Color of Metol?

[Tom Taylor]

A few days ago I mixed 120mL of Defender 59-D stock, stored it in a 250mL brown glass bottle for a couple of days, and then used it in a printing session diluted 1:3 (480mL of working solution). I wasn't paying close attention to its color but it was on the clear side. The image started coming-up in about 22 seconds initially and in about 32 seconds towards the end of the session. Image quality was excellent and what I was hoping for. So, 2 days ago I mixed up 250mL of stock, stored it in the same brown glass bottle, and mixed 1/2 of it for a working solution of 500mL. This time, however, the color of the stock was a dark brown as seen in the beaker on the right. A faint image appeared in about 1'30". I tossed the developer and switched to Dektol which I managed to drain from the floating tank. After the session I mixed a few gms of Metol with distilled water in the small beaker shown on the left and left it overnight. Initially the color was clear but changed to the pinkish color in the morning. The Metol powder is shown in the petri dish and it appears to be white under strong illumination. Since the first batch worked fine, it's possible that I combined the wrong chemicals for the 2d batch. But that doesn't sound plausible since I am normally careful when mixing chemistry. What do you think?

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[Don_ih]

Metol will oxidize rapidly in water, so it would be totally dead if in a beaker overnight like that. You sprinkle a pinch of sodium sulphite into the water before you add metol to stop the metol from oxidizing from the oxygen dissolved in the water (the sulphite prevents that).

As a powder, metol varies from white to kinda tan. Any darker might indicate it's gone bad, but I saw someone here who said his brown metol worked fine.

I have no idea why your developer would get that brown.

 

[Tom Taylor]

Thanks for the quick reply Don. Are you saying that the pink color indicates that the Metol has oxidized? In the future I'm going to add a little sulfite before adding the Metol but that didn't have any effect on the first batch I mixed.

I wonder if I grabbed the Sulfate instead of the Sulfite? Mistakes like that are common amongst us seniors.

 

[koraks]

Sounds like a mixing error somewhere in the process. Forgot the sulfite, maybe? The metol will oxidize pretty rapidly in the alkaline environment of a developer formulation if no antioxidant is present.

Are you saying that the pink color indicates that the Metol has oxidized?

If that beaker has a few grams of metol in it and it's only slightly pink, I'd call it barely oxidized. Hardly significant. Fully oxidized, the beaker on the left would look like the one on the right.

 

[Don_ih]

I wonder if I grabbed the Sulfate instead of the Sulfite?

If you have Sodium Sulfate, it's really easy to mix them up. I have very thick black marker circles around the words Sodium Sulfate on the bottle I have.

I don't know what metol in solution looks like totally oxidized, because I have never tried to do it.

 

[Tom Taylor]

Thanks for the reply Koraks. Hopefully I did add sulfate instead of sulfite. Both bottles were in a prominent frontal location on the shelf which indicates recent use but I use sulfite often but not so often for sulfate. Easy to confuse them. The Dektol drained from the tank had darken indicating oxidation but worked fine with the image coming up in about 10 seconds. With the price of Dektol doubling to $20 a gallon I'm planning on mixing D-72 to save bucks.

 

[mshchem]

Thanks for the reply Koraks. Hopefully I did add sulfate instead of sulfite. Both bottles were in a prominent frontal location on the shelf which indicates recent use but I use sulfite often but not so often for sulfate. Easy to confuse them. The Dektol drained from the tank had darken indicating oxidation but worked fine with the image coming up in about 10 seconds. With the price of Dektol doubling to $20 a gallon I'm planning on mixing D-72 to save bucks.

Good idea to make your own. Speaking of senior moments, I thought I had completely rewound a roll of Fujichrome a couple days ago. Opened up the camera to find most of the roll Not rewound!

 

[Doremus Scudder]

It makes sense that you left out the sulfite or used sulfate instead. It's the sulfite that keeps the Metol from oxidizing and turning dark brown. The fact that it did indicates that oxidation happened and that the anti-oxidant was not present.

Mix new, being careful to use the sulfite, and see what happens.

Doremus

 

[Tom Taylor]

I mixed up another batch after posting yesterday double checking that I had the right chemistry and the solution is clear as of this morning. Right at the beginning of the Covid pandemic I had cataract surgery choosing the “distance” option for the lenses. The surgery was successful and 3 years later my distance vision is perfect, 20/20 and 20/25, so I didn't need glasses to renew my drivers license and can readily make out patterns in the night sky. However the near distance really suffered and I can no longer see clearly close-up without using reading glasses. That's what I think happened. “Sulfate” and “Sulfite” looks similar so I'm going to take Don's suggestion above and mark the bottle containing the sulfate so I don't make that mistake again.

 

[mshchem]

I mixed up another batch after posting yesterday double checking that I had the right chemistry and the solution is clear as of this morning. Right at the beginning of the Covid pandemic I had cataract surgery choosing the “distance” option for the lenses. The surgery was successful and 3 years later my distance vision is perfect, 20/20 and 20/25, so I didn't need glasses to renew my drivers license and can readily make out patterns in the night sky. However the near distance really suffered and I can no longer see clearly close-up without using reading glasses. That's what I think happened. “Sulfate” and “Sulfite” looks similar so I'm going to take Don's suggestion above and mark the bottle containing the sulfate so I don't make that mistake again.

Good to hear. I need to mark my bottles

 

[Tom Taylor]

The mishap may have proved beneficial. The negative I was working on was a high contrast one due to sunlight and shadow throughout the scene. I split-grade printed it on Ilford Satin using a 0 and 5 filter and ended-up with a fairly good image except for one overexposed strip due to the sunlight falling there. The loup showed that there was detail there so I burned that area in with the 0 filter and got a little of the detail out but not enough – it was still too bright. I then tried dodging with the 0 filter but the area got brighter (as I expected). Then I burned the area with a 5M filter and got the best result up to that time. But it was getting late – past 2am- and the developer was beginning to fade. So I called it quits for the night and then ran into the mixing problem the next. But I have some Ilford Art 300 which I am going to try when I get back to the darkroom which “may” do the trick without any further burning with the 5M and compliment the negative and developer. Dektol produced a harsher print which I am not looking for.

 

[Donald Qualls]

FWIW, I have some Dektol stock (probably finally time to dump it) that I mixed in 2005 at double strength, and it's about the same color as your right hand beaker. It still worked last time I used it (at 1+9 for film) in 2019. Then again, that's MQ rather than metol alone; the HQ being superadditive means any remaining metol will have more effect than it would without the HQ.

 

[Don_ih]

I have some Ilford Art 300 which I am going to try

I find Ilford Art has higher natural contrast than MGFB --- maybe not more than Ilford rc papers. Anyway -- make sure you use acid stop on the Art 300. I tested it and it needs about a full minute in acid stop prior to fixing to prevent staining (the paper absorbs developer like a sponge and active developer + fixer = silver staining in the paper).