Hi there,
I got so much knowledge lurking into the discussions in this forum, and it is time I start sharing some of mine. I wanted to have some sort of reference developer with the idea of using it occasionally, and commercial Microphen seemed like a perfect candidate.
Commercial Ilford Microphen powder for 1 liter contains, according to the MSDS,
Part A (13.47 g) hydroquinone, phenidone, boric acid, sodium metabisulfite
Pat B (117.35 g) sodium sulfite, borax, sodium tripolyphosphate, potassium bromide
Obviously Ilford added chelator and sodium metabisulfite to the formula of ID-68, to protect hydroquinone and phenidone from oxidation during dissolution of Part A at high temperature. Thus, there is more borax in part B to compensate for added bisulfite. Its amount is somewhat uncertain since it comes in several hydrated forms, and it is unknown which one Ilford used. I thought this formulation is a perfect candidate for a two solution “long-lived” developer that can be prepared without any additional chemicals (well, not quite, read on).
First, I warmed 200 ml of water to 50 degree Celsius, and attempted to dissolve Part A contents in it. Some pellet remained, which is likely phenidone, so I carefully decanted most of the solution into another jar, and added 10 ml of rubbing alcohol, and after slight mixing the pellet dissolved. I returned the remainder of the Part A solution into this jar and mixed. The resultant concentrate is clear and colorless, is 5X with regard to the stock developer and contains ~3.5% isopropanol. This solution has pH of 5. It was distributed into 4x50 ml tubes, each of 3 filled to the top, and the last one had 20 ml left.
Solution B, containing a lot of sulfite cannot be concentrated, so it was dissolved in 800 ml volume and was dispensed in glass beer bottles with rubberized spring-latch caps, 400 ml each.
For preparation of working developer one needs to mix 50 ml of solution A and 200 ml of solution B.
For 1:1, take 125 ml water, 25 ml solution A and 100 ml solution B. Given that the stock is rated for 10 films, using 1:1 as one shot allows to develop 8 films, using every time a fresh solution. So far this works perfectly after 3 months and counting. Both solutions are still colorless and the development time is the same. Example: Kentmere 100, 10 min at 20 C in 1:1.
Now, obviously, this principle could be applied to a variety of powder developers of the same family (D-76, ID-11, Perceptol etc), but I have no interest in testing all of them. Incidentally, this two-solution preparation also opens a venue for additional experimentation, as in how this developer would work in the near absence of sulfite, with different alkaline buffers and so on. I hope someone would find this helpful.
I got so much knowledge lurking into the discussions in this forum, and it is time I start sharing some of mine. I wanted to have some sort of reference developer with the idea of using it occasionally, and commercial Microphen seemed like a perfect candidate.
Commercial Ilford Microphen powder for 1 liter contains, according to the MSDS,
Part A (13.47 g) hydroquinone, phenidone, boric acid, sodium metabisulfite
Pat B (117.35 g) sodium sulfite, borax, sodium tripolyphosphate, potassium bromide
Obviously Ilford added chelator and sodium metabisulfite to the formula of ID-68, to protect hydroquinone and phenidone from oxidation during dissolution of Part A at high temperature. Thus, there is more borax in part B to compensate for added bisulfite. Its amount is somewhat uncertain since it comes in several hydrated forms, and it is unknown which one Ilford used. I thought this formulation is a perfect candidate for a two solution “long-lived” developer that can be prepared without any additional chemicals (well, not quite, read on).
First, I warmed 200 ml of water to 50 degree Celsius, and attempted to dissolve Part A contents in it. Some pellet remained, which is likely phenidone, so I carefully decanted most of the solution into another jar, and added 10 ml of rubbing alcohol, and after slight mixing the pellet dissolved. I returned the remainder of the Part A solution into this jar and mixed. The resultant concentrate is clear and colorless, is 5X with regard to the stock developer and contains ~3.5% isopropanol. This solution has pH of 5. It was distributed into 4x50 ml tubes, each of 3 filled to the top, and the last one had 20 ml left.
Solution B, containing a lot of sulfite cannot be concentrated, so it was dissolved in 800 ml volume and was dispensed in glass beer bottles with rubberized spring-latch caps, 400 ml each.
For preparation of working developer one needs to mix 50 ml of solution A and 200 ml of solution B.
For 1:1, take 125 ml water, 25 ml solution A and 100 ml solution B. Given that the stock is rated for 10 films, using 1:1 as one shot allows to develop 8 films, using every time a fresh solution. So far this works perfectly after 3 months and counting. Both solutions are still colorless and the development time is the same. Example: Kentmere 100, 10 min at 20 C in 1:1.
Now, obviously, this principle could be applied to a variety of powder developers of the same family (D-76, ID-11, Perceptol etc), but I have no interest in testing all of them. Incidentally, this two-solution preparation also opens a venue for additional experimentation, as in how this developer would work in the near absence of sulfite, with different alkaline buffers and so on. I hope someone would find this helpful.
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