Tap water

[maris]

I have only used tap water for darkroom work in many places, at many times, over the last five decades. There have been problems from time to time but none of them traceable to tap water. My present 1.6 litre batch of Xtol (replenisher system) is five years old, had hundreds of rolls and sheets of film through it, and works reliably and predictably. Only tap water has been used for mixing the replenisher.

 

[Josh66]

Until now, I have only used tap water too. What can I say ... it just stopped working one day. I don't know if it's chlorine, the pH, copper, or whatever else it could be... I haven't had the water tested yet, but it's pretty clear to me that the water is the problem. Just like Cruzingoose, it just didn't work. Tap water was working fine, then I couldn't develop anything with it so I tried distilled water. That worked fine. Tried tap water again just to make sure I wasn't crazy, got the same results again... I've been using distilled water since and haven't had a single issue...

After Pete from Kodak said that generally, if it's safe to drink, it's safe for film - I'm wondering if my tap water is safe to drink.

 

[ann]

gosh, it's photography fun. Many times the gremlins invade the darkroom and drive us crazy. However, it appears you have taken the proper steps in figuring out what is happening but it isn't fun to discover its the water of all things.

When I moved from St. Louis to Atlanta many years ago, I ran a couple of test to be sure my development times would be the same. Luckily that happen to be the case; however, I was prepared for a huge difference, especially with regard to contrast.

 

[DannyD]

I would not recommend distilled water for developpers ! The distilled water pH is acid (5 to 5.5) because of the chemical reaction between carbon dioxid and distilled water. Since developpers are Alkalis, they don't like to be mixed with an acid.

The best water for developpers is usually tap water. If it doesn't work, use some drinking water sold in plastic bottles. It's cheaper than distilled water and the pH is really neutral (7).

 

[Cruzingoose]

I would not recommend distilled water for developpers ! The distilled water pH is acid (5 to 5.5) because of the chemical reaction between carbon dioxid and distilled water. Since developpers are Alkalis, they don't like to be mixed with an acid.The best water for developpers is usually tap water. If it doesn't work, use some drinking water sold in plastic bottles. It's cheaper than distilled water and the pH is really neutral (7).

Just tested some of my homemade steam distilled water and the test strip indicated a 7.2 while the water from the dehumidifier measures a 7.8. I guess it all depends on what you start off with. Our local WallyMart has steam distilled water for 79 cents a gallon. But even if it is a buck a gallon and used for mixing developer only it is still a better and more consistant "solution" to the problem.

 

[DannyD]

What you said is very interesting. Usually, distilled water is acid (ph = 5) after a while because of this :

Distilled water ideally consists of only hydrogen and oxygen, with a completely neutral pH of 7. In reality, it almost always is slightly acidic, from 5.6 to just under 7, because the water absorbs carbon dioxide from the air. A gallon of distilled water can be made neutral by adding 1/8 tsp. of baking soda, a substance with a pH of 8.

and here :

Pure water has pH 7, so still, freshly distilled water should have a pH of 7.0. However, interaction with the atmosphere allows carbon dioxide to dissolve into it, forming carbonic acid. As a result, agitating the water or allowing it to sit for a while will leave you with an aqueous solution that drifts down in pH. Because there are no natural buffers in distilled water, the pH can go down as low as 5.0.

I can say that Distilled water sold in stores is already stabilized. There is no problem using it.

Our local WallyMart has steam distilled water for 79 cents a gallon.

Simply amazing ! Here in europe, you will pay $25 (19 euros) for 5 liters...

According to this, Distilled water for developping may be a good solution.
​

 

[Josh66]

Simply amazing ! Here in europe, you will pay $25 (19 euros) for 5 liters...

Wow. That's insane. Distilled water is $0.84 per gallon (3.78L) at my local Walmart.

 

[DannyD]

Simply amazing ! Here in europe, you will pay $25 (19 euros) for 5 liters...

Wow. That's insane. Distilled water is $0.84 per gallon (3.78L) at my local Walmart.

That's europe : low incomes, high prices !

Distilled water : Eau distillée, stérile by: AGUETTANT - www.socimed.com - Vente de
This one is for medical and healthcare, sterile. A real distilled water.

An alternative is "demineralized" water. It's cheaper and sold for steam irons, steam household cleaners, etc... But not so pure than distilled water
Bidon 5 litres eau déminéralisée - RueDuCommerce

It's cheaper, but pricey : $7,45 for 5 liters, wich means $5,63 for a Gallon !

Who said everything was cheaper in Europe ? Not me !

 

[Helen B]

If distilled or deionised (DI) water is available locally and cheaply I always use it for making up developers. I've had problems with tap water in some parts of the world so I reckon that if it is an easy, cheap potential problem to avoid, I avoid it. In the professional still and motion picture labs I have worked in we always used DI water. It shouldn't matter too much with prepared Kodak developers - they are generally well buffered and contain a sequestering agent, though iron can be a problem with Xtol. I've never had a problem with the pH of distilled water - the stuff you buy isn't pure water, by the way (unless you buy it from a nuclear power plant of course). The simple jug-type water filters usually use some kind of ion exchange resin which is cheap and works OK for small daily volumes.

 

[DannyD]

I've never had a problem with the pH of distilled water - the stuff you buy isn't pure water, by the way (unless you buy it from a nuclear power plant of course).

You woke up the scientist I used to be (Chemistry Teacher).

Pure water (not specially used in Nuclear plants, we can find it in schools and Pharmaceutical industry, even you local Pharmacist uses it) is lightly acid vith a pH around 5.5 due to CO2 dissolving in pure water, leading to a chemical reaction resulting into Carbonic Acid


2 H[SUB]2[/SUB]O + CO[SUB]2[/SUB] --> H[SUB]2[/SUB]O + H[SUB]2[/SUB]CO[SUB]3[/SUB] (Carbonic Acid)

That's the reason why schools uses a special distilled water (Buffered) with a neutral pH for some lessons (Chemistry labs with low concentrations).

Sounds logical there is no problem with the pH of distilled water if you're using a buffered distilled water with a pH of 7...

 

[Cruzingoose]

Perhaps the pH changes with time after the water is distilled from steam, and if it does, I never noticed it. My water from deep underground may not have a lot of disolved CO2 it. and with a pH of 9+ before distilling, moving a few points to 7 indicates it does lean to acid. I imaging the recovered water from the dehumidifier is slightly more alkaline because of the alkaline dust in the air here on the Prarie. I know the dirt here is very alkaline because it turns white around dried ponds and battery acid (H2SO4) poured on it (to kill weeds), foams up nicely.

Either way, anything that eliminates a variable and improves consistancy is good.

 

[Josh66]

I'll have to get some test strips and see what mine is... Not really worried about it, but I'm curious now.

 

[ann]

Some place hiding in the darkroom is a device I used off and on for measuring the ph of the water. Used it mainly for alternative processes. Haven't used it a long time. As I remember it wasn't expensive.

 

[KenC]

Try gardening supply places - some gardeners are obsessed with pH and use aluminum sulfate or lime to lower or raise soil pH, respectively - they usually sell pH paper or other measuring devices.

 

[Helen B]

Pure water (not specially used in Nuclear plants, we can find it in schools and Pharmaceutical industry, even you local Pharmacist uses it) ...

When I mentioned pure water and nuclear power plants in my 'by the way' I was referring to the purity. It is very unlikely that the water used in a school lab or by a pharmacist really is pure water and only water - that stuff is difficult to make and it is also difficult to contain for any length of time. Why would a pharmacist use 0.055 µS/cm water when the standard is about 1.3 µS/cm (referred to in the pharma industry standards as 'purified water', not 'pure water' which is the next higher grade)? Most of us can settle for water which is less than pure.

If you are worried about using distilled water because it has a pH of less than 7 then ask yourself whether or not there is a significant difference at equilibrium between solutions made with distilled water and good quality tap water. Why should there be significantly more carbonic acid in the distilled water solution than in the tap water solution? The use of distilled water is recommended in a number of photographic chemistry reference books, including the popular Film Developing Cookbook, and it is specified in some method statements for labs processing archival materials.

Best,
Helen