Mixing D76 stock solutiongreenspun.com : LUSENET : B&W Photo - Film & Processing : One Thread
I just tried mixing up some D76 stock solution. Following the directions on the package, I added the powder to 800 ml of hot water ~125 F. After a good bit of stiring I managed to get the powder in suspension, forming a milky looking liquid. I poured this into my 1 gallon jug and added enough cold water to bring it up to 1 gallon. When I look into the jug after shaking it up a bit, I can still see some of undissolved granuals floating about.
If I let this sit a few days will all of the granuals dissolve? What is this stuff supposed to look like when ready for use? What, if anything, did I do wrong when I made up the solution? Should I pitch this batch and start over?
-- Peter Schauss (firstname.lastname@example.org), April 09, 2002
Did you use 1 quart pack or 1 gallon pack?
If you used a gallon pack, start with about 3 to 3.5 liters of water, dissolve everything, and adjust the final volume to 3.85 liter.
I don't know how hard it is to dissolve all powder of a gallon package into 800ml of water, but if everything clears up in a day or two, it should be fine. If you want to make sure, use a small piece of film (edges that are cut off from 35mm strips would be fine) to check if the developer is alive.
Stock D-76 should be a clear solution free of visible precipitation. At room temperature, whatever resisting to dissolve is probably metol or hydroquinone. Don't filter them out. Let it sit and dissolve.
If you can't stand this painful dissolving process, mix D-76 from scratch or use Ilford ID-11.
-- Ryuji Suzuki (email@example.com), April 09, 2002.
By coincidence, I just got finished mixing a quart of D76 a few minutes ago. I used water heated to about 140 degrees (F) and there were no solid particles floating around when I got through. Follow the directions for mixing by starting with a smaller amount of water than the final amount and pour the powder in slowly while continuously stirring. I'm unaware of any problem using water that is hotter than the 125 degrees (F) that is recommended. If using water hotter than that is contraindicated someone please let me know so I don't make that mistake again. Otherwise I think the key to dissolving all the powder right away is by using hotter water, pouring the powder slowly and stirring well. Good luck with your D76.
-- Dennis Couvillion (firstname.lastname@example.org), April 09, 2002.
My experience is that D-76 dissolves quickly at 110 degrees or so, except for a few suspended white particles, which will disappear soon.. Even with these particles visible, the liquid is perfectly usable. Solution is not complete, however, if granules still collect on the bottom of the container as soon as stirring stops. Solution can be accomplished at temperatures lower than the recommended 110 degrees, but it takes longer.
-- Keith Nichols (email@example.com), April 09, 2002.
Definitely something wrong here. If you had a 1 liter pack, then the 800 ml number is about right, and you now have watered down developer by making it up to a gallon. If you started with a 1 gallon pack, then 800 ml of water was way too little to start with. On the positive side, the stuff will probably eventually dissolve and work fine. Being lazy, I bought a surplus magnetic stirrer and just let the stuff mix for an hour or so. You don't want to introduce air by shaking developers!
-- Conrad Hoffman (firstname.lastname@example.org), April 09, 2002.
If you used tap water, I wouldn't worry. It could be that you have hard water, and these are just particles of water hardness that have been precipitated out by dissolving the D-76. The main component of D-76, Sodium Sulphite, can react with water hardness to form these insoluble granules. If they don't amount to more than about half-a-teaspoonful in the gallon, then just filter them out, or decant off the clear liquid. It'll be fine.
You could try changing to Ilford's ID-11, which has a water softening component incorporated.
-- Pete Andrews (email@example.com), April 10, 2002.
I have the same experience when mixing D-76 – Little particles that float around for a while, but if I let it sit for a day, then they disappear, and everything works fine.
I just bought a new gallon package of D-76, and there are new instructions. It does state to start with 800ml of hot water, which differs from the old instructions, which called for a larger amount to start with. I tried the smaller amount, and it worked fine. I am not sure why Kodak changed their instructions.
-- James Webb (firstname.lastname@example.org), April 10, 2002.
Slightly off your question topic, but I've had excellent results with lford's Ilfosol S, sometimes referred to as "D-76 in a bottle". Very economical (1+9 or 1+14), available in small quantities, great shelf life, and you dilute and mix only what you want to use. Results are very similar to D-76, if not a little better in my experience.
-- JM Woo (email@example.com), April 11, 2002.
Thanks for all of the encouraging words on mixing D76.
To answer a question which came up several times, I had the gallon size packet. Evidently it had the new instructions because it said to dissolve the contents in 800ml of hot water and then add enough water to make up one gallon.
In any event, after sitting overnight, the solution was clear so I used it to develop a role of HP5+ 120 which I was using to test out my "new" Yashica A. The negatives looked OK. I'll know more after I run a contact sheet and a few prints tonight.
-- Peter Schauss (firstname.lastname@example.org), April 11, 2002.
With D-76 type developers it is ok to begin with water temperature higher than recommended if your experience says it helps. However, they tend to recommend lowest usable temperature for dissolving chemicals so that you could use the solution without waiting too long to cool down to 20C. If you wait overnight to be absolutely sure anyway, then it doesn't matter much.
One exception is XTOL or anything that contains ascorbate because it decomposes easily at higher temperature. However, XTOL is easy to dissolve (no metol or hydroquinone) so you shouldn't need hot water anyway.
Metol is hard to dissolve in sulfite rich solution. Presence of base helps a bit, but Ilford ID-11 has metol and hydroquinone in a separate package to make it easy to dissolve. If you see no precipitation after dissolving part A but see something after dissolving B, that's probably borax, sulfite or inorganic minerals from tap water. This stuff, I wouldn't worry much about. But if you see something after A before B, I wound work hard to get them disappear (into water, of course). One problem with Kodak's D-76 package is that you can't tell what's in the precipitation... Well, you can see if it's particle or needle like and get some idea, but it's probably not worth worrying if you can byu ID-11 or mix your own D-76 (D-76H is simpler and just as good).
I don't know why Kodak changed the instruction... I bet my $0.05 on a hypothesis that Kodak let someone with no or little darkroom experience to revise package printing :-)
-- Ryuji Suzuki (email@example.com), April 11, 2002.
Something you might want to look into is purchasing an old hot plate with the magnetic stirrer function. I used to work in a biochemistry lab and my boss let me have an old one. Heat your water in a glass flask with a thermometer in it (or pour some hot water into any old container), put a magnetic stir bar inside and turn it on, and slowly add your powder. This completely dissolves all solute particles quickly, and you can leave the hot plate on at a constant temperature.
-- floren (firstname.lastname@example.org), April 15, 2002.