Distilled/Deionised water, are they interchangeable?

[ChrisCummins]

Hi,
tomorrow I have the final materials turning up in the mail so that I can start developing my own film. However, I don't trust the water in this somewhat decrepit uni accommodation, so I am planning on using distilled water to be on the safe side.

A quick wander around Birmingham high streets revealed that distilled water is not such an easy thing to come by, however, apparently deionised water can be a suitable substitute for most applications of distilled water. Is this applicable to film processing? What are the risks of using impure water, and are the negatives worth the extra hassle?

Regards
Chris

 

[greyelm]

I am a retired scientist so have used both distilled and de-ionised water over the years. For most uses de- ionised water is fine, however it is worth checking the pH, it was only for very specialised biological solutions that we had to use distilled. I haven't done any wet processing for 30 years but I would be surprised if de-ionised water wasn't suitable.

 

[pgeobc]

Well, after having used both for many years, I can tell you to quit worrying. First off, when I was a kid in the 1950s, all we used was tap water; the slight amount of alkali in most city water supplies is not an issue for a normally alkaline process like photography. However, that is not universally true.

When it comes to the distilled vs. deionized issue, be aware that there are even different grades of distilled water (some, for very fussy puropses) and that plain, old, deionized water is adequate any day of the week, here.

Purchase from a reputable supplier or buy a small deionizer and make your own. I wouldn't be surprised if one could be had on eBay, along with the requisite meter to check purity, for a very reasonable price.

 

[Freakscene]

If you're mixing up a developer that uses ascorbate as a developing agents (e.g. Kodak Xtol) or your tap water is low quality (and this can include having old pipes) using deionised water is a good choice. it is also wise to use it for a final rinse to aid in preventing drying marks.

Deionised water has the ions removed using resin blocks, reverse osmosis, carbon filtration, microfiltration, ultrafiltration, ultraviolet oxidation, or electrodialysis, among other methods. Distilled water is heated until it boils and then it is recondensed. Both methods have risks for contamination and residual products that you don't need to worry about. For photo purposes decent deionised OR distilled water will be fine.

One thing to watch out for is that commercial deionised/distilled water often has particulate material in it. if you find you are getting spots on your negs, you may have to filter it. You definitely need to filter tap water.

Marty

 

[ampguy]

I would go with RO filtered water, this will be the most pure water you can get easily and inexpensively, perhaps your neighbors may have an under-sink unit and you could fill some jugs there. RO filtered water is purer than de-ionised water (called soft water in the US), and can be purer than distilled water, with regards to certain organic compounds that don't distill out at low temps.

All of the distilled water I've tested from Calif. supermarkets has been under 3 units of TDS, which is one of the definitions for distilled water. Aquafina, a drinking water brand, also often meets this criteria, though if you just drink Aquafina, you'll probably want to take some vitamins and minerals regularly, not sure if your film will need that though.

 

[Zonan]

I use R.O water and it does the job.

 

[ChrisCummins]

Thanks for all the replies. One thing that completely lapsed my mind at the time of writing was the fact that I'm at University, and by asking the right people I can probably get access to some filtered water. I would be very surprised if the Uni doesn't have water filtration in it's science labs, or at least would know of a source for it.

For the minute, I've decided to give tap water a go. Since this is my first time developing, I can't tell outright if the negatives are suffering because of this. I will try and get a gallon of distilled/de-ionised water and see if the negatives are somehow improved by using it. I am definitely concerned about using tap water for the dilution of solutions though, especially since I use Diafine. With a shelf life of well over a year, I expect that would give ample time for any impurities in the tap water to take effect.

Are there any symptoms of low quality tap water I should be keeping my eye out for?

Regards
Chris

 

[tlitody]

If its hard water then you will likely get bad drying marks which is a real pain to remove from film. Deionised or Distilled are fine. Usually I use one or other for mixing stock developer, then tap water for everything else except final rinse where I'd use distilled or deionised to minimise residual minerals from water leaving drying marks on film. If you do get drying marks be careful removing them as they cn scratch film if its bad. Remove as much loose water from film before hanging to dry.
A simple britax household water filter can remove a lot of minerals from hard tap water.

Standard developers should not be affected by tap water variations but occasionally it can happen with more finicky developers.

 

[Jaans]

I've been using Deionised water where I am as there is no shelf product labelled distilled water. Anyway, the negatives always turn out fine. There is similar thread running parallel to this that has some valuable information provided by Roger Hicks. If you can I suggest that you read that too, as it has some important information. Cheers

 

[Freakscene]

Are there any symptoms of low quality tap water I should be keeping my eye out for?

Diafine is very tolerant of water quality. The main thing to watch out for is drying marks on your negatives. If these prove a problem, try a final rinse in deionised/distilled water before using it for other steps in the process. Just getting the ions off immediately before you dry the film is usually enough to get clean negs.

Marty

 

[Matus]

I am not sure which of the two is more suitable for film processing, but it does make it a good start to read about Purified Water on Wikipedia which describes both briefly.

 

[ChrisCummins]

I've developed about a dozen films now and have yet to see to see anything which I would attribute to drying marks. There have been some 'ink blot' style marks on a couple of rolls, but that was when I was experimenting with the wash method. I use this method now, and it seems to work fine:

1 - Tap water, 10 inversions, drain.
2 - Tap water, 20 inversions, drain.
3 - Tap water, 40 inversions, leave to stand for a couple of minutes, drain.
4 - Tap water with 5 drops of photo-flo in, 20 inversions, drain.
5 - Tap water, 20 inversions, drain. Hang film up to dry.

The first three steps are the Ilford wash system. From what I gather, most people use photo-flo as the very last step but I haven't had the courage to since directly after application of photo-flo the negatives are covered in bubbles?

Regards,
Chris

 

[tj01]

Add wetting agent to water, stir, bubbles form, let it sit, bubbles become less, then only dunk the negs in right at the end of your process. Do this at the start of your routine, but use it only at the end.

 

[gliderbee]

I use R.O water and it does the job.

What is R.O water ?

I'm using condensed water from the laundry dryer for mixing developer and with some wetting agent at the end.

Stefan.

 

[ampguy]

reverse osmosis

reverse osmosis

http://en.wikipedia.org/wiki/Reverse_osmosis

What is R.O water ?

I'm using condensed water from the laundry dryer for mixing developer and with some wetting agent at the end.

Stefan.

 

[Lilserenity]

Where I live in West Sussex the water doesn't get much harder, as much of our water comes from chalk aquifers under the South Downs.

I use de-ionised water quite extensively, bought from Halfords. I use it to make up the developer (whether 1 shot HC-110 or D-76 up to a US gallon), but the stop and fixer I use normal tap water, as I also do for the final wash (~10-15mins), but the final rinise (20 inversions thereabouts) in deionised water, then I use a big plastic container with some more fresh deionised water, not too deep, say about 3/4 - 1" of water, couple of drops of Photo Flo and see-saw the length of the film through this a 3-4 times, then hold up over the shower basin to let the excess water run off, then hang to dry (with a clip at the bottom so it dries flat.)

Works a treat and the economy of this method is quite good, and I rarely get any specs of drying marks etc. if I do they're minor.

This took quite some time to perfect this method!

Vicky

 

[Chris101]

I am a retired scientist so have used both distilled and de-ionised water over the years. For most uses de- ionised water is fine, however it is worth checking the pH, it was only for very specialised biological solutions that we had to use distilled. I haven't done any wet processing for 30 years but I would be surprised if de-ionised water wasn't suitable.

If you wish to check the pH of distilled or deionized water, then use an indicator strip, not a meter. With high purity water, the meter will give you the pH of the last solution that it was dipped into. There are not enough ions in purified water to carry the tiny current needed to make the meter work correctly.

----

Actually the purity of the water will have little effect on all but the final rinse. The amount of chemicals in the developer, stop (if you use it), hypoclear (again, if you use it) and fixer will overwhelm anything that is in potable water. You can even wash the film in hard water, but then do use some sort of purified water (distilled, de-ionized, reverse osmosis, or elix filtered) to prepare your final (photo-flo) rinse.