Diluting Developer: Water into developer? Developer into water?

[RJMLuke]

I know when mixing caustic chemicals you add the chemical into the water. Is this the same with developers that need diluting(i.e. D76, TMax, Microdol-X, DK50, Acufine, etc) Thanks.

-R

 

[Kevin Caulfield]

If it has to be one way or the other, I would do it that way. Personally I add both developer and water to a third container.

 

[rwyoung]

Unless your developer is made from 100% lye or sodium hydroxide you can do it either way...

When I use Pyrocat and have to mix it down 1:1:100 or 2:2:100 depending on what I'm doing, I start out with about 85% of the final fluid volume, add my part A and part B in the appropriate amount then top off to the final fluid volume. Likewise mixing down Rodinal I start with a little water in the vessel, add the Rodinal then top off to the final volume.

When I used D76 more frequenly, it would be at 1:1 and I would just add in the stock D76 first and then add the water. Same goes for Dektol when diluting for the tray.

 

[Slixtiesix]

I simply follow the rule "Always do it as you oughta, put the acid to the water."
though I know that developer isn´t an acid and I don´t expect Perceptol to explode
if I´d do it the other way round. ;-)

 

[jim appleyard]

Yeah, caution is a good thing and by-the-book you should probably add the dev to the water. Having said how you *SHOULD* do it, I never have! (at least with something like D-76; as Mr. Six says, Perceptol won't explode on you.

Now playing with sod. hydroxide, etc., that's a different kettle of fish; always add the acid/base to the water.

 

[Bruce Osgood]

I thought you added the smaller amount into the larger amount.

 

[Stoo Batchelor]

When I use Pyrocat and have to mix it down 1:1:100 or 2:2:100 depending on what I'm doing, I start out with about 85% of the final fluid volume, add my part A and part B in the appropriate amount then top off to the final fluid volume.

Sorry, I do not mean to be pedantic, just to be clear, would you be as kind to explain this further. Only, I am a little bit confused as to why you don't just add the part 'A' and then the part 'B' of Pyrocat straight in to your final measure of water. The way you do it just seems to be an awful lot of messing about.


Regards

Stoo

 

[rwyoung]

It mixes things for me "automatically". And it is a hold over from mixing from raw chemical stock, ever seen the last step that says "water to make 1 litre".

And with Pyrocat in particular, I use a small graduated cylinder to measure things out, a 10ml glass one. Its inner diameter is so small that it never seems to pour out all the liquid inside. Return it to vertical and it reads out 0.5ml or there abouts, plus what sticks to the walls (thicker than water, perhaps it is photographic blood?). The volumes of part A and B when I'm developing only one or two rolls/4x5 in the Jobo is so small that this seems like it could be a significant error. So after adding part A to about 85% of my final volume of water I can fill the graduate a few times with distilled water and dump into my target container. This gets out all the "goodie". Then repeat after part B.

Example: 1:1:100 of Pyrocat and total volume of 250ml. So I need 2.5ml of A and 2.5ml of B and 245ml of H20. If 0.5ml of that 2.5ml is getting stuck in the graduate I'm going to be way off on the proportion. I could either pour out 3ml and hope that it is always 0.5ml that gets stuck or rinse the graduate into my solution. Rinsing out the small amount should keep my proportions consistent from batch to batch.

In the other cases it is all about minimizing the amount of washing and rinsing I have to do. I don't have a single decent measuring vessel that can fill 12x16 tray so I use a 500ml beaker. Pour in the Dektol, dump in tray, add 3 more beakers of water and I'm at 1+3 which is the usual dilution I use with Dektol. And my beaker is pretty darn clean because it has been rinsed three times with distilled water. Depending on the amount of printing I want to get done, 2000ml may not be enough in the tray so there might be a repeat performance at 125ml increments etc. Notice I used 1+3 and not 1:3.

In the greater scheme of things it doesn't matter much which way you do it so long as you always do it the same. And do it safely (no splashing, no tasting!, acid to water, etc)

 

[Tom Hoskinson]

Sorry, I do not mean to be pedantic, just to be clear, would you be as kind to explain this further. Only, I am a little bit confused as to why you don't just add the part 'A' and then the part 'B' of Pyrocat straight in to your final measure of water. The way you do it just seems to be an awful lot of messing about.


Regards

Stoo

Stoo, that is exactly the way I do it with Pyrocat.

I add the part 'A' and then the part 'B' of Pyrocat straight in to my final measure of water and mix.

 

[Stoo Batchelor]

Example: 1:1:100 of Pyrocat and total volume of 250ml. So I need 2.5ml of A and 2.5ml of B and 245ml of H20.

No, you will need 250ml of water if you were to mix to 1:1:100, and the total volume of developer would be 255ml. If you was to use only 245ml of water, you are not mixing at 1:1:100. Dam, now I am being pedantic.

Tom Hoskinson

Stoo, that is exactly the way I do it with Pyrocat.

I add the part 'A' and then the part 'B' of Pyrocat straight in to my final measure of water and mix.

Yes, so do I Tom, and any fluid left in the measuring cylinder can be slooshed out with the final mix.


Best

Stoo

 

[rwyoung]

No, you will need 250ml of water if you were to mix to 1:1:100, and the total volume of developer would be 255ml. If you was to use only 245ml of water, you are not mixing at 1:1:100. Dam, now I am being pedantic.

You are describing 1+1+100, not 1:1:100...

But at the ratios we are talking about, there is VERY little difference. Pick one way and be consistent, that is the real key.

 

[Stoo Batchelor]

You are describing 1+1+100, not 1:1:100...

But at the ratios we are talking about, there is VERY little difference. Pick one way and be consistent, that is the real key.

Dear rwyoung

As always, I like to be the one who is right (human nature)..but...I am a person who will always be happy to bow down to someone with superior knowledge to me, which is almost always when it come to the maths of photography

You tell me that 1:1:100 and 1+1+100 are not the same thing. According to the Pyrocat HD instructions, at least in the way Sandy has written them, they appear to be the same thing. I will quote from the Pyrocat HD instructions (taken from the web)

WORKING SOLUTIONS OF PYROCAT-HD

For developing negatives intended for printing with silver gelatin papers the recommended working solution is a 1:1:100 dilution.

One Part Stock Solution A + One Part Stock Solution B + 100 parts water.

Now, you can see my confusion. Thats if I am confused of course. As with all of the staining developers I have used, Di-Xactol, Prescysol, Pyrocat HD and Pyrocat M, I have always mixed them the same. One part 'A', One part 'B' to 100 parts water. i,e; 1000ml of water would have added to it 10ml of part 'A' and 10ml of part 'B', making a total solution of 1020ml. That is what I understand to be the correct way to mix Pyrocat.

You have obviously chosen to mix it to a slightly different mix, which, as you pointed out, there is VERY little difference, but lead me to question your mixing method in the first place.

Like you say, Pick one way and be consistent, that is the key. Never have truer words been said.

To the original O.P

Apologies for butting in on your thread. The simple answer to your question is 'either way' developer first or water first. Personally, I always add the developer to the water.

Best

Stoo

 

[rwyoung]

Stoo -

Yep, A+B vs A:B are often confused with each other. The A+B method is simpler but if you want to hit exact volumes without waste, the ratio method works every time. If you did want exactly 1000ml of Pcat at 1+1+100 you could just dump out the extra 20ml...

1+1+100 would produce 102 units of total solution while 1:1:100 should maintain a total of 100 units of final solution. At high dilutions there is very little difference. The verbage in Sandy's instructions are describing 1+1+100 but he has written it as 1:1:100. Sandy may at some point notice this thread and jump my case about the interpretation but I stand by 1+1+100 and 1:1:100 not being the same thing. Others who may jump on my interpretation are Ron (PE) and Gainer and probably Ian and a few others...

The whole upshot of the way I mix the stuff is to make sure I get all the small volume out of the measuring vessel into the mixing vessel. By NOT measuring out A, dumping into mixing vessel and then immediately pouring in the B without rinsing away all the A from the measuring vessel is that it won't contaminate the B with stock A before it is time to start the reaction/developing. All comes down to laboratory and handling practices.

Yes, the simple, two part answer is, "either way" and "be consistent". The third part would be run some simple exposure and developing tests to fine tune the formulas for your personal use. None of this is terribly complicated. It just sounds complicated, but then write detailed instructions for making a peanut-butter and jelly sandwich and it will sound complicated too!

 

[srs5694]

My understanding is that rwyoung is correct from a general chemical notation point of view; however, things are a bit different in photography. Consider a less concentrated developer, such as XTOL or D-76. These are often diluted with equal quantities of water -- 125ml of water with 125ml of stock solution to make 250ml of working developer, for instance. Kodak (among others) writes this as "1:1", which just doesn't make sense according to rwyoung's interpretation. Some others write this same dilution as "1+1." In other words, the two notations are equivalent in photography. At least, that's my understanding.

 

[Bruce Osgood]

Here's my take on all this.

Firstly, to be a ratio you need two parts, not 3 or more. Three or more is not a ratio, it is recepie or something else.

A ratio of 1:1 is an undiluted Stock Solution.
A ratio of 1:2 is diluting 1 part to make a volume twice the size. This would be the case of D-76.

 

[Tim Gray]

The general logic behind pouring the nasty chemical into the water is that if it splashes, the splashing liquid will be whatever was in the container to begin with and will get displaced. So, in most cases, leave the water in the container and pour in the whatever.

I think for things like D76 and XTOL, not that we want these all over us, it probably doesn't matter what order you do it since they aren't that nasty of chemicals.

 

[rwyoung]

Here's my take on all this.

Firstly, to be a ratio you need two parts, not 3 or more. Three or more is not a ratio, it is recepie or something else.

A ratio of 1:1 is an undiluted Stock Solution.
A ratio of 1:2 is diluting 1 part to make a volume twice the size. This would be the case of D-76.

1:1:100 is still a ratio. It is short hand for 1:100 of A and 1:100 of B, two ratios with a total final volume of 100 units. Confusing, isn't it.

The A+B notation is much more understandable and natural to use with liquid measures. But somewhere along the way the ":" and "+" became considered to be interchangeable when they really aren't.

1:1 should be a stock solution (all stock, no dilution), 1:2 would be equal parts stock and water (or whatever the diluting fluid would be). These would be 1+0 and 1+1.

But to make things worse, in English we would say 1:1 as "one to one" and interpret that as 1+1.

What a mess! Time to stuff the worms back into their can!

 

[Bruce Osgood]

What a mess! Time to stuff the worms back into their can!

I agree, but some days pedantry and nit-pick are all there is.

 

[srs5694]

1:1 should be a stock solution (all stock, no dilution), 1:2 would be equal parts stock and water (or whatever the diluting fluid would be). These would be 1+0 and 1+1.

"Should" and "would" are two different things. In practice and in the field of photography, "1:1" and "1+1" are synonymous and mean equal parts of the two items. You can rail against this, and even be right in doing so on some level, but IMHO it's important that confusion (particularly for newbies) be kept to a minimum, and that means describing the notation as it's used on Web sites, in books, etc. As has been pointed out before, the difference is tiny when dealing with highly concentrated stock solutions such as Rodinal, but if somebody learns that "1:100" means one part of stock solution plus enough water to make up 100 units of working-strength solution, then that person will get things badly wrong when switching to a product that calls for "1:1" or "1:2" dilution.

 

[rwyoung]

srs5694 -

YEP! "Should" and "would" are definately different beasts! Both of which will come back and bite you at any time.

I try to use the appropriate symbol ("+" or ":") depending on what I'm doing or describing. For low dilution stuff (like Dektol for example) I try to make all my notes using the + notation. But when I'm mixing up stuff at higher dilutions or for use in the Jobo (which really doesn't like too much of a fluid load) I generally use the : notation. This is because at high dilutions I want to be sure I have the minimum amount of developer necessary for the surface area of film (wanna start another war on how much Rodinal/A09/Parodinal it really takes per 80 square inches. Is it 2.5ml? 3ml? 5ml? Ha! Depends on what data sheet you read or who you ask!). And I want to hit the fluid volume on the button so as not to overload the Jobo's motor.

And yes, I see the irony in my arguing this point and what my SIG says... That is why I picked the SIG, to remind me that in the larger scheme of things, it isn't that important so long as its done consistently.

Go forth and mix to your heart's content. As Mr. Lehrer says, "Hearts full of truth, Six parts gin to one part vermouth"!

 

[gainer]

in any case, do not mix the A and B parts without water. If you do that, you have an active developer solution that is many times more susceptible to aerial oxidation than will be the final solution. It could be nearly dead by the time you measure in the water.