Mixing xtol on a per roll basis?

[tomfrh]

I had an earlier xtol failure and since then have been mixing it up on a per roll basis.

Someone has told me this is a real bad idea because the powders are too heterogenous to get a proper mix of the constituent chemicals when taking only teaspoons at a time.

It's worked for me so far, and each powder looks fairly well mixed. It's not like they've settled into layers from what I can see. If it wasn't mixed I'd simply give it a shake.

What do you think?

 

[mgb74]

I think you've been lucky.

 

[MattKing]

A 5 litre bag of X-Tol will develop 70 rolls of film if you use it in a replenishment regime. In my area, where it costs $10.00 CDN for a bag, that is $0.14/roll. If I used X-Tol 1+1 and used 300 ml of working solution each time, my throughput would go down to 33 rolls per bag, and my costs would go up to $0.30 per roll.

If my use went down to even half of that, and I had to throw away 2.5 litres at the end of 6 months, I still would be able to develop at least 16 rolls from each bag, at a cost of $0.60/roll.

There truly is no meaningful cost advantage to trying to stretch that out.

If you try to split the powders into smaller amounts, and then use those smaller amounts individually, you will get inconsistent results. It is not practically possible to ensure homogeneity

If you want a bag of X-Tol to last longer than 6 months after mixing, mix it in good water and split it into 5 well sealed one litre containers with little or no air in them. It is a better use of your time to do activity clip tests prior to each developing session after 6 months has elapsed, then to spend the same or more effort and time ensuring that your division of the powder is even and consistent each time you develop a film.

Folks, the solution to this "problem" is to either shoot more film, or transition to something like HC-110, or mix your own developers from scratch chemicals.

 

[Gerald C Koch]

How many times must it be said before it sinks into the collective APUG conscience that it is a really bad idea to try to divvy up powder mixes.

There are two solutions the OP's problem. Either shoot more film or switch to something like HC-110 which lasts forever and is used as a one-shot.

 

[Sirius Glass]

That is a bad idea. See post #4.

 

[StephenT]

Years ago, perhaps I should say decades, one of the photography magazines (consumer magazines) had an article about using measuring spoons to mix small quantities of powdered chemicals as needed. It was a very detailed article. I saved it and for a little while applied the principles without issue. Or rather, without a known issue.

However, having learned more about the chemistry involved, I would never do that now. XTOL is cheap enough - I am still using a batch mixed in August of last year (replenishing at the rate of 70ml per 80 sq. inches). If it goes unused for a couple of weeks, I add about 100ml to each liter of working solution. I use it at stock solution undiluted. I buy it in the 5 liter bags. I also do a clip test before using the working solution if it has been unused for a while. I keep the working solution in one liter amber boston rounds topped off to the very top and then closed with a polyproylene cap so that there is no air in the bottle. The stock solution I use for replenishing is topped off with an inert gas.

When it come to developing film, be safe - not sorry.

 

[slm]

I was lucky enough to get my hands on some empty, 5L "box wines" - the wine is stored in bladder inside the box and is poured out from a spigot. I say lucky because usually the box wines here in Canada are 4L, these were from the states and are of the correct size. It really stores the developer well and is so convenient for pouring, but best of all its a great excuse to buy some wine and drink it all up !



Steven

 

[henpe]

Someone has told me this is a real bad idea because the powders are too heterogenous to get a proper mix of the constituent chemicals when taking only teaspoons at a time.

I do not mix on a per-roll basis; I am too faint hearted. However, I cannot refrain from thinking that the heterogeneous thing is exaggerated? How does Kodak get the powder into the bag? Do they weight and mix the powder on a per-bag-basis? I guess not So certainly, the powder must be homogeneous enough to allow splitting from a large batch into smaller units...my two cents

Henrik

 

[MattKing]

I do not mix on a per-roll basis; I am too faint hearted. However, I cannot refrain from thinking that the heterogeneous thing is exaggerated? How does Kodak get the powder into the bag? Do they weight and mix the powder on a per-bag-basis? I guess not So certainly, the powder must be homogeneous enough to allow splitting from a large batch into smaller units...my two cents

Henrik

There is a couple of different ways it is done, but the most common is to place just the right amount of each of the constituent parts into each bag, and let the mixing happen in the bag itself.

 

[ColColt]

I just got the Xtol yesterday and got a 2 gallon food grade bucket at Lowe's to mix. I stored the solution in 4 1 liter brown bottles and two 500ml bottles. That makes a lot of developer!

 

[tomfrh]

However, having learned more about the chemistry involved, I would never do that now

Could you elaborate on the chemistry? Why is it so sensitive to minute imbalance of constituent chemicals? Is it the orange sprinkles that can be the issue?

When it come to developing film, be safe - not sorry.

That's what I thought I was doing mixing it as needed! I figured I couldn't do worse than the total failure I'd had previously!

 

[ic-racer]

Try t-max developer, if you want to mix it up just before you use it.

 

[StephenT]

tomfrh: I don't think minute differences would really make a significant difference, unless the quantity of some chemicals were already at the trace level. There's always the issue of settling, oxidation, breathing the stuff after you vigorously shake it up again, etc! It worked for me for a while, then my dry chemicals started to turn to rock hard clay-like stuff so I gave it up!

 

[Gerald C Koch]

Kodak and other manufacturers have spent a lot of money on powder mixing machines. Back when D-76 was supplied in cans I have opened a can and found all the hydroquinone at the top of the mix. Hydroquinone crystals have a distinctive needle shape and are easy to identify..

https://www.alibaba.com/premium/powder_mixer.html?ptsid=1012001001276812&qstr=powder mixing equipment&mt=p&bmt=bb&kwid=39116883506&adid=7310465433&device=c&ptscode=0210202010050001&uptime=20150204

Large bathes of mix are made and then placed in the bags. Once in the bags and subjected to vibration the constituent chemicals tend to separate.

Kodak did a lot of research into preparing stable powder mixtures and hold many patents. In one patent the developing agents are protected by a coating of very fine boric acid anhydride powder. However once the container has been opened these same protectants can actually cause harm to the mix. The contents are designed to be mixed immediately upon opening and not left around exposed to the air and moisture.
Because of these patents Kodak can supply D-76 in a single bag whereas Ilford must use two bags for the identical ID-11.

 

[tomfrh]

Is this why they yanked the 1 litre XTOL packs? Too much chance of scooping up a non representative sample?

 

[Gerald C Koch]

Is this why they yanked the 1 litre XTOL packs? Too much chance of scooping up a non representative sample?

Kodak was never able to pinpoint the exact problem. But the packaging equipment used for the 1 liter bags was suspected as one cause.

 

[HiHoSilver]

'Just a tip o' the hat to Matt & Gerald. 'Good replies & gives good reasons it should not be done. I appreciate your excellent help.

 

[selmslie]

I had an earlier xtol failure and since then have been mixing it up on a per roll basis. ... What do you think?

Probably not a good idea. The powder may not keep well after opening either. Because of the horror stories I had already read, I got a tank with a floating lid. It will keep the Xtol from going off for up to a year after which I just dump it and replace it.