Switch to English Language Passer en langue française Omschakelen naar Nederlandse Taal Wechseln Sie zu deutschen Sprache Passa alla lingua italiana
Members: 71,840   Posts: 1,582,476   Online: 802
      
Page 4 of 5 FirstFirst 12345 LastLast
Results 31 to 40 of 46
  1. #31

    Join Date
    May 2005
    Location
    Woonsocket, RI USA
    Shooter
    35mm
    Posts
    2,725
    Quote Originally Posted by pauldc
    1. Since the thread was written how are people getting on with this non-TEA PC developer? I am particularly interested in using it with FP4+ as I have heard that it is the closest thing to my dearly departed Paterson Acutol!
    I've never used Acutol, so I can't comment on results from Gainer's developers compared to it. I can say this, though: Just a couple of hours ago I processed a roll of Fomapan 200 in PC-Glycol (as described in Gainer's PT article) 1+1+48. I mixed it originally in May of 2005, so it's over a year old, and it's still working fine. I used Dimezone S rather than phenidone in mine, though, and that could improve the longevity of the solution. I've used PC-Glycol with several films, including Fomapan 200, Fomapan 400, Ilford Pan F+, and Svema FN64, and it's worked well with all of them.

    Quote Originally Posted by pauldc
    2. I am confused by the seemingly different ratios of Phenidone and Vit C in the non TEA recipe to the original TEA recipe.
    The formulas I've got are:

    PC-Glycol:
    Stock "A":
    ascorbic acid: 10g
    phenidone: 0.25g
    propylene glycol to make: 100ml

    Stock "B":
    sodium carbonate, anhydrous: 15g
    water to make: 100ml

    Use 1+1+48; developing times roughly 10% greater than XTOL 1+1 times (based on personal experience). You can experiment with the stock "B" solution (use borax, for instance), if you like.

    PC-TEA:
    triethanolamine, 99%: 100ml
    ascorbic acid: 9g
    phenidone: 0.25g
    water to make: 0.1l

    Use 1+50. I have no developing time data handy (I've never used it).

    In terms of the ascorbic acid/phenidone ratios, they're similar, but not identical (10:0.25 for PC-Glycol and 9:0.25 for PC-TEA). I've seen the formulas on some Web sites (such as this one) with slightly different numbers. Mine are from the original article (unless I erred in copying them, which is always possible). I believe Pat Gainer has done some tests on the optimum ratio of ascorbic acid to phenidone, but I don't recall the results.

  2. #32

    Join Date
    Dec 2004
    Shooter
    Multi Format
    Posts
    1,670
    If you substitute one of the other phenidones; Phenidone B, Dimezone, or Dimezone S be aware that a 1:1 substitution will not produce the same developer activity. Not only must you compensate for the increased molecular weight but the substituted phenidones have a lower activity. So when substituting Dimezone S for Phenidone you should really use at least 1.4 times as much Dimezone S to produce a developer that has the same activity as the Phenidone version.

  3. #33

    Join Date
    Mar 2004
    Location
    Southern California
    Shooter
    Multi Format
    Posts
    3,879
    Images
    11
    Quote Originally Posted by srs5694
    .. I used Dimezone S rather than phenidone in mine, though, and that could improve the longevity of the solution...
    If the solvent was glycol, I would not expect any change in the longevity of the stock solution due to your use of Dimezone S instead of Phenidone.

    My stock solution, mixed in Propylene Glycol with Phenidone is still fully active after 3+ years.
    Tom Hoskinson
    ______________________________

    Everything is analog - even digital :D

  4. #34

    Join Date
    Sep 2004
    Location
    Toronto, Canada
    Shooter
    Multi Format
    Posts
    587
    Quote Originally Posted by srs5694
    In terms of the ascorbic acid/phenidone ratios, they're similar, but not identical (10:0.25 for PC-Glycol and 9:0.25 for PC-TEA). I've seen the formulas on some Web sites (such as this one) with slightly different numbers. Mine are from the original article (unless I erred in copying them, which is always possible). I believe Pat Gainer has done some tests on the optimum ratio of ascorbic acid to phenidone, but I don't recall the results.
    The site you link to is mine. The formula for PC-Glycol that I posted there was given to me by Pat Gainer in an e-mail several years ago. I'm sure the one that got published in Photo Techniques was a refined version, but my PC-Glycol has been working fine. (My first batch lasted 2.5 years with no detectable loss in activity.)

    I make PC-TEA "in situ" by mixing equal parts PC-Glycol stock and triethanolamine.

  5. #35

    Join Date
    Dec 2004
    Shooter
    Multi Format
    Posts
    1,670
    Quote Originally Posted by gainer
    I think that BS about the propylene glycol becoming more poisonous than the ethylene is propaganda. I would like to hear from a professional chemist about the veracity of that statement.
    I have training as a professional chemist having a BS Chem and a MS. From a purely chemical viewpoint propylene glycol would seem safer than ethylene glycol since it is not metabolized to oxalic acid in the human body. However, this chemical must be evaluated from a toxicological perspective not merely a chemical one.

    It appears that propylene glycol is not as safe as once believed. Current literature reports several cases of reverseable kidney failure after the IV administration of drugs containing propylene glycol. A tentative safe level has now been set at 25 mg/kg of body weight although a toxic dose has not been established.

    Of all the solvents, other than water, that that we commonly use to prepare concentrated developers, propylene glycol is probably the safest. As with all chemicals do not ingest it and avoid breathing the vapor when heating it. Skin absorption does not appear to be a problem but avoid eye contact.

  6. #36

    Join Date
    Mar 2003
    Location
    Greenville, SC
    Shooter
    Large Format
    Posts
    4,813
    Images
    5
    I have seen various activators suggested for PC-Glycol, including sodium carbonate, sodium metaborate, and a combination of the two. Can someone tell me which of the activators gives results closest to those from PC-TEA in terms of developer energy, i.e. speed of development?

    Sandy

  7. #37

    Join Date
    Dec 2004
    Shooter
    Multi Format
    Posts
    1,670
    Quote Originally Posted by sanking
    I have seen various activators suggested for PC-Glycol, including sodium carbonate, sodium metaborate, and a combination of the two. Can someone tell me which of the activators gives results closest to those from PC-TEA in terms of developer energy, i.e. speed of development?

    Sandy
    I have always used TEA as the activator. From a purely chemical standpoint, sodium metaborate will produce a pH closer to TEA than sodium carbonate. But this pH will still be higher than that produced by the TEA.
    For comparison, the pH values for 1% solutions of TEA, metaborate, and carbonate are respectively, 9.8, 11.1, and 11.4.

  8. #38
    gainer's Avatar
    Join Date
    Sep 2002
    Posts
    3,726
    Images
    2
    If you buy it by the gallon, TEA from The Chemistry Store is about $16 per gallon + shipping. It is handy stuff to have around, as is propylene glycol.

    Anything can be dangerous. You can drown in a remarkably small amount of water. Most chemicals we use can easily be handled safely. The first time a child comes near the darkroom chemicals, a little application of knowledge at the seat of learning can stress the dangers.
    Gadget Gainer

  9. #39

    Join Date
    May 2005
    Location
    Woonsocket, RI USA
    Shooter
    35mm
    Posts
    2,725
    Quote Originally Posted by gainer
    If you buy it by the gallon, TEA from The Chemistry Store is about $16 per gallon + shipping. It is handy stuff to have around, as is propylene glycol.
    This thread got a renewed lease on life because of a post from somebody in the UK who can't seem to find TEA locally. Although TCS is a good supplier in the US, intercontinental shipping is likely to be impractical (if TCS would even do it; I haven't checked on this detail).

    Anything can be dangerous. You can drown in a remarkably small amount of water.
    There are various joke Web sites that talk about the dangers of "dihydrogen monoxide" (water by another name, of course). People sometimes take these seriously and make fools of themselves trying to get this "dangerous substance" banned.

  10. #40

    Join Date
    Sep 2004
    Location
    Toronto, Canada
    Shooter
    Multi Format
    Posts
    587
    Quote Originally Posted by sanking
    I have seen various activators suggested for PC-Glycol, including sodium carbonate, sodium metaborate, and a combination of the two. Can someone tell me which of the activators gives results closest to those from PC-TEA in terms of developer energy, i.e. speed of development?
    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.

Page 4 of 5 FirstFirst 12345 LastLast


 

APUG PARTNERS EQUALLY FUNDING OUR COMMUNITY:



Contact Us  |  Support Us!  |  Advertise  |  Site Terms  |  Archive  —   Search  |  Mobile Device Access  |  RSS  |  Facebook  |  Linkedin