Switch to English Language Passer en langue française Omschakelen naar Nederlandse Taal Wechseln Sie zu deutschen Sprache Passa alla lingua italiana
Members: 71,900   Posts: 1,584,401   Online: 753
      
Page 5 of 6 FirstFirst 123456 LastLast
Results 41 to 50 of 52
  1. #41
    Photo Engineer's Avatar
    Join Date
    Apr 2005
    Location
    Rochester, NY
    Shooter
    Multi Format
    Posts
    23,544
    Images
    65
    Well, you see that they went the other way. You need more oxidant, not more fix power. They appear to have added more fix power. IDK, can't really do more than guess from this, but that is the way it appears. I am working on some examples.

    PE

  2. #42
    Photo Engineer's Avatar
    Join Date
    Apr 2005
    Location
    Rochester, NY
    Shooter
    Multi Format
    Posts
    23,544
    Images
    65

    How to live with a blix - or not.

    Yes, you can make a film blix!

    Now, let me explain the consequences and the reasons behind the problems.

    1. Ammonium Ferric EDTA only comes as a liquid of about 40% concentration or about 400 g/l.

    2. Ammonium Thiosulfate only comes as a liquid of about 60% concentration or about 600 g/l.

    3. Sodium salts of the above are less soluble and come as powders. They are far less active than the ammonium salts.


    Now, let us look at the E6 bleach and fix concentrates. The bleach itself consists of 2 bottles that total to approximately 3 Liters all on their own. The fixer consists of one bottle of 423 ml. Each of these makes up 1 gallon or 3.8 L of solution.

    If you mixed each one up and then mixed them together to make a blix, the resultant mixture would be 50% more dilute than the original leading to less activity.

    If you mix them together in 1 gallon (3.8 L) then they have the same working strength as desired in separate bleach and fix, but the oxidation and reduction power of the two main ingredients conflict and the solution becomes short lived (less than a month, perhaps less than a week).

    Either of these would make a suitable blix given enough treatment time, but the first, if it worked, would be slow, and both methods would yield a very unstable blix. The second would be fast but very expensive.

    Lets now look at C-41. Bleach III is at working strength as-is, so that adding hypo solution only dilutes it further and weakens it. The same arguments hold as above regarding stability. The blix would decompose rather quickly. So, you cannot make a good blix from C-41 chemistry as it exists. You need to reformulate and can’t use Bleach III.

    Powder kits made with sodium salts of the ingredients is possible, but these become very slow acting. Remember that sodium based fix solutions are not “rapid fix” solutions. You have to go to ammonium based fix solutions to have a rapid fix!

    So, here is a quick rundown of the above:

    Use solid powders and the blix is too slow.

    Mix the bleach and fix parts normally then mix together, and the kit becomes weaker and less stable due to dilution. It also requires more time due to the loss in strength and you end up right back where you were with a bleach and fix situation. Mix the two parts without dilution if possible and the blix is fine for rate but much less stable. It becomes a one-shot essentially.

    In the end, you have about equal costs or more with a blix due to the shorter shelf life after mixing and the lower capacity.

    With a bleach-fix, the process is a tad more complex but not necessarily longer.

    With a blix, there is a chance to have silver retention with some film / blix combinations. This is due to the heavy silver load, the type of silver developed, and certain inhibitors used in color films to control image quality. The dyes also act to protect the silver from the bleach and so the dye cloud must be rendered penetrable by the blix.



    There are ways to limit any problems with blix kits.

    Use a long blix time! Use 2x – 4x the suggested time or more. It will not hurt. It does make the process longer.

    Mix the two parts right before use and in the quantity you are going to use. Don’t re-use it. But, this increases cost.


    There is a summary of some of my work over a 30+ year period on bleaches and fixes. The Bleaches and Blixes included Copper, Cobalt, Iron and various organic oxidants in order to optimize Blixes for films.

    As Ray said above, the problems with Blixes used with films were known years ago.

    Best wishes to you all, and whatever you choose, may it work well for you.

    PE

  3. #43

    Join Date
    Jun 2004
    Location
    South Norfolk, United Kingdom
    Shooter
    Multi Format
    Posts
    2,918
    Images
    66
    2. Ammonium Thiosulfate only comes as a liquid of about 60% concentration or about 600 g
    PE,

    I can apparently (I've not done so) buy Ammonium Thiosulphate from Silverprint here in the UK as 500g dry, I'm not sure about the format.

    Tom

  4. #44
    Photo Engineer's Avatar
    Join Date
    Apr 2005
    Location
    Rochester, NY
    Shooter
    Multi Format
    Posts
    23,544
    Images
    65
    Tom;

    That is essentially a typo. The liquids come as stated. No other liquid concentrations are available. No solid Ammonium Ferric EDTA is available. Solid Ammonium Thiosulfate is available but it is very hygroscopic (absorbs water from the air quickly) and it goes bad fast. It is also very expensive.

    Sorry for the lack of clarity. I hope my expansion on that line helps. Thanks for pointing it out to me.

    PE

  5. #45

    Join Date
    Jun 2004
    Location
    South Norfolk, United Kingdom
    Shooter
    Multi Format
    Posts
    2,918
    Images
    66
    Quote Originally Posted by Photo Engineer View Post
    Tom;

    That is essentially a typo. The liquids come as stated. No other liquid concentrations are available. No solid Ammonium Ferric EDTA is available. Solid Ammonium Thiosulfate is available but it is very hygroscopic (absorbs water from the air quickly) and it goes bad fast. It is also very expensive.

    Sorry for the lack of clarity. I hope my expansion on that line helps. Thanks for pointing it out to me.

    PE
    Thanks for clearing that up. Silverprint's price is 5.05 GBP per 500g.

    Tom

  6. #46
    Ian Grant's Avatar
    Join Date
    Aug 2004
    Location
    West Midlands, UK, and Turkey
    Shooter
    Multi Format
    Posts
    16,435
    Images
    148
    Quote Originally Posted by Photo Engineer View Post
    I cannot comment on the POV expressed by Ian, as I know nothing of it for all practical purposes.

    In the subject of bleach then fix vs blixes, I rely on the backing of 6 companies mentioned above for their agreement in this area. The big companies don't make a blix for any film even though it is possible.
    My POV is mainly as a user of various colour chemistry kits at an amateur and professional level from around 1969/70 onwards. I began making colour prints from C-22 negatives using the Pavelle process, and then shortly after Ferrania transparencies with a kit. Both processes were very finicky temperature control was critical and they were long winded.

    Around 1972 I began E4 processing, the kits were almost always actually "E3" as E4 was a bit toxic for home use. Very nice & easy to use.

    When E6 & C41 where introduced I obviously switched to the modern - current processes. Initially I used "liquid" kits from Barfen a small UK company, they also sold Fuji film in 30m/100ft. These kits used a bleach and temperate fixer.

    When Photocolor released the two bath Photocolor II C41 kit in 1976 there was a lot of scepticism because of the use of a Bleach-Fix (blix) and UK magazines, amateur, professional & trade, did exhaustive tests expecting there to be problems with silver retention but the blix past their tests. (By this point I'd begun working as a photochemist).

    Based on the reports I began using the new Photocolor products, I'm not sure when their Chrome 6 kit was released but I switched as soon as it appeared. They were exceptionally good, and the only time I had a problem was when I deliberately tried to exceed the Blix capacity, this showed up as soon as I made a print, unexpected grain (XP-2) it was barely visible looking at the negative, a re-blix and problem gone,

    I was only processing some of our company's C41 & E6, 75% went to a lab in a nearby city, but there were no differences in quality between films and subsequent prints using the Photocolor kits or the Fuji Q-lab.

    However I don't disagree with Ron (PE) about the problems of Blix's, every time other kits (using them) were tested in UK magazines they were found to fall short because of the Blix. I think even back around 1976 most UK colour photographers were careful to ensure that the Blix was complete and gave a bit longer time than recommended. I tried a Paterson 2NC kit once but didn't trust the blix, the Photocolor Blix acted very quickly indeed, but the Paterson blix didn't (years later the 2 companies merged).

    Photocolor dominated the UK market, I'd guess they outsold competitors products by about 10:1, I knew a lot of photographers using both the C41 & E6 kits and the print kits and no-one of them had quality problems, many had tried other low volume kits and had found them lacking. There were also some smaller labs using the 5 litre kits.

    The other company who I began using for RA-4 chemistry is Tetenal, it's more economic as I use the mini-lab packs, Their range of chemistry is exceptionally good and there's no problems with the Blix's they use in their C41 and E6 kits.


    Quote Originally Posted by Photo Engineer View Post
    The big companies don't make a blix for any film even though it is possible.
    I think that sums it up very well. Mason (& Levenson) re-wrote (1972) the Bleach-Fix section of "Photographic Processing Chemistry - 2nd Ed" to include work that Ilford and Agfa had done and patented, and referenced 2 articles Levenson had written about Blix's, concluding that reliable Blix's for films were no possible. (Mason - Ilford Research, Levenson - Kodak Harrow Research, UK).

    That's 4 years before Photocolor and they say it can be done But it's not efficient enough for a replenishment system due to the high silver levels in films and the blix is much more complex than a simple bleach & fixer so costs far more in comparison.

    Profit margins on kit's are significantly higher, chemical usage is small batch using chemistry up to 3 times so using a blix is more practical.

    Quote Originally Posted by Photo Engineer View Post
    The data comparisons appear to be absent in the patent. I just skimmed it though. The data I read over says that the blixes that were not of the invention took 2x or more of the time to clear the film of silver and silver halide than the blixes of the invention. I would have to review the patent in more detail.

    I can go on to say that the data was obtained, and was derived from x-ray fluorescence of silver retention and analysis of photomicrographs. If it were not available, the patent would not have issued.
    PE
    I wonder if the "tolerances" have been lowered in recent years, as modern C41 (and RA-4) processors are wash-less and there must be a trace of residual silver left in the emulsion.

    Finally from my POV there have been no problems with the kits using Blix's that I've used.

    I think Ron's warnings are very valid, I just caution against warning not to use a certain product, it's safer to recommend something you have personal experience of. Photocolor went when Champion moved manufacture from the UK to Spain, and got the contract to manufacture Kodak chemistry.

    So now all I'd personally recommend is Tetenal C41 & E6 kits. Because of the issues Ron raises and I share I wouldn't suggest anything I haven't tried although they might be equally as good.

    Ian

  7. #47

    Join Date
    Jun 2004
    Location
    South Norfolk, United Kingdom
    Shooter
    Multi Format
    Posts
    2,918
    Images
    66
    Quote Originally Posted by Ian Grant View Post

    I wonder if the "tolerances" have been lowered in recent years, as modern C41 (and RA-4) processors are wash-less and there must be a trace of residual silver left in the emulsion.
    I presume this is in reference to commercial mass-processing lab type environments? My Jobo (C-41), and Thermaphot (RA-4 / B&W) processors both incorporate water washes.

    Quote Originally Posted by Ian Grant View Post
    So now all I'd personally recommend is Tetenal C41 & E6 kits. Because of the issues Ron raises and I share I wouldn't suggest anything I haven't tried although they might be equally as good.

    Ian
    In the UK market the Fuji and Kodak kits are competitive or cheaper compared to the Tetenal colour kits.


    Tom

  8. #48
    Ian Grant's Avatar
    Join Date
    Aug 2004
    Location
    West Midlands, UK, and Turkey
    Shooter
    Multi Format
    Posts
    16,435
    Images
    148
    Quote Originally Posted by Tom Kershaw View Post
    I presume this is in reference to commercial mass-processing lab type environments? My Jobo (C-41), and Thermaphot (RA-4 / B&W) processors both incorporate water washes.

    In the UK market the Fuji and Kodak kits are competitive or cheaper compared to the Tetenal colour kits.

    Tom
    Even pro-Labs often use Minilab equipment for 35mm & 120.

    Yes the Kodak & Fuji kits are more competitive now, because the £ has slipped a lot against the Euro the Tetenal kits anren't a cheap as they used to be.

    Ian

  9. #49
    Photo Engineer's Avatar
    Join Date
    Apr 2005
    Location
    Rochester, NY
    Shooter
    Multi Format
    Posts
    23,544
    Images
    65
    I am not aware that RA-4 processes are washless. I'll have to check.

    I do know that C-41 can be washless but only using the C-41 Flexicolor RA Bleach and Fix. They have been modified to prevent problems with any possible retained silver complexes. In addition, the Final Rinse RA III must be used with this washless process.

    If you don't use the proper chemistry, you can end up with unstable negatives.

    You can use the RA chemistry with a wash however, with no problems.

    PE

  10. #50

    Join Date
    Jul 2006
    Shooter
    35mm
    Posts
    55
    I do appreciate all the posts in this thread. A very interesting read to say the least!

    Jack

Page 5 of 6 FirstFirst 123456 LastLast


 

APUG PARTNERS EQUALLY FUNDING OUR COMMUNITY:



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