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  1. #1

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    B.Thornton 2 bath film dev - testing

    Hallo all,

    A couple of weeks ago I asked some questions about 2 bath film developers and got some very useful replies from you folks. Well, of marginal interest to all but I got the raw chemicals and mixed up the baths for Barry Thornton's 2 bath film developer - but would it work?

    Longish story short but I processed the second test film tonight and it looks acceptable! I shot two scenes at bracketed exposures and see images of varying densities and the film edges look good density. My first time mixing up a formula from self-measured chems rather than pre-packaged chems so pleased to get something looking reasonable especially as the first test film came out really really thin - I think my mistake was to pre-soak the FP4 before the dev, I didn't want to "spoil" the first bath with the dye off the film. The film was really thin, so perhaps not a good idea!

    Stupid me for adding a variable into testing a developer but hey ho. Going to try some prints over the weekend & high hopes to getting something interesting out of the exercise. Again, thanks for the feedback on my initial question/post.

    Sim2.

  2. #2
    Harry Lime's Avatar
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    Yep, you want to skip the pre-soak

  3. #3
    ParkerSmithPhoto's Avatar
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    Just mixed up my first batch tonight. 12 rolls to soup over the weekend!
    Parker Smith Photography, Inc.
    Atlanta, GA

    Commercial & Fine Art Photography
    Portrait Photography

  4. #4
    David Allen's Avatar
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    Hi there,

    I have been exclusively using two-bath developers for more than a decade and BTTB developer for the past 5 years. I always pre-soak my film and achieve consistently good results. In fact all of the photographs on my website were made using Delta 400 exposed at an EI of 200 and developed in two-bath developer (with BTTB I use 5.5 minutes in each bath). The real key to testing a film/developer combination is to use a consistent and repeatable system. I recently answered a PM with the following system that I have taught for many years:

    Now the key to achieving consistently good negatives is the correct placement of your shadows when exposing the film and ascertaining the correct development time for achieving good separation without losing the highlights. A simple and relatively quick way to way to pin all this down for the future is to do the following (WARNING: reading these instructions is more time consuming and a lot more laborious than actually doing it!!):

    1. Find a scene with with a good range of tones
    2. Using the box speed, meter the darkest area in which you wish to retain shadow detail
    3. Move the camera so that you are only photographing this shadow area
    4. From the meter's reading close down the aperture by 2 stops or increase the shutter speed by two stops and then expose 6 frames at: the given exposure then +1 stop, +2 stops, -1 stop, -2 stops and -3 stops less than the meter has indicated

    5. Process the film

    6. Using the frame that was exposed at -3 stops less than the meter indicated (which should be practically clear but will have received lens flair and fogging - i.e a real world maximum black rather than an exposed piece of film that has processing fog) and do a test strip to find out what is the minimum exposure to achieve maximum black - Print must be fully dry before assessing this
    7. Do another test strip with the first exposure being what you have selected for achieving maximum black minus your dry-down compensation then plus 1 second, 2 seconds, etc
    8. The time that achieves full black inclusive of compensation for dry-down is you minimum exposure to achieve maximum black for all future printing sessions - print must be fully dry before assessing
    9 You now know the minimum time to achieve full black inclusive of exposure reduction to accommodate dry-down
    10. Using this minimum exposure to achieve maximum black exposure time, expose all of the other test frames.
    11. The test print that has good shadow detail indicates which exposure will render good shadow detail and achieve maximum black and provides you with your personal EI for the tested film/developer combination

    12 If the negative exposed at the meter reading gives good shadows, your EI is (when metering shadows where you wish to retain good detail) the box speed (i.e. for 400 film you need to set your meter at 400)
    13. If the negative exposed at +1 stop more than the meter reading gives good shadows, your EI is (when metering shadows where you wish to retain good detail) 1/2 the box speed (i.e. for 400 film you need to set your meter at 200)
    14. If the negative exposed at +2 stops more than the meter reading gives good shadows, you EI is (when metering shadows where you wish to retain good detail) 1/4 box speed (i.e. for 400 film you need to set your meter at 100)
    15. If the negative exposed at -1 stop less than the meter reading gives good shadows, you EI is (when metering shadows where you wish to retain good detail) double the box speed (i.e. for 400 film you need to set your meter at 800)
    16. If the negative exposed at -2 stop less than the meter reading gives good shadows, you EI is (when metering shadows where you wish to retain good detail) 4x the box speed (i.e. for 400 film you need to set your meter at 1600)

    You have now fixed your personal EI but there is one more testing stage to go.

    1. Find a scene with with a good range of tones
    2. Using your EI, meter the brightest area in which you wish to retain highlight detail
    3. Move the camera so that you are only photographing this highlight area
    4. From the meter's reading open up the aperture by 3 stops or decrease the shutter speed by three stops
    5. Expose the whole roll at this setting
    6. In the darkroom, process one third of the film for recommended development time

    7. When dry put negative in the enlarger and make a three section test strip exposing for half the minimum black time established earlier, for the established minimum black time and for double the minimum black time.
    8. Process print and dry it.
    9. If the section of the test strip exposed for 1/2 the minimum black time gives bright highlights with a trace of detail then the film requires 20% more development
    10. If the section of the test strip exposed for the minimum black time gives bright highlights with a trace of detail then the film is correctly developed
    11. If the section of the test strip exposed for double the minimum black time gives bright highlights with a trace of detail then the film requires 20% less development
    12. You can use the rest of the exposed highlight test film to fine tune the development time.

    YES - it is VERY boring but . . .for the investment of minimal materials and a few of hours you will have pinned down so many variables that it is really worth doing.

    Back in the real world, all you need to do in future is meter the shadows that you wish to retain good detail with meter set at your EI and then stop down the aperture 2 stops or increase the shutter speed by 2 stops. In the darkroom start your first test print with the minimum exposure to achieve maximum black (inclusive of dry-down compensation) and go from there.

    Hope this is of some help and best of luck with BTTB developer.

    David
    www.dsallen.de

  5. #5

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    Hallo again,

    Just to let you know that the second test film worked better - why did I pre-soak the first one when I know that Ilford say not to pre-soak FP4? Hey ho, these are the decisions we make! Anyway, no pre-soak on the film and when I emptied the first bath back into the container there was not the expected dye stain in the chems, it was the same colour as it went in, so all good from that point of view. But got me thinking about the "coloured dye" - but I digress.

    The film... a lot softer in contrast than what I am used to. Although I did not have the exact same image dev'd through my normal ID11, which was the intention with test 1, the lighting was controlled and I had an expectation of what to expect. A lot softer contrast than to be expected with ID11 and was very different to print as I know that I do tend to process for a "punchy" neg - normally printing at between grade 1 to 2, with these test negs a straight print went through at around grade 3 to 3.5. Having done similar test with ID11 I know that to get a straight print needed a -2 dev but that overly compressed the mid-tones. With the BT2B the straight print at a harder grade than I would normally expect kept detail in the deep blacks, held on to the extreme highlights and with a good separation within the midtones. Quite an interesting result really as the result was pretty much what has been said about 2-bath devs and gave a result on the neg that is the total opposite of my experience with -2 "zone" style development.

    I am thinking that this will be a useful extra tool to call upon when circumstances suit. All told - good times.

    Sim2.

  6. #6
    David Allen's Avatar
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    Glad to hear that you are getting to grips with BTTB developer and liking it.

    One point that I made in my earlier post is that the pre-soak was not your problem. I always pre-soak my films. When a friend or colleague contacts me about processing marks (usually with 35mm film) I always recommend pre-soaking and it always solves the problem.

    Best,

    David
    www.dsallen.de

  7. #7
    Harry Lime's Avatar
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    Here are some examples of my work with BT2B.

    Click here for pictures

    All the daylight shots are Tri-X done in BT2B.

    The night shots are a mixture of Tri-X, TMY-2 400, Delta3200 and TMZ3200P. Mostly developed in Diafine, but the Kodak P3200 was done in Tmax developer.

    There is more on the main website. The New Orleans work is Tri-X in DD-X, but that is a long time ago.

  8. #8

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    Never mind the developer - you have a good eye and a nice sense of humour.

    Looks like it is working for you. I use it with Delta 400 (roll) and Delta 100 (sheet) and it seems to be doing the job.
    I feel, therefore I photograph.

  9. #9
    Harry Lime's Avatar
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    Thank you.

  10. #10
    ParkerSmithPhoto's Avatar
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    Quote Originally Posted by Harry Lime View Post
    Thank you.
    Great stuff, Harry. There are some really tremendous images there. The "coat sale," people near the bridge and the park are 3 of my favorites.
    Parker Smith Photography, Inc.
    Atlanta, GA

    Commercial & Fine Art Photography
    Portrait Photography

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