DS-10

[eclarke]

Hi All,
I have happily mixed about 16 liters of DS-10 but this weekend the batch turned pink!! I am mixing with a magnetic stirrer and mixing the chemicals in order...the salicylic acid dissolved in methyl alcohol 10%...clean pyrex glass. What can cause this??..Thanks..Evan

 

[Gerald Koch]

Is this the first time you have used salicylic acid dissolved in alcohol or have all former batches been mixed the same way?

BTW, is you are using a magnetic stirrer then salicylic acid should dissolve easily after the TEA is added and you really don't need the alcohol.

 

[eclarke]

Is this the first time you have used salicylic acid dissolved in alcohol or have all former batches been mixed the same way?

BTW, is you are using a magnetic stirrer then salicylic acid should dissolve easily after the TEA is added and you really don't need the alcohol.

Hi Gerald,
The first 2 2liter batches were mixed all-in and I had an awful time with dissoving the salicylic acid. The next 6 2liter batches used the solution and were just fine, ingredients mixed in order, the one yesterday turned pink. It has been about 2 weeks since I made the solution. I will mix tonight as you suggest and see if the acid dissolves. I am using a 2 liter pyrex beaker to mix in and I am pretty fussy about cleaning it and it has only been used for DS-10 thus far..Thanks for the post..Evan Clarke

 

[Gerald Koch]

My first thought was perhaps some additive in the alcohol. But your answer rules this out. One of the oxidation products of phenidone, and I would also assume of Dimezone S, is pinkish in color. Salicylic acid forms a reddish chelate with iron. Is there anything different about with batch. A new supply of a particular chemical?

Avoid too much agitation as this encourages oxidation particularly with an open container such as a beaker. Something like an Ehrlenmeyer flask would be a better choice since it can be stoppered between chemical additions thus limiting exposure to oxygen while stirring.

 

[eclarke]

My first thought was perhaps some additive in the alcohol. But your answer rules this out. One of the oxidation products of phenidone, and I would also assume of Dimezone S, is pinkish in color. Salicylic acid forms a reddish chelate with iron. Is there anything different about with batch. A new supply of a particular chemical?

Avoid too much agitation as this encourages oxidation particularly with an open container such as a beaker. Something like an Ehrlenmeyer flask would be a better choice since it can be stoppered between chemical additions thus limiting exposure to oxygen while stirring.

Agitation time may be the culprit, I stirred this a fairly long time while I was doing other duties. All chemicals are from the same lots, the water is reverse osmosis, filtered through 4 cartridges. There is only .3 grams of Dimezone S per 2 liter batch..Thanks For the post..Evan Clarke

 

[Ryuji]

Hi All,
I have happily mixed about 16 liters of DS-10 but this weekend the batch turned pink!! I am mixing with a magnetic stirrer and mixing the chemicals in order...the salicylic acid dissolved in methyl alcohol 10%...clean pyrex glass. What can cause this??..Thanks..Evan

Did you forget to add ascorbic acid?

 

[eclarke]

Did you forget to add ascorbic acid?

I don't think so, but I am starting to suffer from the ravages of senior citizenship and anything could be possible. When I posted about this before and asked about dissolving in alcohol, you stated that I should not have much difficulties dissolving the salicylic acid if I mixed in order. By that time, I had solution made and was stuck in that mindset. I am going to make 2 batches tonight, one mixing in order without the solution and one with, using a check-off list to make sure I don't forget anything and I will stay with it until it is in solution so there is no over agitation. I have about 30 sheets that I don't want to experiment on or I would have just tried the stuff in it's pink state..you never know..Thanks..Evan

 

[Richard Wasserman]

Evan,
I have been following your tribulations with DS-10 and I'm afraid that I really don't have much to offer except that I've mixed and used a lot of it without any problems. I've never had any trouble getting any of the ingredients to dissolve and I've never done anything special-no alcohol, no magnetic stirrers. I hope you can figure out what is causing your problems as it is really a nice developer.

Richard Wasserman

 

[eclarke]

Thanks Richard..It is a really good developer. Ryuji..I have made 2 batches and there is no question that I forgot the ascorbic acid. One batch used the solution and the other batch was mixed in order as per the formula and all chemicals dissolved properly. I was lulled by the ease of mixing DS-2 with the chemicals thrown all in,it's a great developer for Tmax 100...Thanks all.. problems gone and I will not bother with this again (tonight)....Evan

 

[john_s]

......... Salicylic acid forms a reddish chelate with iron...........

Salicylic acid slowly goes red in glycerine which is a triol and somewhat related to alcohol. I know this because a pharmacist advised me to use some glycerine to help mix salicylic acid into a home made skin perparation. Salicylic acid is used to treat skin solar keratoses, common here (Oz, the skin cancer capital of the world). My salicylic acid was fresh from Merck, and the glycerine was the common pharmacological grade.

I would add that whenever chemicals are mixed there is scope for a reaction. It's only occasionally that we are alerted by a colour change.

I would be inclined to grind the salicylic acid very finely with a mortar+pestle. They can be found cheaply on Ebay. My salicylic acid was in flaky crystals, making it more difficult to dissolve than fine powder.

 

[Ryuji]

Ummm.... My salicylic acid is fine dusty powder...

The reason why I suspected omission of ascorbic acid is that, phenidone-type developing agents make very colorful solution when partially oxidized radical forms are generated, and it is a particular property of phenidone type agents that the radical forms are stable for rather long time. So if phenidone type agent is dissolved before ascorbate or HQ is dissolved, the solution may often look pink, red, or sometimes greenish blue color depending on the condition. But the color due to this effect goes right away as soon as ascorbic acid is dissolved. But if Evan excluded this possibility, I have no explanation. Whether small amount of alcohol is used or not, etc... may make difference in the ease of preparing the solution but the resulting solution should be clear, at least in my hand.

 

[eclarke]

Ummm.... My salicylic acid is fine dusty powder...

The reason why I suspected omission of ascorbic acid is that, phenidone-type developing agents make very colorful solution when partially oxidized radical forms are generated, and it is a particular property of phenidone type agents that the radical forms are stable for rather long time. So if phenidone type agent is dissolved before ascorbate or HQ is dissolved, the solution may often look pink, red, or sometimes greenish blue color depending on the condition. But the color due to this effect goes right away as soon as ascorbic acid is dissolved. But if Evan excluded this possibility, I have no explanation. Whether small amount of alcohol is used or not, etc... may make difference in the ease of preparing the solution but the resulting solution should be clear, at least in my hand.

Hi Ryuji,
No question about it, I DID forget the ascorbic acid in the pink batch. I keep all the formulas on a laptop in my blending area and when I decided to make a paper check list last night, I skipped right past the ascorbic acid while writing the ingredients down. My senile memory flashed and it is a certainty that I mixed wrong. So I could have added ascorbic acid and gone on to use the batch??
It's funny, I design and build products and machinery as a profession and am usually very orderly. I got off on the wrong track with my procedure when I discovered the DS-2 and the notion I could just dump everything and mix it, I think the DS-10 needs a little better method than I was using.
I am using some Efke PL25 in 4x5 and 5x7. Could you make a developer recommendation?? Thank you very much for allowing us access to your knowledge..Evan Clarke

 

[Gerald Koch]

I once mixed a batch of D-76 and was pouring it into a bottle when I noticed the paper with the weighed Metol on it. I discovered that Metol will dissolve in sulfite solutions with a lot of stirring if the water is hot enough.

I have been considering keeping a lab notebook again and recording in it as I weigh out each ingredient. This way there's an easy check to see if everthing has been weighed out properly and added to the solution.

 

[eclarke]

I once mixed a batch of D-76 and was pouring it into a bottle when I noticed the paper with the weighed Metol on it. I discovered that Metol will dissolve in sulfite solutions with a lot of stirring if the water is hot enough.

I have been considering keeping a lab notebook again and recording in it as I weigh out each ingredient. This way there's an easy check to see if everthing has been weighed out properly and added to the solution.

I was filling out an index card in order to do just that when I discovered I was jumping past the ascorbic acid almost automatically when reading from my laptop. I am going completely analog on my formulas from here on out!!..Evan