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Order matters!
The order that ingredients are dissolved into a propylene glycol-based concentrate is important!
I made more concentrate today, and followed my formula in this order (at about 90C):
Order 1: propGlycol=24ml, s.metaborate=6.7g, ascorbicAcid=8.5g, dimezoneS=.2g
The clear liquid turned yellow upon adding the dimezone. Then it became cloudy, with lines of chemical-scale appearing on the bottom and sides of the beaker and growing. After a few more minutes, the bottom was almost entirely covered with scale. The solution ended up being thickly cloudy with what seems to be fine particles. And highly viscous.
This is similar to what happened in Feb 2012 after creating a highly concentrated concentrate. After a few days, some cloudy streaks appeared in it, and it became completely cloudy upon heating, and ended up looking like milk. Also highly viscous. Here's my posting about it from Feb 2012:
http://www.apug.org/forums/archive/i...8430-p-22.html
My query is the sixth posting.
So I changed the order to this, completely dissolving each before adding the next: (still at about 90C)
Order 2: propGlycol=24ml, dimezoneS=.2g, s.metaborate=6.7g, ascorbicAcid=8.5g
I got the same behavior I mentioned a couple of days ago: The solution turned orange upon adding metaborate, and clear again upon adding ascorbic acid, and it fizzed upon adding the ascorbic acid, with visible foam.
With the clear-to-orange, and orange-to-clear, and fizzing, it's obvious that reactions are occurring in the propylene glycol solution in Order 2. Also, the yellowing and cloudiness and scale and high viscosity are different reactions occurring in Order 1.
Do the chemists here have any idea why dissolving the DimezoneS first versus last makes such a large difference?
Mark Overton
PS @Kirk: Okay, I won't bother if a pH-difference is small. One trick I use is to quickly go back and forth between my test-developer and XTOL (known to be 8.29). Think of it as a minute-by-minute calibration. I've been able to get repeatability within +/- 0.02 doing this. But getting that initial measurement of XTOL requires a real calibration, which one hopes will stay true for half an hour.
Last edited by albada; 07-15-2012 at 12:38 AM. Click to view previous post history.
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With Order 2, when you say the solution turned orange, do you mean an orange precipitate formed, or merely that the solution color turned orange AND was still clear.
Kirk
For up from the ashes, up from the ashes, grow the roses of success!
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 Originally Posted by Kirk Keyes
With Order 2, when you say the solution turned orange, do you mean an orange precipitate formed, or merely that the solution color turned orange AND was still clear.
The latter: The solution became orange colored, but remained clear with no cloudiness or precipitate. It looked like some drops of dye had been mixed in.
Note that Kodak's XTOL becomes light orange after mixing the first packet, and becomes clear after mixing the second packet.
Mark Overton
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Mark, first I'm note that your experiments is very interesting for me.
The solution turned orange upon adding metaborate,
metaborate is alkali. orange color because phenidone oxidized by metaborate
and clear again upon adding ascorbic acid, and it fizzed upon adding the ascorbic acid, with visible foam.
ascorbic acid with metaborate produce sodium ascorbate, which recover oxidized phenidone.
I don't understand why you need to mix metaborate with phenidone/ascorbic acid. Try to make concentrate as follow
part A: glycol+phenidone+ascorbic acid
part B: water+metaborate+sulfite
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I also agree that it's pain to dissolve inorganic compounds into organics.
The fizzing indicates that there is a bit of carbonate present and when you add the ascorbic acid, it's released from the solution.
Kirk
For up from the ashes, up from the ashes, grow the roses of success!
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Metaborate does not oxidize phenidone.
Phenidone is being oxidized and then is being reduced by ascorbate. This is often seen when mixing other developers and is why a pinch of sulfite is added. Doing that here woulb be a pain.
PE
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Success with Ilford HP5+
I've done all my testing with TMY2. This time, I wanted to compare this concentrate with XTOL using a film that was not made by Kodak, and not T-grain. And I wanted to test development of an entire roll, not just a short strip, to see if there is a capacity-issue. So I exposed and developed two 36-shot rolls of HP5+, and here are their curves:
They match nicely. That tells me that this concentrate can handle a variety of film-chemistries. Both rolls were developed identically: 220 ml of stock developer for 8 minutes at 20C (Ilford's recommendation).
Grain looks the same in my 22X loupes. I also took some tripod-shots outdoors, so you'll soon see some scans that'll let you gauge both grain and sharpness.
Mark Overton
EDIT: Evidently, the orange phenomenon described earlier is damaging the Dimezone S little, if at all. The concentrate is closely following XTOL, as it did when its ingredients were mixed directly into water (with my TMY2 tests).
Last edited by albada; 07-15-2012 at 08:44 PM. Click to view previous post history.
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Make certain you do some push processing / N+ developments in your tests to make sure there's enough there to get the job done.
Kirk
For up from the ashes, up from the ashes, grow the roses of success!
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Nice work, Mark, and thank you for the hours in the basement!
The curious color changes seem to indicate there is enough water in the system to allow the phenidone to react. I note you heat the PG etc after mixing to remove any water. To exclude water in the PG (unlikely) and the metaborate could you not mix them first, then heat to dry out before adding the rest?
Just a thought.
Murray
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