Dividing up a pack of XTOL

[machine]

Why scare yourself with the idea of 10 litres?
You mix and store the stock solution. If necessary, you can mix it at a higher concentration and store it in 4 one litre bottles.
If you intend to use it 1 +1, just dilute the more concentrated stock 1 + 1.25.

I had thought of (and tried to avoid) storing 5L (I understand the stock is diluted just prior to use; worked with D-76 many many years ago when I had more space.

If I were to work with 4L concentrated stock solution - in order to make it up to 1:1 I would need to mix 1:1.5, and not 1:1.25, right?

i.e. 4L + (1L short) + 5 L water = 4L concentrated stock + 6 L water i.e. 1:1.5

I am ordering the XTOL today, and will also need to get the bucket / bottles to store the concentrate. So some ways away from using it, but should get there in a couple weeks.

 

[MattKing]

If I were to work with 4L concentrated stock solution - in order to make it up to 1:1 I would need to mix 1:1.5, and not 1:1.25, right?
i.e. 4L + (1L short) + 5 L water = 4L concentrated stock + 6 L water i.e. 1:1.5

We have a problem with terms here.
One of the reasons I avoid using ratios - i.e. using the ":" symbol - is that there is potential confusion between whether the ratio is between the component parts (which is how Kodak documentation does it), or between one component part and the resulting solution as a whole (which is more common with chemists).
For that reason, it is more clear and simple to use the "+" symbol.
With the more concentrated stock solution (4 litres instead of 5) you would add 4 litres of stock plus 6 litres of water (4 + 6) to get 10 litres of what is more commonly referred to as 1 + 1 working developer.
Or more practically, 200ml of concentrated stock plus 300ml of water, to get 500ml of what is more commonly referred to as 1 + 1 working developer.

 

[john_s]

I have managed to get a 5L batch of Xtol to dissolve in 2.5L and it seemed to keep well. Dilution is straightforward.

 

[Nicholas Lindan]

Speaking from experience in the clinical chemistry (AKA blood analysis, as in Dr. Richard Henry) industry where powders have to be mixed and then dispensed into vials (thinking of the shot you got? Well, it's the same technology, but my experience isn't in pharmaceuticals)...

Mixing powders isn't a big deal. You can, of course, do it wrong, but you have to work at it. Shake it up well and it will divide pretty evenly. It's photography after all -- get it to within 10% and you are golden. Heck, the exposure is probably off 50% of optimum, and development is off another 50% -- VC paper to the rescue.

The problem you may have, if you live in Florida, is a dry environment for your stored division of the powder. I'd suggest using a pickle jar (or any other glass jar with a tight lid - I'm sure Wilkin's Tiptree Tawny Marmalade will work) and then tossing in a desiccant package. Some photographic chemicals are photosensitive, glycin comes to mind. I have no idea about XTOL clones.

* * *​

Clinical chemistry and darkroom photography have a large overlap - control of chemical dilution and addition, precise temperature control, agitation control, production of color change, and measurement of optical density. Or, in some cases, production of an electrochemical reaction and measurement of same.

 

[machine]

XTOL's on the way. I had initially planned to mix it in 1L batches (I think it would have worked out, esp. given parts A and B are separate and I figure I can mix powders well enough, certainly within bounds of the other parameters) - but now I am going to mix it all to make 4 liters (i.e. concentrate) and dilute 1:1.5 by volume to end up with 1:1 XTOL solution. I have also ordered a 5L jar/beaker. I figure I can use it long term given I plan to use powder developer (specifically XTOL) from now on. I was specifically looking for a low toxicity developer to teach film developing, and very much want to make XTOL work. So, why risk it given I really want it to work.

The Massive Dev Chart times for XTOL have inconsistencies for the films I'll be using, so I expect to have more questions of the kind folks on this knowledgeable forum.

Here are the times I have planned to use later this week (all XTOL 1:1, box speed, 35mm & at 20 deg C / 68 deg F) -
- HP5 - 12 mins
- Kentmere 400 - 12 mins
- FP4 - 10 mins
- Kentmere 100 - 10 mins
- Arista Edu (Foma) 200 - 9 mins

Please let me know if you have a better starting point! Many thanks all.

 

[Juan Valdenebro]

Hi machine,
More important than the development times for your films, will be the amount of light (EI) each film requires for reaching the best image structure in every developer.
HP5+ is great in Xtol at EI400 and even at 500-640, while FP4+ produces much better image structure in Xtol and other developers when exposed at EI64.
The same with other films.
What I mean is, it'll be after you test your films for some time, and decide their optimal EIs, that you'll be really able to set the optimal development times for each film.
In other words, it's not development what makes a film be the best it can be: it's exposing it properly, and developing it the optimal way for the optimal EI you found after testing.
Films are a product to be sold, so their boxes talk about a possible way to use that film: usable, but not always optimal.
Enjoy!

 

[machine]

Hi machine,
More important than the development times for your films, will be the amount of light (EI) each film requires for reaching the best image structure in every developer.
HP5+ is great in Xtol at EI400 and even at 500-640, while FP4+ produces much better image structure in Xtol and other developers when exposed at EI64.
The same with other films.
What I mean is, it'll be after you test your films for some time, and decide their optimal EIs, that you'll be really able to set the optimal development times for each film.
In other words, it's not development what makes a film be the best it can be: it's exposing it properly, and developing it the optimal way for the optimal EI you found after testing.
Films are a product to be sold, so their boxes talk about a possible way to use that film: usable, but not always optimal.
Enjoy!

That is very well explained, and extremely helpful. I (sort of) had an inkling, but now have a much better understanding. Thanks.