finding it hard to get deionised water!

Ian Grant · Jul 30, 2012

De-ionised water is by far the cheapest and also best option, at least in the UK, distilled water needs energy and that's expensive outside the US.

Before deionised water became easy to buy or do for yourself the best water was double distilled and that was expensive, now you deionise or use reverse osmosis first before distillatrion but thats overkill for photography, except specialist emulsions.

Ian

salan · Jul 30, 2012

Photo Engineer said:
Distillation removes all inorganics and destroys or removes many organics. Particulate matter is left behind. From a volume distiller DW is easy to make and can be quite inexpensive.

Deionized water is made by running water through a mixed bed ion exchange resin which can be quite slow and quite expensive when compared to distillation.

The resin, once used, must be either discarded or regenerated, but a still can be kept operational for weeks or months at a time. They do need cleaning every once in a while to remove mineral scale.

For high end use, DI DW is used for ultimate purity. We at EK only used this for emulsion making in the most critical instances. DW was used to mix some solutions and tap water was used for things that were not sensitive to calcium or heavy metals.

PE

Hi PE,
I am sorry but I have to respectfully disagree with you. I understand you background, but having worked in the analytical industry and working with equipment that looked for levels of inorganics(metals including sodium,calcium,etc,etc)down to ppt levels, distillation will not remove all inorganics. Boiling will not remove all insoluble salts etc.
You need to either use reverse osmosis or ion exchange cartridges to remove them.Now I am sure that for the levels photography would be bothered about, distillation would be more then good enough.
In the UK, things like DW are not so easy for 'joe public' to get now. It is thought that you must be making bombs if you want anything 'chemistry like' at all!!
BUT I am not wanting to get into a discussion as which method is better. For photography, I would settle for some DW. In the UK a lot of labs went over to DI rather then DW because of allsorts of problems from owning a still and inspections etc. It was just easier to buy bulk from people like BDH.
Alan

Photo Engineer · Jul 30, 2012

If you insist on DI water try here: http://www.culliganmatrixsolutions....eionization/?gclid=CJai_O2owrECFYNx4AodvAMABg

This is one of many companies that sell the mixed bed ion exchange resins and kits so you can do it yourself at home.

Making the resins require a quite sophisticated organic lab and lots of energy to make and then to "reclaim" after use unless they are just dumped. The resin looks like light sand before use and dark sand after use. You really must have a mixed bed of 3 types, anionic, cationic and organic to properly remove everything you need to remove.

A proper unit can use sewer water as input and turn out potable water at the other end. If the organic removing resin is not used, then the organics (and odors) go through.

Do what works for you.

PE

craigclu · Jul 30, 2012

PE - I work for a large company with DI taps everywhere who makes many and varied compounds (I'm no chemist and have limited specific knowledge myself) and many formulas specify not using DI water as certain things (colloidal silica is one I can think of as I write this) won't react without free ions to trigger needed reactions. Are you willing to illuminate me/others on this a bit? I've always had a curiosity about the mechanics of this. The synthetic viscosity improvers seem to have this common attribute to them as companies move to avoid certain silica in their products. Was this ever an issue with large scale emulsion manufacturing?

Leigh B · Jul 30, 2012

Ian Grant said:
...distilled water needs energy and that's expensive outside the US.

Interesting point, and probably valid. Not something that I had considered.

- Leigh

Photo Engineer · Jul 30, 2012

Both methods require energy!

Ionc exchange works by making either R+ or R- resins. A mixed bed has both. R is a huge polymer with lots of + or - things attached. So, run in Calcium loaded water and you get Ca++ and (R-)2 and the Calcium is stuck on the resin. You could then end up with either Sulfuric Acid or Sodium Sulfate if the counter ion is Sulfate. So, you have R_ present and SO4--. This makes (R+)2 and SO4-- and so no ion gets through. But, organics go through unchanged.

So, they add a gel like nonionic resin that absorbs organics. Sometimes they use Carbon black. Either works.

Making and disposing of these resins after use is energy expensive.

Distillation boils water which then goes through a condenser where it turns from steam back to water. The Calcium Sulfate stays behind, and the organics are destroyed by the heat for the most part. After use, scale is found in the pot and this is cleaned out by treatment with hot water or a special cleaning solution that dissolves the scale. It puts back everything into the environment that was taken out. It is more friendly and less energy intensive in the long run because there is no wast to contend with except what you started with. The starting materials (Calcium Sulfate and water) are now in separate containers.

You may have government regulations and other problems to contend with, but distillation is far simpler.

PE

ic-racer · Jul 30, 2012

Based on what you have posted about the situation, I'd try to get a deionizing filter cartridge for you water filter and use some Photoflo and see how that works. We are talking about a problem here (water spots on film) that has been solved 10,000 times over with success.

Photo Engineer · Jul 30, 2012

IC;

Such a filter is quite effective. If it works for you, use it.

If you don't mind throwing away a cartridge every few weeks, then this is just fine too.

PE

salan · Jul 30, 2012

Yep thats what i will try.
Some one locally has reccomended a di filter used for marine fish. They run at around £20 and last for a lot of water, so a trip to the fish shop might be worthwhile.
PE yes the laws in the UK are often insane!!
Alan

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jovo · Jul 30, 2012

http://www.ehow.com/how_5230189_deionize-water.html

Ian Grant · Jul 30, 2012

Leigh B said:
Interesting point, and probably valid. Not something that I had considered.

- Leigh

Actually it's a no brainer here in Europe, most so called Distilled water sold in shops and garages is often de-ionised anyway. Ion exchange columns are quite cheap and there's no disposal costs (they go back for recycling/regeneration) so the cost per litre is next to nothing, distilled water in comparison is rathe expensive these days.

In the UK my water comes from two sources, local boreholes and it's very hard, or from Nth Wales very soft, we are ona boundaty so can be given either or a mixture. The local borehole watre will begin to fur up a kettle instantly, a hot bath will have scum but even a deionising filre jug is enough to give us good water.

In Turkey the local water whether from our borehole or tanker (from nearby lake) is way too hard and has a very high salt content, we live by the sea, the lak/resovoir is a silted up estuary.

Ian

Photo Engineer · Jul 30, 2012

The reaction "good resin" + "bad water" -> "bad resin" + "good water" is driven by a rapid forward chemical reaction that precipitates the impurities and allows water free of impurities to pass through. The reaction is heavily balanced to the right, and takes little or no energy to accomplish.

To reverse the reaction and regenerate the free good resin takes a great deal of energy compared to the other direction, and a lot of water and acid. This energy must come from somewhere.

At EK, we developed a wet process that produced potable water as its output. It was totally self contained with only resins as the waste product. It was a closed system once charged with the chemicals and wash water, and the only loss was through evaporation of the solutions.

It was deemed impractical and the project was left unfinished.

I have seen commercial stills here in the US. They are about the size of a digital printer. And, they can produce many gallons per day.

Your selection must be considered on long term costs, daily operation and local laws for use of stills and for the disposal of these cartridges. Don't take the advice of any one person here. Your solution should be based on what you can afford and what is legally applicable.

PE

Matthew Wagg · Jul 30, 2012

Scrape out your freezer with A plastic scraper. The ice is De ionised. Let it melt and voila

Photo Engineer · Jul 30, 2012

Not good in some cases.

Mold and mildew grow in dehumidifiers and freezers. You can see it in the black spots on the gasket on many freezers.

PE

Diapositivo · Jul 31, 2012

Some people get the condensation water of the air conditioner and filters it with aquarium filters. Considering the small quantities involved if it is used only for the final rinse, the industrial produce is probably a safer choice.

If one's tap water is so bad that one must use alternative water for all baths, I wouldn't rule out cheap bottled water which can be very, very cheap, for the six baths and then deionised water for the final rinse.

Ian Grant · Jul 31, 2012

At one time manufacturers recommended boiling water and letting it cool and settle, fitering if needed, this would remove the worst of the hardness from the water and make a significant differance.

Sometimes wetting agent alone isn't sufficient and boiled water would be better when no deionised water is available.

Ian

nworth · Jul 31, 2012

Photo Engineer said:
As I said, use distilled!!!!! It is less expensive and is perfectly fine.

Using DI water instead of DW is like using a cannon to shoot gnats.

The only thing worse (more expensive and uselessly so) would be to use DI DW. That is way overkill.

Use Distilled Water. Here it is less than $1 / gallon. You can even buy small stills to make it yourself.

PE

There are various grades of both distilled and deionized water. Simple, single distilled water is made in large quantities in many urban areas and is, indeed, cheap. Triple distilled water using tin condensers is used in some chemical and electronic processes and is very expensive. An elaborate deionization and filtration setup can produce water of about the same quality as triple distilled at a somewhat lower cost. A simple deionizing scheme can produce decently pure water at a cost only slightly higher than distillation and at a significantly lower hardware and setup cost. For very small scale water purification, deionization is usually the way to go.

Photo Engineer · Jul 31, 2012

nworth said:
There are various grades of both distilled and deionized water. Simple, single distilled water is made in large quantities in many urban areas and is, indeed, cheap. Triple distilled water using tin condensers is used in some chemical and electronic processes and is very expensive. An elaborate deionization and filtration setup can produce water of about the same quality as triple distilled at a somewhat lower cost. A simple deionizing scheme can produce decently pure water at a cost only slightly higher than distillation and at a significantly lower hardware and setup cost. For very small scale water purification, deionization is usually the way to go.

Home stills are quite common, http://homedistiller.org/equip/photos-sold

Although the above are reflux stills in most cases, intended for alcohol, there are many others for water: http://www.jenconsusa.com/10-Water-Stills/140-4000X-and-8000X/Autostill-4000X.html and if you look at the dimensions you will see how small these are.

I am not advocating any method, just stating the fact that you can use either, and that there are advantages and disadvantages to both methods (distillation or deionization).

The bottom line is that all commercial developers and fixers are designed to work with tap water. They contain ingredients that prevent particulate matter from forming from hard water. And so, a true test is to mix some developer with tap water and look for the formation of sediment. I know that that is a harsh way to test due to expense if the test fails, but then it does work.

I don't use DW myself for mixing anything but materials for emulsion making. At EK, I did the same. We had tap water to use to test formulas with. And, what I have said goes for both color and B&W.

PE

salan · Jul 31, 2012

I thank everyone for their input, but I think I have my answers and this thread has run it's course.
Alan

Gerald C Koch · Aug 3, 2012

Ian Grant said:
At one time manufacturers recommended boiling water and letting it cool and settle, fitering if needed, this would remove the worst of the hardness from the water and make a significant differance.

Yes, the are two types of hardness; temporary hardness and permanent hardness. The temporary hardness is from calcium bicarbonate formed from water containing dissolved carbon dioxide flowing over limestone.

H2O + CO2 + CaCO3 ---> Ca(HCO3)2

Boiling the water reverses the above reaction and the resultant calcium carbonate which is insoluble will settle out. The permanent hardness is from various magnesium salts such as magnesium chloride in the water and they are unaffected by boiling. However, the permanent hardness is usually not a problem for photographers.

Bring the water to a full rolling boil for 5 to 10 minutes in an uncovered container of glass, stainless steel, or agate ware. Cover and allow it to cool overnight. Decant or filter off the softened water.

RalphLambrecht · Aug 3, 2012

i'd use britta-filtered water to eliminate calciumdeposits and 0.5g/l of edta(photo calgon)if that is not good enough.works wonders to make good tea too. the latter being an opportunity to share the expense.

finding it hard to get deionised water!

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