mixing and storing, part 2

[jameshaskins]

hey everyone,

 

been reading about mixing and storage of chemicals and got confused. quick question.

tell me if im right or wrong here..

 

D-76; full strength (or stock) solution is when you dilute the WHOLE package with 3,8 lt of water. This stock solution

will last around 6 months in tight closed bottles.

 

1:1; is when you take the full strength (stock) solution of 3,8 lt and you add another 3,8 lt of water. therefore you

have 7,6 lt of 1:1 solution (working solution????). This solution can be used only once.

 

 

 

Dektol; full strength (stock) is the whole package diluted with 3,8lt of water.

 

1:2, is the stock solution PLUS 2x3,8 lt. so its 3,8lt of stock plus 7,6 lts of water to get the working solution.

THEREFORE its 11,4 lts of working solution.

 

IS THIS CORRECT?? these 1:1 and 1:2's and working solution, stock bla bla just gets me confused.....

 

 

 

thanks for your help,

 

James

[wclark5179]

Mix the chemical into stock sokution quantity. I use empty soda bottles as I find they work well for me. I'm still using

film developer that I mixed into stock solution in February 2006. What I do is write the name of the chemical like D-76,

the date I mixed it on masking tape then put it on the bottle.

 

The life of stock solution is determined by a couple of factors. I use bottled water to mix the stock as I find impurities in

regular water can hasten the life of the stock solution. I store the bottles of stock solution in a cool dark area,

underneath the sink! Having full bottles versus not full I've found doesn't really have much of an effect. If it did why can

I still use stock solution I mixed in February 2006 in September 2008? I use 2 liter soda bottles and the caps seal the

containers and the plastic doesn't seem to react with the chemicals. I thought I would share with you my experiences.

 

Once you have your stock solution then dilute it down for each roll of film you develop. If it's 1:1 then 1/2 of the amount

is stock solution then the other 1/2 is water. As an example if you were going to develop a roll of 120 film and the tank

was 16 ounces, then 8 ounces of stock plus 8 ounces of water measured in a beaker would be required.

 

Keep the stock solution as stock. Dilute it each time you use it.

 

Hope this helps you.

[Vlad Soare]

That's correct, James. You've got the dilutions right. I don't know about storage properties though, as I don't use D76.

[jameshaskins]

thanks guys, i thought that with dektol 1:2 ratio (11,4 lt) was making a lot of solution.too much. but thats great! its still expensive but not THAT expensive i guess.

 

any other input would be great. ill be checking this thread for a while.

THANKS!

James

[btmuir]

James,

 

I would recommend mixing the stock solution and storing that rather than diluting into working solution and storing.

 

1 to 1 D-76 gives coarser grain so if you wait to dilute it you could try it straight and see if you like it that way.

 

Also if you dilute it to 1 to 1, make sure you use enough if you develop multiple rolls at one time. I forget how many ounces

you need per roll of straight D-76 so you will need twice the amount if it is diluted 1 to 1. You can get the specs from Kodaks

website.

[bgelfand]

Hi James,

 

Mix the stock solutions the way you described in your original post and store the stock solutions.

 

As William wrote, mix working solution only in the quantity need, then discard it after use. Working solutions are "one shot". For Dektol that means one printing session, not one print. You are correct, you will eventually end up with at total over 11 liters of Dektol from one package, however that will be over many printing sessions. I usually mix about 800ml of stock Dektol with 1600ml of water for my printing session. When I finish printing, I discard the Dektol working solution. Compared to the cost of the paper I use, the cost of Dektol is negligible.

 

Working solutions do not keep well, even in tightly closed bottles.

 

The same principle applies to D76. Mix working solution from stock solutions, as needed, and then discard the used working solution.

[paul_hoyt]

James,

 

Welcome to stock solution and dilutions. Usually stock solutions are more stable than their dilutions. That is why

most are dissolved to make a concentrated solution. The nomenclature for making dilutions is varied.

Photographers that have a chemistry background are trained that 1:1 is stock and 1:2 is equal parts stock and

water. Non "scientific" photographers see 1:1 as equal parts stock and water. To keep discussions on equal footing

it is best to use a + sign instead of the : sign, then everybody knows what is stock and what is water; 1+1 for equal

parts stock and water, and 1+2 for 1 part stock plus 2 parts water. You will notice most photographic chemical

suppliers now use the + sign when they give suggestions for diluting of their liquid concentrates.

 

Paul

[michael_best2]

James, while I agree with most of what I read above, I will share some slight disagreement in regards to storing working

solutions. As my printing sessions may be anything from 1 hour to 4 or 5 hours, if I discarded working solution Dektol

from my 16x20 tray with each session, I would be discarding quite a bit of barely used chemistry. I use the often-vilified

accordion air evacuation bottles, have for years. Yes, you must use them carefully. Don't know how long these bottles

last, were purchased about 4 years ago from freestyle photo, don't see signs of deterioration. Once in a while, I won't get

the cap sealed perfectly and will wind up with air in that bottle. Generally, I find this out within a day or two, no big

problem. As to storage of working stock D76, I agree, don't do it, mostly. It is only when I get down to the last part of my

stock solution that I will dilute to working solution for storage because the air in a partially filled bottle is more deleterious

than storing the diluted chemistry. I have a hard time seeing chemistry being sensitive to dilution rate if it is not reactive

to the other ingredients in the solution. Air in the storage bottle is the much larger issue.

[wclark5179]

I only use the working solution of film developer once. Stop bath I do keep and fixer I rotate as I used a two bath fixing

system.

 

For print developer I would keep it in the tray for, at most, one day then I got rid of it. Sometimes I would make only one

print and I would throw the developer, stop bath and fixer away.

 

My clients deserved the best and I wouldn't try to save a few pennies from storing working solutions.

 

Since I'm 100% digital now I have very little time to use my analog equipment anymore. I will bring a film camera to a

gig, thinking I will use it but it rarely happens anymore. Sorry to say this on the film forum but I have to be truthful to

you.