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  1. #1

    Join Date
    Dec 2004
    Milwaukee, Wi

    A fine B&W Proportional Reducer. RA4 Blix

    In the July/August 1992 issue of Darkroom & Creative Camera Techniques..now called Photo Techniques magazine is an article by Hans F. Dietrich who was a retired electron microscopy instructor who had authored and co-authored sveral papers on optical and photographic techniques.

    In the case present he wrote an article about using RA4 bleach fix as a proportional reducer. A proportional reducer can be most useful in correcting overdevelopment. To be considered a proportional reducer the reducer must remove film density in proportion to its existence. In other words those bullet proof highlights will receive more reduction than will the shadows. This has the effect of reducing contrast.

    Mr Dietrich indicated the the main problem he had experienced with proportional reducers was their unpredictable nature. Using the same film and reducer one time the reduction would be very slow and the next time the image would almost disappear before your eyes. This makes a proportional reducer rather useless.

    Mr Dietrich also worked at least as much with color chemistry as he did with b&W. Therefore he had ready access to color chemistry. He investigated RA4 blix with several different films. Among the films tried were Agfa APX25,
    Tmax 400, TMJAX P 3200.

    In every case the film and reducer worked in a consistent manner. Some film typesreduced quickly, others very slowly Which is to say that whether or not the reduction was slow or fast one could count on a dependable reduction rate. If you wished to slow down the rate of reduction you could dilute it with water. HE RECOMMENDS TESTING FOR FIRST USAGE OF A GIVEN FILM WITH A PURPOSELY OVER-DEVELOPED NEGATIVE. He recommends starting your initial test with a bleach/water ratio of 1:2.
    If you wish to accelerate the reduction rate because it takes too long he recommends prebathing the film in a liter of water into which has been added 10m/l of a 1/10th percent potassium iodide solution...the basic stock solution is 1 gram of potassium iodide diluted in a liter of water. You take 10m/l of this and add to a liter of water for your prebath. You pre-bathe for 1 minute. In some graphs he provided it shows the reduction rate of 400Tmax being increased by almost three times. He recommends a E6 Conditioner also as a another accelerrant for a 1 minute prebath.
    Finally for really speeding up the process he recommends adding to a liter of either a straight blix or diluted blix 1 gram of 5-amino-1,2,3-thiadiazole-2-thiol
    an ingredient in reversal print blix. As the negative is reduced the grain gets finer.

    So, big deal hey! What good is this stupid stuff anyway?

    Well, I found out how good it was. I had been visiting my son in San Diego. I came home with 7 rolls of 36x 100TMax. Having the capability of doing so I developed all seven rolls in one crack. The developer of choice at that time was Pat Gainer's original metol/ascorbic acid developer. I kept this in two stock solutions. I still use it 1:1 with water as a print developer. Trouble is I forgot to dilute my A&B mix with three parts water. To compound my felony I increased my development time by 10%.

    These were some very over developed negatives.VERY OVER DEVELOPED INDEED.
    I reduced all seven rolls in straight RA4 blix.


    It works wonderfully well.

    Thank You Hans whereever you are.

  2. #2
    Sean's Avatar
    Join Date
    Aug 2002
    New Zealand
    Multi Format
    Blog Entries
    comments from the previous article system:

    By pentaxuser - 07:22 PM, 08-28-2005 Rating: None
    More a questio than a comment. Would this work for individual negatives that have high contrast due to the light/shadows at time of the exposure? I have some negs which are very contrasty and almost unprintable without complex dodging but contained in a set of negs which includes others which are probably more contrasty than ideal but still printable. Specifically one neg is of two figures( my wife and a female friend in a beach shelter, one of whom is in total shadow and the other in bright sunlight. I had followed the film instructions on development time and while this was probably too long it was not disastrous except for this neg. In other words is this an alternative to contrast reduction masking which seems to be very involved by comparison and for which I probably lack the skill and equipment. RA4 blix sounds much more straightforward but would it work in my circumstances which wasn't overdevelopment as described in the article.

    Does the RA4 blix used retain its potency for re-use as RA4 blix or should the amount used be discarded. Presumably if it was only one or two negs then a small quantity only is required and small containers such as small ice-cream containers could be used. I take it the action of the blix is stopped by washingand the reduction is never fast enough to go too far before you can stop it?

    However if the reduction is overdone, is there a reversal process?

    If it resulted in soft prints but showing detail I would not be overly concerned about that as the principal viewer, my wife, seems to prefer prints which I suspect are soft by most APUG members standards.

    For what it is worth I believe that most of the public favour soft light prints with lots of shades of grey at the expense of brilliant whites and blacks. All the prints for sale in my local photography shop seem to be of this kind and clearly sell well.



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