Switch to English Language Passer en langue française Omschakelen naar Nederlandse Taal Wechseln Sie zu deutschen Sprache Passa alla lingua italiana
Members: 69,983   Posts: 1,523,905   Online: 1043
      
Page 2 of 3 FirstFirst 123 LastLast
Results 11 to 20 of 30
  1. #11
    Ian Grant's Avatar
    Join Date
    Aug 2004
    Location
    West Midlands, UK, and Turkey
    Shooter
    Multi Format
    Posts
    16,220
    Images
    148
    A note about C41 and E6 developers, apart from amateur kits they are designed for continuous replenishment and the consequent build up of Bromide and Iodide.

    Ian

  2. #12

    Join Date
    Feb 2010
    Location
    Montreal, Canada
    Shooter
    Multi Format
    Posts
    4,554
    Quote Originally Posted by Rudeofus View Post

    PS: If Bromide had no effect on Phenidone based developers, then please someone explain me why they put it in E6 FD. And in Crawley's FX-37. And in ID-68 aka Microphen ...
    Rudi, you're correct bromide does restrain Phenidone at the pH values typical of fine grain developers. At higher pH values Phenidone is less sensitive to bromide and BZT is more effective (hence it's use in Phenidone-based print developers).

    As for FX-37 on the other hand (which contains both bromide and BZT) I believe the presence of bromide has more to do with Crawley's view that it improves definition in developers containing borate alkalis (which FX-37 does, along with Carbonate).

  3. #13
    Ian Grant's Avatar
    Join Date
    Aug 2004
    Location
    West Midlands, UK, and Turkey
    Shooter
    Multi Format
    Posts
    16,220
    Images
    148
    Quote Originally Posted by Michael R 1974 View Post
    Rudi, you're correct bromide does restrain Phenidone at the pH values typical of fine grain developers. At higher pH values Phenidone is less sensitive to bromide and BZT is more effective (hence it's use in Phenidone-based print developers).

    As for FX-37 on the other hand (which contains both bromide and BZT) I believe the presence of bromide has more to do with Crawley's view that it improves definition in developers containing borate alkalis (which FX-37 does, along with Carbonate).
    No Michael that's where you're wrong. Ilford did a lot of research into the effects of Bromide on MQ and the equivalent PQ fine grain developers (ID-11/D76 variations) and the PQ versions are remarkably tolerant of Bromide build up which has far less effect on restraining development.

    Ian

  4. #14
    Athiril's Avatar
    Join Date
    Feb 2009
    Location
    Melbourne, Vic, Australia
    Shooter
    Medium Format
    Posts
    2,495
    Images
    28
    Bromide isn't speed losing, it's contrast increasing by lowering density, more at the lower exposure scale than the higher scale. It's all in how you use it.

  5. #15

    Join Date
    Feb 2010
    Location
    Montreal, Canada
    Shooter
    Multi Format
    Posts
    4,554
    Quote Originally Posted by Ian Grant View Post
    No Michael that's where you're wrong. Ilford did a lot of research into the effects of Bromide on MQ and the equivalent PQ fine grain developers (ID-11/D76 variations) and the PQ versions are remarkably tolerant of Bromide build up which has far less effect on restraining development.

    Ian
    Ian, Phenidones are indeed less sensitive to bromide than Metol, but there is still some restraining action. Most mildly alkaline PQ developers would produce higher fog than comparable MQ equivalents without some KBr in the formula.

  6. #16

    Join Date
    Feb 2014
    Shooter
    35mm RF
    Posts
    17
    Thanks for the replies

    Rudeofus
    What dyou mean with?
    "There is no need to put the clip on the spindle, but make sure you have that black tube in your tank in the correct position, or light will come into the tank through the lid."

    ​I have one of these stainless steel ones. Can´t I open the small lid to pour the liquid in?

    Although I´m still not sure as of what to do.
    I don´t really have a stock of old films to test with, it was more a case of trying to put something in when I suspect the film might be fogged and then it´s a trial and error. But it might be that 2g/l is the way to go.
    Last edited by Auroraua; 03-15-2014 at 11:56 PM. Click to view previous post history.

  7. #17

    Join Date
    Sep 2006
    Location
    UK
    Shooter
    35mm RF
    Posts
    2,427
    @Auroral

    the plastic tanks need the tube but normally stainless are different.

    @Michael 19...

    Yea most of the Phenodine (and their analogs) formula's have halogen restrainers (as do some of the metol formula eg for D76 'clones'.

    But with some films the fog level in the MQ is higher and increases more rapidly with time, comparing ID11 and ID68.

    And as Ian mentioned replinisher rules can be different.

    But adding 1g/l to a PQ ID11 clone won't make much difference compared with a MQ variant so the restrainers are not independent of dev type (or independent of pH of a developer).

    I have oodles of old cine and use stock microphen or ID68 gave up on adding more restrainer simpler altering ISO a stop and dev for 15% less time, don't use MQ cause of skin problems.

  8. #18
    Rudeofus's Avatar
    Join Date
    Aug 2009
    Shooter
    Medium Format
    Posts
    1,559
    Images
    10
    Quote Originally Posted by Auroraua View Post
    Thanks for the replies

    Rudeofus
    What dyou mean with?
    "There is no need to put the clip on the spindle, but make sure you have that black tube in your tank in the correct position, or light will come into the tank through the lid."

    ​I have one of these stainless steel ones. Can´t I open the small lid to pour the liquid in?

    Although I´m still not sure as of what to do.
    I don´t really have a stock of old films to test with, it was more a case of trying to put something in when I suspect the film might be fogged and then it´s a trial and error. But it might be that 2g/l is the way to go.
    If you have no film to test a modified developer with, I'd say leave out the extra restrainer and print/scan through the fog. As I mentioned before, there is no "correct" amount of restrainer for aged film, it is completely up to tests and experimentation.

    About the tank&lid: if you were to make tests, you want to use as little film and developer as possible. If you put a test clip onto the spindle of an inversion tank, you'd have to fill that tank with developer, which means 250 ml per test. If you instead put a small test clip onto the bottom of your tank and leave out the spool, you may get away with 50-80 ml of developer per test run. The note about the spindle is specific to plastic tanks: even if you leave out the spool, you must still put the spindle in its place or light will come into your tank. I don't know or use stainless steel tanks, so I can't tell you much about them.

    There is one way you could still do tests without sacrificing a whole roll: leave the first few image frames unexposed and use that area, clip by clip, for testing various amounts of KBr.
    Trying to be the best of whatever I am, even if what I am is no good.

  9. #19
    Rudeofus's Avatar
    Join Date
    Aug 2009
    Shooter
    Medium Format
    Posts
    1,559
    Images
    10
    Quote Originally Posted by Athiril View Post
    Bromide isn't speed losing, it's contrast increasing by lowering density, more at the lower exposure scale than the higher scale. It's all in how you use it.
    Athiril, if you need more exposure to reach b+f+0.1 density, and require less development to get the specified contrast, then you will most definitely lose a fair bit of ISO speed.
    Trying to be the best of whatever I am, even if what I am is no good.

  10. #20
    Photo-gear's Avatar
    Join Date
    Dec 2009
    Location
    Montréal (Québec)
    Shooter
    35mm
    Posts
    308
    Images
    9
    Quote Originally Posted by Ian Grant View Post
    PQ developers are tolerant to much higher Bromide levels, this is because the Bromide doesn't suppress the activity of the Phenidonne but it does suppress the Metol in MQ developers.

    This is particularly important where developers are replenished, Autophen a commercial PQ version of D76/ID-11 had far greater capacity and could be replenished by a topping up method rather than the bleed & top up needed with D76.ID-11.

    So Bromide is more effective in a PQ developer as a restrainer without causing any speed loss hendce why it's used in the developers you mention.

    Ian
    I have foggy a bulk roll (100') of expired Plus-X Pan [2003]. After reading your post, I am wondering what could be the formula for developping this film, using PQ developer + KBr. I wish I could get an answer to it. Thx!

Page 2 of 3 FirstFirst 123 LastLast


 

APUG PARTNERS EQUALLY FUNDING OUR COMMUNITY:



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