Switch to English Language Passer en langue française Omschakelen naar Nederlandse Taal Wechseln Sie zu deutschen Sprache Passa alla lingua italiana
Members: 70,328   Posts: 1,537,129   Online: 871
      
Page 2 of 3 FirstFirst 123 LastLast
Results 11 to 20 of 21
  1. #11
    Photo Engineer's Avatar
    Join Date
    Apr 2005
    Location
    Rochester, NY
    Shooter
    Multi Format
    Posts
    22,972
    Images
    65
    The Ferric EDTA is an oxidant, no matter what gas is used for storage.

    They may use a stabilzer, but whatever it is, it will reduce the oxidation potential of the Ferric ion and thereby slow the blix. If it slows the blix, then you have more retained silver or you must use longer fix times.

    I know of several chemicals that can be added to a blix that would essentially turn it off totally! It also makes it as stable as a hypo solution of the same composition without the iron salts. And, it makes it only a fix. That can be done, and no one would notice the difference except for having retained silver. It would make it a very expensive and complex bleach bypass.

    No, the bottom line is that both developer and blix should be multipart.

    The developing agent begins to decompose when dissolved in alkali. Kodak and others store the developing agent in an acidic part that is neutralized when mixed with the other two parts. The Hydroxyl Amine in the developer should also be stored as an acid for best keeping, or at least in a neutral solution.

    I'm afraid that Tetenal is going to run into shelf keeping problems with these single part kits. We already see an example here, and I think there have been other threads on this as well.

    PE

  2. #12
    hrst's Avatar
    Join Date
    May 2007
    Location
    Finland
    Shooter
    Multi Format
    Posts
    1,300
    Images
    1
    I sent email to Tetenal:

    Subject: Defective RA-4 blix

    Hello,

    I'm very disappointed in your product TETENAL RA-4 print kit 2,5l. There should be no reason to use monoconcentrate to help mixing. The blix has oxidant and reductant together and has too short shelf life in one concentrate.

    I have used two kits and the blix has somehow worked only occasionally. It has crud in it and the bleaching and fixing power is not sufficient. It can die before even getting to the final user. You should use two concentrates.

    I've now re-bleached and re-fixed a lot of my prints. Some of them are fine, some are not. This has caused me much work and hassle.

    Kind Regards,
    Antti Alhonen
    Finland.


    It may be true that the problem is known and accepted, because with normal RA-4 prints the problem may not be visible for an "average customer" (hobbyist) - at least when the print is examined in subtle room lighting for short periods. But the reversal process shows the problem in its full glory since all the silver is developed...

  3. #13

    Join Date
    Feb 2007
    Shooter
    35mm Pan
    Posts
    20
    A funny thing is, I tried bleach bypass processing for some RA-4 prints using Agefix and then compared the result by using this same exhausted blix. I noticed no obvious difference in the final result and I was wondering, why the images looked almost exactly the same .

  4. #14
    Photo Engineer's Avatar
    Join Date
    Apr 2005
    Location
    Rochester, NY
    Shooter
    Multi Format
    Posts
    22,972
    Images
    65
    Bleach bypass will fix the coating and leave silver in image areas. This degrades the color, sharpness and grain. An exhausted blix which can still fix, can have the same effect, but if it cannot fix properly then the image is just like a B&W image which is unfixed.

    If the fixer is not of the proper pH in bleach bypass, or when using a bad blix, then the dyes can suffer in both hue and stability.

    PE

  5. #15
    Domin's Avatar
    Join Date
    Oct 2006
    Location
    Warszawa, Poland
    Shooter
    Med. Format RF
    Posts
    204
    Quote Originally Posted by hrst View Post

    The blix I'm using now has quite large amount of solid matter in it. I have to rub it away when final washing the print... The previous Tetenal RA-4 kit didn't have this much crud in it.
    I got the same problem repeatedly. It seems that it happens when the blix concentrate is not quite fresh. Unfortunately there is no way of telling before you get the kit (you don't need to mix the crud shows at the bottom of concentrate) as there is no expiry date on it.

    I've been unable to clean kodak paper with E surface and its quite a chore to wipe it of F surface. Since that I've switched to minilab chemistry. If you find someone to share a bigger package or some minilab operator willing to sell some you get 5l of working solutions for the price of the amateur kit. And no crud as a bonus.

  6. #16

    Join Date
    Jun 2004
    Location
    South Norfolk, United Kingdom
    Shooter
    Multi Format
    Posts
    2,874
    Images
    62

  7. #17
    Domin's Avatar
    Join Date
    Oct 2006
    Location
    Warszawa, Poland
    Shooter
    Med. Format RF
    Posts
    204
    I'd gladly use Kodak chemistry but it seems it is not available in small packages here while shipping from abroad makes it to expensive. I don't print color very often so I do not have much choice.

  8. #18
    mts
    mts is online now
    mts's Avatar
    Join Date
    Feb 2004
    Location
    Los Alamos, NM
    Shooter
    Multi Format
    Posts
    335
    Images
    119
    If commercial chemistry isn't available, then consider using scratch-mix bleach and fix. There are many formulae available. While bleach does take a bit of rocket science to ensure archival dyes, fixers are quite standard and easy to mix from scratch. As PE has noted here before, blix one might consider blix bad when it is mixed. Separate bleach and fix is clearly the way to go.
    By denying the facts, any paradox can be sustained--Galileo

  9. #19

    Join Date
    Jun 2004
    Location
    South Norfolk, United Kingdom
    Shooter
    Multi Format
    Posts
    2,874
    Images
    62
    Domin,

    Fujihunt produce a small RA-4 5 litre kit which might be easier for you to obtain.

    Tom.

  10. #20
    decolorante's Avatar
    Join Date
    Nov 2009
    Location
    Faenza, Italy
    Shooter
    Med. Format Pan
    Posts
    15
    From images I found on Google, I see that the Tetenal Colortec RA-4 kit has blix in two separate concentrates in the 5 liter version, but the 2.5 liter version has just one. Maybe they separated concentrates in the bigger version to allow for better splitted mixing?

    I am going to get the 5 liter one.

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