Measuring your own Chem - D76 Bulk Buy

tommy5c · Aug 19, 2007

Ok so here's the story. I just bought a whole lot of darkroom stuff out of denver, Included in this buy was a lot of dry chemicals. the largest box of chem was a 9lb box of D-76. obviously i don't wanna mix all of it at once, i couldn't use it all before it went bad. so the nut of my question is I've figured that to mix dry D-76 at a liter at a time the ratio would be 104.675g of D-76 per liter. I want to know if anyone else has had experience doing this and if my math is correct. I'm pretty confident in my math, but i've only relied on pre-measured chems on the past. any comments or precautions?

srs5694 · Aug 19, 2007

The advice I've seen is generally to not mix part of a package of dry chemicals. The problem is that the component chemicals can separate out, leaving you with more of Item A and less of Item B in the first batch and vice-versa for the next batch. This can affect consistency of results.

If you've got local friends or neighbors who are photographers, you might try mixing up the whole lot and then splitting the mixed developer amongst you. That'll be safer and will also minimize waste.

If this isn't an option and you're determined to mix it up in small parts, your best bet is to thoroughly mix the dry chemicals before you mix each smaller batch. I'm not sure what sort of procedure would be most likely to produce good mixture, though -- shaking it in a sealed container, stirring it, etc.

glbeas · Aug 19, 2007

Most will tell you not to do it. Problem with the bulk is the powders don't mix evenly so you have some of the heavier ingredients trying to settle in it's own layer and so on. That said make sure the whole thing is stirred up real well before breaking it into fractions, the bigger chunks the better. One other thing you may well encounter is once the bag is opened even the dry powders will go bad at some point unless you can remove all the O2. I had this problem with a 5lb box of Dektol, the last portion had turned dark and once mixed had lost it's punch. Don't expect total consistency from your batches.

Photo Engineer · Aug 19, 2007

Do NOT under any circumstances mix part of a dry kit. The particles are non-uniform mixtures of several chemicals.

PE

tommy5c · Aug 19, 2007

it sounds like i have a 9lb box of D-76 for sale. i won't be able to mix and use all 39 liters at the same time. well i'm glad i ask. i wasn't sure with a premix like D-76. I'm not a big user of D-76 but i thought at that size it would last me a year or more. thanks for the advice and knowledge.

PhotoSmith · Aug 19, 2007

You could use this an excuse to crank up the volume of your shooting!??

tommy5c · Aug 19, 2007

PhotoSmith said:
You could use this an excuse to crank up the volume of your shooting!??

Unfortunately I'm trying to slow down and be more purposeful with my shooting. I thought the same thing- if i shoot 10 sheets a day, and tray develop each. i think that i might be able to use all 39 liters in the life span of 4 to 6mo. I do wish i had others around me that i could share it with, as of yet i haven't found anyone.

PhotoSmith · Aug 19, 2007

tommy5c said:
Unfortunately I'm trying to slow down and be more purposeful with my shooting. I thought the same thing- if i shoot 10 sheets a day, and tray develop each. i think that i might be able to use all 39 liters in the life span of 4 to 6mo. I do wish i had others around me that i could share it with, as of yet i haven't found anyone.

39 liters is a lot of developer! Just think of the capacity if you use it 1:1. It sounds like the best bet is to find someone to take it off of your hands.

There are a few rental darkroom facilities in Denver that might be interested if you check with them.

Good luck.

Dave Wooten · Aug 19, 2007

maybe one of the local college or high school programs could use it?

dancqu · Aug 19, 2007

Dave Wooten said:
Maybe one of the local college or high
school programs could use it?

Good suggestion. Another: add some sodium carbonate,
washing soda, and make a print developer of it. D-76 will
make a print developer very similar to Dektol. All it lacks is
the speed. Carbonating will give the 2 to 3 minute times
expected of a print developer. A 1/2 ounce, 15 grams,
per liter undiluted should do. Use full strength. I'd
dilute but that's another story. Dan

Photo Engineer · Aug 19, 2007

Dan;

The high sulfite level can cause speed losses with today's high chloride papers. I've tried it.

PE

Measuring your own Chem - D76 Bulk Buy

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