510-Pyro in demineralized water -- further tests

[Trask]

A few weeks ago I posted regarding the apparent effect of using demineralized water with 510-Pyro -- the resulting negatives were very thin. That thread is at (there was a url link here which no longer exists)

To test those initial results, I did some testing to determine if, all other things being equal, the difference in water makes a difference with 510-Pyro. I shot an entire roll of Legacy Pro 100/Acros in a Contax Aria, one lens, all photos within a ten or fifteen minute timeframe on a sunny day. Cut the roll in half in the changing bag, loaded two tanks. Develop in 510-Pyro semi-stand 1:400 (same volume of solution in each tank) at 75F for 35 minutes, with identical agitation every five minutes, only difference is one solution was with demineralized water and the other with Brita jug filtered tap water. I did 1:400 because that's what I had done in the first instance where the resulting negatives were very, very thin, so I wanted to see if that happened again.

The results, show below, are that the film in demineralized water has lower apparent contrast than the film developed in tap -- visible, but not drastic, I'd say. The results with demineralized water are much, much better than my first effort that led to the first thread, so I can only think that (A) the lack of agitation the first time markedly cut down on development activity, or (B) I had made some error in the first test. You can see that when I cut the film I cut through a picture, so it's easy to see the difference in that frame and in the frames to the left and right.

As a result of these tests, I'm going to stick with filtered tap water. I recognize that the negatives here developed in tap water appear over-developed; my intention in this test was to get images on film. Now that I see the results of 35 minute stand with agitation every five minutes, I can fine-tune.

As an aside, I've also included an image of these test negatives and those of Legacy Pro 400/Neopan 400 in 510-Pyro (on the left), where the all the film including the sprocket area is stained -- it may not be very visible in the image, but the Neopan 400 film is noticeably darker all over than the Acros -- perhaps there's some difference in the film base.

 

[Doremus Scudder]

Interesting. There may be something in your tap water that activates the developer to some extent. I find that I need to develop about 10% less when using harder water (lots of calcium carbonate) and PMK than when using tap water that is softer. Maybe something like this is affecting your results.

Doremus

 

[craigclu]

I had some similar issues some time ago and posted on APUG for advice. At the time, I had access to a free source of deionized water and experienced an initial experience like yours. I was involved with some projects at work that had some clear direction on what/when not to use deionized water as it hindered some reactions that we were attempting to trigger. I also found that the terms related to forms of water were not consistent (distilled doesn't necessarily mean distilled anymore). I don't pretend to have any chemistry skills beyond my hobbyist approach to photo applications and I returned to tap water for the bulk of my uses and enjoy very good and consistent local water (and results). I use store-bought "distilled" for my base chemistry but mix to tap when diluting for use and get very consistent results. Just looking now because of your post, I found a nice summary of definitions as a good overview:

http://tinyurl.com/qbvxkej

A company chemist at the time made a casual remark of certain things requiring more available free ions for
reactions to be made at faster and more reliable rates.... Perhaps someone with some real knowledge and not my anecdotal experiences could assist?

 

[georg16nik]

I had some similar issues some time ago and posted on APUG for advice. At the time, I had access to a free source of deionized water and experienced an initial experience like yours. I was involved with some projects at work that had some clear direction on what/when not to use deionized water as it hindered some reactions that we were attempting to trigger. I also found that the terms related to forms of water were not consistent (distilled doesn't necessarily mean distilled anymore). I don't pretend to have any chemistry skills beyond my hobbyist approach to photo applications and I returned to tap water for the bulk of my uses and enjoy very good and consistent local water (and results). I use store-bought "distilled" for my base chemistry but mix to tap when diluting for use and get very consistent results. Just looking now because of your post, I found a nice summary of definitions as a good overview:

http://tinyurl.com/qbvxkej

A company chemist at the time made a casual remark of certain things requiring more available free ions for
reactions to be made at faster and more reliable rates.... Perhaps someone with some real knowledge and not my anecdotal experiences could assist?

“...distilled doesn't necessarily mean distilled anymore...”???
Perhaps you are thinking about solar distillers vs steam distillers? The carryover depending on source water and process vary but you can add activated charcoal filtration and you are all set in case you wanna be pedantic.
Even a single pass, steam distillation is more than good enough for photo applications.

 

[Gerald C Koch]

There is a problem in using extremely dilute developers. The resulting working solutions are usually very poorly buffered and have little protection to aerial oxidation during use. Therefore they are particularly susceptible to producing irregular results.

In the case of 510 Pyro you are starting with a concentrate which already has a low concentration of developing agents and anti-oxidant and then diluting it 400 times. A liter of working solution contains only 0.125 g of antioxidant/developing agent as ascorbic acid and 25 milligrams of pyrogallol. Compare this to the working solution of a typical acutance developer like the Beutler formula. It contains 10 g of antioxidant and 1 g of developing agent per liter.

 

[craigclu]

The containers of distilled water purchased at Walmart or grocery stores in my area all state that they are processed by microfiltration, ozonation, reverse osmosis, etc. They can still be sold as distilled water. Perhaps it doesn't make any difference but the term has been distorted to mean different things than distillation (as my assumption had led me to believe).

 

[georg16nik]

The containers of distilled water purchased at Walmart or grocery stores in my area all state that they are processed by microfiltration, ozonation, reverse osmosis, etc. They can still be sold as distilled water. Perhaps it doesn't make any difference but the term has been distorted to mean different things than distillation (as my assumption had led me to believe).

So, its just a label. That's not nice for certain purposes and consistency.

 

[Trask]

I take your point, Gerald, about the dilution rate I've used, but as the results show 512-Pyro seems to have no problem developing even at 1:400 and with relatively little agitation to flush fresher developer across the emulsion -- though my prior experience with absolute stand for 40 minutes showed signs of bromide drag, hence the agitation at five minute intervals. I can't say that the negatives look any less developed than those that I developed at the standard dilution of 1:10 for 8-10 minutes. I have yet to do any scans so can't speak to any difference in grain or tonality.

Doremus has suggested some element in the tap water -- that's very likely, as the water here in Paris is known to be hard, and sediment stains on bathroom sinks etc is a common problem. I suppose that the next test would be to develop yet more Acros in the 1:400 dilution using demineralized water to see if, by extending time, I can arrive at negatives that have the same contrast as those we see here as developed in tap water. I would expect that I would be successful, but nonetheless a test would be useful to see if the resulting negatives were as dense but perhaps in some other characteristic somewhat different.