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  1. #41

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    Quote Originally Posted by Jordan
    Sandy -- As Gerald mentioned, TEA itself would work just fine. (In practice, that's what I use.) Barring that, of the options you listed, metaborate on its own is closest. A mixture of metaborate and borax could probably be used to bring the pH of the working solution even closer to the PC-TEA working pH but I don't know the exact amounts that would be required.
    Hi Jordan,

    Thanks for your comments, and thanks also to Gerald for the pH data.

    OK, I mixed up some PC-Glycol this evening and ran a comparison test of it against a PC-TEA solution that I mixed some 2.5 years ago. For the PC-Glycol I used a 30% solution of sodium metaborate as the activator, and mixed the working 1:1:100. The PC-TEA was mixed 1:100. Both were developed for the same time and conditions. Development was rotary in tubes on motor base, i.e. with fairly fast rotation, ten minutes at 72º F.

    The negatives are dry now and the PC-Glycol negative has slightly more contrast, which I think is consistent witht Gerald's data that indicated the metaborate would work at a higher pH than TEA.

    Curves attached. BTW, the ES for this plot was set at 1.40 for a Pt./Pd. print, as you can see from the CI. For silver gelatin papers the ES would need to be much lower. Time permitting I will run families of curves for PC-TEA and PC-Glycol soon, which will of course provide much more meaningful data than just single curves.

    BTW, the film used for this test was some of the JandC ASA 100 film from China. John sent me this film more than two years ago, and it has been stored at room temperature since then. And it still has a B+F of around 0.09, quite remarkable. And especially since it has excellent expansion potential, as you can see from the curves.

    Sandy
    Attached Thumbnails Attached Thumbnails PC-TEA-PC-Glycol.jpg  
    Last edited by sanking; 08-18-2006 at 12:08 PM. Click to view previous post history.

  2. #42
    eclarke's Avatar
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    If you want easy, try Ryuji's DS2..it's a no brainer and I use my Xtol times for Tmax and Delta exactly. Results seem better than Xtol at a fraction of the cost and effort.
    For 2 liters (easier to measure than a 1 liter batch):

    water 1600ml
    sodium bicarbonate 2.0 g
    ascorbic acid 2.0 g
    metol 0.8 g
    sodium sulfite, anhydrous 40 g
    sodium carbonate, monohydrous 6.0 g
    water to make 2.0 liters

    I have lept this for a week without losing potency. All of Ryuji's published formulas work beautifully and I appreciate that he has made them available.....EC

  3. #43

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    I got great results from DS-2 as well, but even at 10x concentration, it lost activity in a few a days. Now I use MC-TEA plus 10g/sulfite per liter - fantastic sharpness, exceedingly fine grain. Substantial speed loss, but great for summer.

  4. #44

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    Quote Originally Posted by sanking
    And it still has a B+F of around 0.9, quite remarkable.
    That would be quite remarkable, but looking at your graphs, I bet you really meant "0.09"...

  5. #45

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    Quote Originally Posted by Kirk Keyes
    That would be quite remarkable, but looking at your graphs, I bet you really meant "0.09"...

    One of the good things about the APUG forum is that one has a day or so to edit mistakes. Thanks for pointing this one out.

    Sandy

  6. #46
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    Quote Originally Posted by Maine-iac View Post
    Hi Peter,

    Sorry I wasn't online for the past day or so; since I'm a clergyman, Sunday is a heavy workday for me.



    Larry
    and I thought we were not supposed to work on Sundays.

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