Partial batches of D-76, Stopbath, Fixer, Dektol

[laura_d1]

<p>So, I'm setting my my first darkroom on my own and I mistakenly bought larger packs of chemistry than I realized I would need. I read several posts about it for D-76 and people seemed to agree that you needed to mix the 1:1 stock solution no matter what. Assuming I can measure out the powders with a fair amount of accuracy, are there any problems due to exposure of powders to air?<br>

This is for D-76, Dektol, Stopbath, and Fixer.<br>

Also, if I decide to mix the larger batches, I was confused about how D-76 and Fixer 'make one gallon'. Is it that you add one gallon to the powder (yielding slightly more than 1 gal) or do you put the powder in a one gallon container and fill it with water until it's full?<br>

Thanks!</p>

[thirteenthumbs]

<p>The packages should have mixing instructions printed on them.<br>

D76 and Fixer start with 3 quarts water at 75°F - 80°F, and with constant stirring, slowly add the contents of the package. Stir until the powder is fully dissolved. Add water to bring the total volume to amount the package is for.<br>

<br />Mix the entire package of powder, do not split it as the various component chemicals are not dispersed evenly except for the entire package.</p>

<p>Let the mixed chemicals sit for 12 to 24 hours before the 1st use. <br>

Do not dilute the D76 further until ready to use then discard after 1 use. See Kodak tech pub J78: http://www.kodak.com/global/en/professional/support/techPubs/j78/j78.pdf</p>

[Mike Gammill]

<p>If you want to split up the chemicals it's far safer to mix the full stock solution and then decant it into small glass bottles. You can extend the shelf life with developer this way. Not so critical with fixer as use will exhaust it rather than oxidation like developer. </p>

[User_5888660]

<p>The package says D-76 should be mixed using 122-131 f degree water. </p>

[john_shriver]

<p>There's <strong>no requirement</strong> to use D-76 with further dilution to 1:1. It is useful if you want coarser hard-edged film grain, and a slightly different tonal curve. It doesn't save developer if you follow Kodak's instructions, since you have to use 8oz of D-76 and 8oz of water for one roll of 35mm film. (If you use 4oz and 4oz, you have to increase the developing time.)<br>

If you do dilute to 1:1, this should be done immediately before processing, and you must use the 1:1 solution one shot (use and throw out).<br>

Keeping D-76 in totally full 8oz or 16oz glass bottles will increase shelf-life a lot.<br>

If you're at the point where you think one gallon of D-76 is "too much developer", look into using liquid concentrate developers that you mix one-shot. That would include Kodak HC-110 (mix directly from syrup, no stock solution), Ilford Ilfotec DD-X, and Ilford Ilfosol 3.</p>

[Monophoto]

<p>While you may be able to measure dry powders quite accurately, you cannot assume that the powder is homogenious, it, that the components are uniformly blended. So mixing partial batches from dry powders is not recommended.</p>

<p>You can certainly mix partial batches from liquid concentrates. In fact, that's a good reason for buying chemicals as liquid concentrates rather than dry powders. D76 and Dektol are only packaged as powders - you can mix a 'stock' solution (a concentrate) that you store in a sealed bottle, and then mix smaller quantities of a working solution as needed.</p>

<p>The advantage of dry powders is that you aren't paying for water, and they are easier to ship, which means that the shipping cost will be lower. So it's a matter of balancing the higher cost of liquid concentrates against the greater convenience of working with liquids. Another factor is that it's not possible to work with powders without releasing some dust into the atmosphere - that dust will contaminate any darkroom surfaces that it falls on, and you really need breathing protection when it's in the air. I started out with powders, but eventually realized that it makes more sense for me to use liquids.</p>

 

[cj8281]

<p>Upon opening the packages you should note the color of the powder, it should be white. If it looks the color of Cocoa Cola then it is oxidized in the packaging. When oxidized it looks like this: <a href=" </a><br>

This was from a pinhole in the corner of the bag, can you imagine how long it would last if it was opened to the air and not sealed? This is true for Dektol and D-76. <br>

I use my D-76 at 1:1 and as others have said, you mix it 1:1 from your stock solution right before you use it. I use it in an 8 ounce tank so that means I only use 4 ounces per roll. This means that I can develop 32 rolls of 35mm film with one gallon. If you use a tank that requires 375ml per 35mm roll of film, you will only get 20 rolls out of a gallon.<br>

Decanting the stock solution into smaller bottles filled to the top sounds like a good idea but I have found with my situation that I don't need to do that. I have used my stock solution that was over a year old without any issues but you need to watch it as it gets older, if it turns yellow then it is oxidizing. It may still work but it may not be consistent with previous results.</p>

<p>Stop bath seems to last a very long time, the stuff that I bought is a liquid and you only need 2 ounces of it to make a gallon. The concentrate has a very strong smell, do not sniff the open bottle. </p>

<p>The powdered fixer makes a gallon. Since you are setting up a darkroom, you will want to split this up. IIRC one gallon of fixer will fix 100 regular films (like Tri-X, HP5+) or 66 tabular films (like Delta 100, Tmax films). You will use up the fixer faster with prints and it is mixed 1:1 for paper. That means that it mixes one gallon for film and two gallons for paper. <br>

I would set aside 1 quart for film and leave the rest as stock solution. Reuse the 1 quart for your film until it is exhausted. You can keep track of the usage or you can test it. For paper I would mix only what you are going to use at the time you are printing. I would buy a bottle of Hypo Check and use that to determine if your print fixer is exhausted. I use white trays so I have a piece of black photo paper that I slip into the fixer and put 2 drops in the fixer above the paper so I can better see if it turns white or not. You can read about it here: <a href="http://www.freestylephoto.biz/69800-Arista-Premium-Hypo-Check-.75-oz.">http://www.freestylephoto.biz/69800-Arista-Premium-Hypo-Check-.75-oz.</a><br>

Now for film you can do a simple test using a piece of film. <br>

Pour about 2 ounces or so in a small clear container like a shot glass. Take a small piece of film, I use a piece about an inch long, and put a drop on the emulsion side of the film and start your timer. At 30 seconds drop the piece of film into the container and make sure it is submerged. Continue timing. When you can no longer see the original spot, the film is cleared. At this point note the amount of time it took. This is your baseline. Do this test periodically, more frequently near the end of its life, and keep notes of the time. When the time it takes to clear is double the original time (the baseline) then it is time to replace it. Use the same type of film for all the tests to keep it consistent, different films clear at different times. <br>

You can use this test to determine how long you need to fix your films also. Use a piece of the leader to do the test, for regular films you double the amount of time that it takes to clear and for tabular or delta grain films you triple the time. </p>

[cj8281]

<p>Here is a picture of my oxidized bag of Dektol. <br>

See the upper left corner of the bag, this is where the pinhole was. I tossed 9 bags of Dektol that day. If it remains sealed, it will last a very long time. This is what you want to look for when buying older chemistry, lesson learned. It cost me $9. </p><div></div>

[craig_shearman1]

<p>Don't drive yourself crazy trying to stretch out the life of a gallon of developer. I mix the full gallon and throw out what's not used by the time it goes bad. It's easily good for three months. I've sometimes used six-month-old developer without a problem. I use D-76 straight, no dilution, and it goes down the drain after each roll. At 8 ounces per roll, you get 16 rolls out of a gallon. If you average a roll a week, you can easily use up a gallon before it goes bad. If you shoot less and end up throwing some out, you've still come out ahead compared with the price of sending film out for developing. A gallon of developer is still around $10 or less depending on where you buy. Even when you add the cost of fix and stop bath you're looking at less than $2 a roll, maybe closer to $1 if you buy at a major supplier like B&H.</p>

[daniel_keating1]

<p>Here is what I do... Shake the powder in the bag--knead it or place in larger gallon ziplock and give it a tumble to blend it. I purchased a small digital "drug dealer" scale from amazon for about $7. I measure out 1.6 gr per oz of water for D76 (16gr for 10oz/300ml tank)--this factoring a 1:1 dilution. For a stock solution it's 3.2gr per oz of water. A gallon mix of fixer is 700grams and does 100 rolls. 7 grams per 300ml water for a one shot. Keep partial powder mixes in air-bled ziplocks.</p>

[daniel_keating1]

<p>PS to above post...here is a shot from my measured out powder</p><div></div>