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HC-110 Dilution Question

  1. Randall R Bresee
    I have a question for experienced black & white film photographers.

    I have used 4x5 TriX film developed in HC-110 (B) for decades. Since HC-110 is now packaged only in larger quantities, I decided to change my basic procedure for preparing working developer. I used to prepare stock solution from the concentrate and then made dilution (B) working developer as needed from stock solution. That was okay since HC-110 concentrate could be purchased in small quantities (16 oz). Now that concentrate is available only in larger quantities, I plan to prepare dilution (B) working developer as needed directly from the concentrate (the "one-shot" procedure) since shelf life of concentrate is significantly longer than the stock solution.

    That sounds reasonable but then I looked at the numbers.

    The Kodak Technical Data Sheet for HC-110 says that the one-shot procedure for dilution (B) working developer requires diluting concentrate with water at a ratio of 1:31.

    I calculated that the ratio is 1:28 when the concentrate is diluted 1:3 to prepare stock solution and then stock solution is diluted 1:7 to make dilution (B) working developer. That is, 1 oz concentrate is diluted with 3 oz water to make 4 oz of stock solution. Then, 1 oz of stock solution (which contains 1/4 oz concentrate) is diluted with 7 parts water to make dilution (B) working developer. The overall ratio is 1/4 : 7 which is equivalent to 1:28.

    The dilution difference between 1:31 and 1:28 is large enough to be of concern. Am I making a calculation error?

    Randall R Bresee
  2. MAMIYA645
    MAMIYA645
    Hi
    I have been using 110 for a while now so to produce 1 ltr of B dilution the calc is 1000/32 = 31ml of dev and 969 of Water
    You can use this as low as mixing 500ml which is fine for one 110 film or in fact 300ml for one x 35ml film
    In each case the dilution is 1:31 = 32 actual parts, so the volume of 110 to water is always the total final required develper divided by 32
    300ml is therefor 300/32 = 9ml. Therefore develper at 31:1 = 9.375ml dev to 291 water.
    I have experimented using the finished S.G (Specific gravity) and using 9ml works well and is well within the 1.008+/- 0.003 at 1.007. You can use 10ml but this then gets near to the A dilution rate.
    As the neat HC110 lasts for so long, I generally use it as a one shot to maintain quality of result in relation to graining and shrpness etc.
    Hope this calculation explanation helps.
    Regards
    Don (England)
  3. Mark_S
    Mark_S
    Randall

    I also use 110, and dilution B, which I do straight from concentrate, and use it one shot. I use a syringe to measure the concentrate.
    I think that it comes out the same if you mix from stock: if I wanted to make 32 oz of developer from the concentrate, I would mix one ounce of concentrate with 31 oz of developer - easy. If I wanted to make 32oz from stock, I would mix 4 oz of stock with 28 oz of water (1:7 ratio), and to get the 4oz of stock, I would mix 1oz concentrate with 3 oz of water. So either way, I am putting 1oz of concentrate into the mix.

    An alternative to HC-110 that still comes in smaller size bottles is Ilfotec-HC.

    Mark
  4. Randall R Bresee
    Randall R Bresee
    Thank you for your responses. I see the error in my computation now. I'm glad it is settled so there is one less thing to worry about!
  5. silveror0
    silveror0
    Here is Kodak's Publication J24 on HC-110 which shows how to achieve any dilution of working solution, whether from concentrate or stock:

    http://www.kodak.com/global/en/profe...bs/j24/j24.pdf
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