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
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.
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.
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!
Here is Kodak's Publication J24 on HC-110 which shows how to achieve any dilution of working solution, whether from concentrate or stock: