of fresh working solution.
 
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Don_ih

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Alain Deloc said:
I wonder if Mytol can be self-replenished as Xtol, with 70ml (or other value) of fresh working solution.
Click to expand...

I use the instant variety of Mytol and I don't know that I'd want to push my luck trying any replenishment regime or even keeping any stock of the stuff around. Other who have tried it should chime in. But it's reasonable enough to just mix it as you need it and use once.
 

Lachlan Young

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Alain Deloc said:
I am shooting Double-X (I have a reel) and HP5 pushed. I wonder if Mytol can be self-replenished as Xtol, with 70ml (or other value) of fresh working solution.
Click to expand...

You will be better off buying some Adox XT-3, unless you are prepared to buy DTPA and make up your own Xtol from the Kodak patent. If you want to run a replenished system and are not aware of the potential issues with the Fenton reaction in non/ poorly sequestrated Ascorbate developers, you are setting yourself up for sudden failure.
 

Alain Deloc

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I have some DTPA that I used to mix Ron Mowrey's (PE) C41 formula.The only thing I don't have is ascorbate.
 
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Alain Deloc

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I found this post https://www.photrio.com/forum/threads/will-the-real-mytol-please-stand-up.84293/ and I was thinking to mix the last formula, the one that's supposed to be the XTOL-patent

Sodium sulfite .............................. 85 g
DTPA ....................................................1 g (omitted in Mytol)
Sodium metaborate (8 mol) ..... 4 g
Sodium isoascorbate ................ 12 g
Dimezone S ................................. 0.2 g (Phenidone = 0.15 in Mytol due to higher activity?)
Sodium metabisulfite .............. 3.5 g (= 3.0 in Mytol)

I have all the ingredients except ascorbate. Not sure what the (8 mol) means but I believe it's octahydrate, and since I don't have metaborate I played a bit with chemical equations and it seems that 7g Na2B407.10H20 (borax) +1.5g NaOH = 10g Sodium metaborate (8 mol). I rewrote the above formula with substitutions as follows:

Water ............................................. 750 ml
Sodium sulfite ................................. 85 g
DTPA ...................................................... 1 g
Borax .................................................. 2.8 g
Sodium Hydroxide ....................... 0.6 g
Sodium isoascorbate ....................12 g
Dimezone S .................................... 0.2 g
Sodium metabisulfite ................. 3.5 g
Water to 1 L

But I am not sure if this formula can be trusted. Is this really the Xtol?
 
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Alan Johnson

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Metaborate - Silvergrain Research

web.archive.org
Yes it is really Xtol as example1 in US Pat 5756271 [FDC 2020 p61], your calculation is correct.
Instead of 12g isoascorbate one may use 10.67g ascorbic acid plus a further 2.42g sodium hydroxide.
I have made up this and used it without the DTPA ,pH was 8.3. It was in a glass bottle under inert gas.
I never pursued it [2015] as it is cheaper to buy a packet of Xtol, or today, the Adox version.
 

Alain Deloc

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While you were typing your answer I was doing the calculus for sodium ascorbate substitution , hahaha ) I got this formula and it matches your values. But I got a slightly different value for Ascorbic acid
HC6H7O6 (ascorbic acid) + NaOH(sodium hydroxide) → C6H7NaO6 (sodium ascorbate) + H2O
176.12 gr. ascorbic acid + 40 gr sodium hydroxide-> 198.10 gr sodium ascorbate + 18 gr. water
0.88 gr ascorbic acid + 0.2 gr NaOH -> 1 gr sodium ascorbate + 0.09 gr. water
10.56 gr ascorbic acid + 2.4 gr NaOH -> 12 gr sodium ascorbate + 1.08 gr. water

Water ........................................................... 750 ml
Sodium sulfite ............................................. 85 g
DTPA ................................................................... 1 g
Borax ............................................................... 2.8 g
Sodium Hydroxide ........................................ 3 g
Acorbic acid ............................................ 10.56 g
Dimezone S ................................................. 0.2 g
Sodium metabisulfite .............................. 3.5 g
Water to 1 L

And because it was fun to make some substitutions, I replace sodium metabisulfite with sodium sulfite and negative value NaOH like following :
1gr sodium metabisulfite = 1.33 gr sodium sulfite - 0.41gr sodium hydroxide + 0.09gr water
3.5gr sodium metabisulfite = 4.65 gr sodium sulfite - 1.43gr sodium hydroxide + 0.315gr water
With this substitution, I got this Xtol formula

Water ........................................ 750 ml
Sodium sulfite ..................... 89.65 g
DTPA ................................................. 1 g
Borax ............................................. 2.8 g
Sodium Hydroxide ................ 1.57 g
Acorbic acid .......................... 10.56 g
Dimezone S ................................ 0.2 g
Water to 1 L

And because I don't have DTPA as free acid, but as DTPA-Na5 sol. 40% (got it from Fototechnik), I made a new chemical reaction:
5*NaOH + DTPA = Na5-DTPA + 5*H2O
200g NaOH + 393.34g DTPA = 503.25g Na5-DTPA + 90g H2O
1 gr DTPA = 1.28 g Na5-DTPA - 0.51 gr NaOH + 0.22 gr. H20
1 gr DTPA = 3.2 gr Na5-DTPA sol. 40% - 0.51 gr NaOH + 0.22 gr. H20
With this last molar substitution which requires also a decrease of NaOH, I got this equivalent Xtol formula

XTOL formula (with molar substitutions)
Water ........................................ 750 ml
Sodium sulfite ...................... 89.65 g
DTPA-Na5 sol. 40%................ 3.22 g
Borax.............................................. 2.8 g
Sodium Hydroxide..................1.06 g
Acorbic acid .......................... 10.67 g
Dimezone S ................................ 0.2 g
Water to 1 L.

Edit : I modified the above formula according to @Alan Johnson recommendation.
 
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Alan Johnson

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Instead of 12g isoascorbate one may use 10.67g ascorbic acid plus a further 2.42g sodium hydroxide.
This is right, your figure of 0.88g AA should be 0.889 and caused a slight error.
I have not checked the DTPA calculation or that for metabisulfite.
It might be better to have a new thread if you wish to present an Xtol formula.
 
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Alain Deloc

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koraks said:
Why reinvent the wheel? There are several formulas of mytol and 'instant mytol' online that already solve these issues.
Click to expand...

I rewrote that Xtol formula for myself last night. I never knew about it until yesterday when I found it accidentally browsing Photrio. I think mixing Xtol instead of Mytol or Instant Mytol has some advantages because of stability in time. Mixing takes time and focus, and making 500 ml of Instant Mytol in order to develop 2 films and then throw it away is a turnover (for me).

But that Xtol formula uses DTPA, which prevents Fenton reaction (sudden death), so it caught my attention. DTPA as free acid is hard to find, I was able to get only DTPA-Na5 salt as a 40% solution, which is very easy to handle but it requires some molar substitutions in the formula in order to use it. Also I substituted Sodium Metaborate with Borax and Sodium hydroxide because these chemicals are much more available everywhere and they are very cheap also. In the end, I noticed that Metabisulfite could be substituted with Sodium Sulfite and a reduction of the NaOH total amount. I did that in order to keep the formula as short as possible and also as cheap as possible.
 
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Alain Deloc

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Damn! You're right! I will redo the math.
 

dokko

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Alain Deloc said:
Also I substituted Sodium Metaborate with Borax and Sodium hydroxide because these chemicals are much more available everywhere and they are very cheap also.
Click to expand...
that might be a good plan if you're a fully trained chemist and have access to a well equipped chemical lab, but personally I'll gladly pay 50 bucks more not have to handle Sodium hydroxide again, which is easily one of the nastiest chemicals I handled in my life.
 

koraks

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I work with sodium hydroxide very often and I fail to see what the problem is. Maybe if you purchased it as a powder, but I've never seen it for sale in that form. The stuff I use comes in pellets (I've also got KOH in flakes). Don't dip your hands in it for extended periods of time and evidently don't splash any into your eyes or on mucous membranes. But that's easy to ensure and valid advice for dealing with any kind of photochemistry.

Did you know sodium hydroxide is commonly sold as drain cleaner? It's intended for use by private individuals without any chemical training and evidently outside a lab setting.
 

Alain Deloc

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Now the real question is : will DTPA (or DTPA-Na5 salt) manage to protect the Xtol-patent formula from sudden failure? I used DTPA-Na5 in Ron Mowrey's C41 formula (Photo Engineer) and 1L of this developer lasted for 1 year. I developed a Fuji Superia (roll #11) with it a week ago and went out perfect. But it's true also that C41 doesn't have any ascorbate and CD4 is also protected by HAS. Did anyone try to mix this Xtol with DTPA?
 

koraks

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Alain Deloc said:
But it's true also that C41 doesn't have any ascorbate and CD4 is also protected by HAS.
Click to expand...

Well, there you go; it's mostly the HAS that protects the CD4. Whether CD4 is also sensitive to iron impurities like CD3, I don't know. I do know that Fuji RA4 developers contain chelating agents (not DTPA as I recall) likely for this very reason.

I've not tried mixing up mytol/xtol with DTPA since I just mix what I need and then discard. I've never found this to be a problem, either in terms of time or material cost. YMMV and I know your preferences are otherwise.
 
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