Distilled versus demineralized water

[Edimilson]

Hello again!

I have just found out that demineralized water is a lot cheaper than distilled water around here (Rio de Janeiro). My question is: can I replace distilled water with demineralized water when mixing my developer?

Thanks a lot!
Edimilson

 

[Ian Grant]

Yes, it's a far better option. Most labs use an inline de-ionising column for de-mineralised water. There a a few threads about this subject here on APUG

Ian

 

[Photo Engineer]

Deionized or demineralized water may still contain organic impurities.

PE

 

[Edimilson]

Thanks! I thought my question was too dumb to have been asked before. I'm gonna do some research then.

 

[Anscojohn]

Is there any possibility of collecting the run-off water from someone's air conditioning unit? For years, I have used this kind of run off water, after filtering through coffee filters, to mix my developer with never a problem. I store it in large jugs and carboys during the hot weather. My indoor house plants like it, too.

 

[ElrodCod]

Deionized or demineralized water may still contain organic impurities.

PE

Not unless they were introduced after the RO process. I don't know of any organic impurities that are smaller than the mineral ions.

 

[Photo Engineer]

Not unless they were introduced after the RO process. I don't know of any organic impurities that are smaller than the mineral ions.

The demineralization process uses Anionic and Cationic resins to remove salts, but these have no effect on organics, especially neutral ones. The RO process removes minerals and organics but only up to a point and only to a specified molecular weight, and so a 20,000 D unit will pass anything under a molecular weight of 20,000 to waste but keep things above in the water. This includes most bacteria and mold.

An RO unit with activated charcoal filtration along with the RO filter will remove the organics as well.

RO units of this type are very very slow, expensive and require periodic replacement of both filters. I've been researching them all for emulsion making and have a lot of files and references.

PE

 

[Photo Engineer]

Is there any possibility of collecting the run-off water from someone's air conditioning unit? For years, I have used this kind of run off water, after filtering through coffee filters, to mix my developer with never a problem. I store it in large jugs and carboys during the hot weather. My indoor house plants like it, too.

Do not use this water. It is dirty, dusty and filled with mold spores and bacteria. This is a rather common question here, you may want to look up others comments as well.

PE

 

[dancqu]

Most labs use an inline de-ionising column ... Ian

Column? Have not by chance ion-exchange in mind?
Perhaps Reverse Osmosis? Dan

 

[Paul Verizzo]

Is there any possibility of collecting the run-off water from someone's air conditioning unit? For years, I have used this kind of run off water, after filtering through coffee filters, to mix my developer with never a problem. I store it in large jugs and carboys during the hot weather. My indoor house plants like it, too.

Tap water in most places will be better than A/C water. Think about it, dust and pollens that get past the air filter will be captured by the moisture on the evaporator coils. Then, as they wend their way out, more dirt and crud and the living things start to multiply.

Because my evaporator is about 25 feet from the outside, my condensate tube plugs up about three times a season and I need to blow it out with compressed air.

As I've said everytime this topic has come up, how anyone can justify such antics when every grocery store in America has Purified, Drinking, or Distilled Water for around $1 a gallon is beyond me.

This topic is truly Lazarus like.

 

[Anscojohn]

Well, I guess Lazarus and I are very lucky. I have used filtered AC water, heated in the microwave, for more than twenty years to mix my developer. I am fortunate, I guess, in many ways. Because of the position of my central AC unit and the absence of a floor drain, the installers had to run the condensate line into the stainless steel sink where I wash my film and paper. All I have to do is put something there to catch the water. Call me cheap; whatever; but lugging gallons of water in plastic jugs home from the supermarket appeals to me not.

 

[Photo Engineer]

Well, I guess Lazarus and I are very lucky. I have used filtered AC water, heated in the microwave, for more than twenty years to mix my developer. I am fortunate, I guess, in many ways. Because of the position of my central AC unit and the absence of a floor drain, the installers had to run the condensate line into the stainless steel sink where I wash my film and paper. All I have to do is put something there to catch the water. Call me cheap; whatever; but lugging gallons of water in plastic jugs home from the supermarket appeals to me not.

Usually mold and fungi grow on the condenser coils of AC and dehumidifier units and these spores play hell with gelatin. That is one major problem. The other is that the tiny spores can show up as tiny dots in magnified enlarged images.

So, we were always taught not to do this. In fact, we were also taught not to give this type of water to pets, as it could cause severe infections of mold and fungi.

I say "use what works for you", but I have never used AC or DH water in any way photographically. Best of luck.

PE

 

[Paul Verizzo]

Not to be polemical here,

Well, I guess Lazarus and I are very lucky. I have used filtered AC water, heated in the microwave, for more than twenty years to mix my developer. I am fortunate, I guess, in many ways. Because of the position of my central AC unit and the absence of a floor drain, the installers had to run the condensate line into the stainless steel sink where I wash my film and paper. All I have to do is put something there to catch the water. Call me cheap; whatever; but lugging gallons of water in plastic jugs home from the suermarket appeals to me not.

But how can you heat that water hot enough in a microwave to kill the organisms? Boil, sure.

Hauling 8 pound jugs into the house is how I keep my perfect body, well, perfect. And some PBR .....

 

[BBMOR]

hey
sorry to say but a mixed bed (a cat/anion mix of IX) is removing quite wel organics ,MB are used after RO in the microwafers industry,the removal is so good that the anionic resin is blocked and does not work properly ,i know this quite well because of my job ,for more than 30 years i work for one of the largest IX producers world wide and TOC(organics as well as NOM is one of the issues in water treatment )
for normal use,for diluting and disolving photografic solutions ,high top quality water even is not good because all the formulations contain some additives (complexing agents and so on) preventing all kinds of problems

jm

 

[Photo Engineer]

When I used mixed bed anionic and cationic resins, the organics got through. I had to use either a special neutral resin or activated charcoal to remove organics. That is the reason for my comments above. In particular, no resin will remove bacteria or spores. RO will do this job though.

The problem, as we evaluated this at EK was the cost to the average individual. On a mass production scale, RO and distillation became quite economical at that time, and now distillation has become much less expensive. RO has also dropped in price, but remains rather slow for some applications.

PE

 

[Monophoto]

Obviously, the quality of tap water varies considerably. I've been to Rio, but my practice when traveling outside the US is to only drink liquids that come in bottles, so I can't comment on the tap water there.

Here in upstate NY, tap water is good enough to use with no further treatment. We happen to have a water softener in our home, but in a previous home I used unsoftened tap water to mix developer with no adverse consequences.

I do, however, use treated water for the final rinse (with highly diluted PhotoFlo). When I first started in the darkroom, I used water collected from a basement dehumidifier that I then filtered to remove dust and particulates. But I would agree with PE that there was a risk of stuff growing in that water, so I used a special collection container that I rinsed with a hypochlorite bleach solution between uses.

Today, we have a RO 'drinking water system' in our kitchen, and not only does the coffee taste much better, it provides a source of treated water for that final rinse. Yes, the filters have to be replaced annually but that's not a very big deal.

 

[dancqu]

RO has also dropped in price, but remains
rather slow for some applications. PE

I think of RO as a remover of organic and particulate
matter while ion exchange is a remover of at least the
common mineral components of hard water.
Is my thinking correct? Dan

 

[Photo Engineer]

Dan;

Huge RO units are used for desalinization of seawater in desert countries, where stacks of cylinders are used. In goes sea water, out comes fresh water (with organics) from one port and out comes brine from the other. Of course, an active carbon stack removes the organics, bacterial and mold. There are some photos of this on the various large scale RO web sites. Of course UF can be used as well.

PE

 

[Anscojohn]

But how can you heat that water hot enough in a microwave to kill the organisms? Boil, sure.

Hauling 8 pound jugs into the house is how I keep my perfect body, well, perfect. And some PBR .....

Paul,
Well, I have arthritis and am no stoic, so the less lugging, the better for me.
I heat the water to the temp needed for mixing; that is all. In the rare cases where I do not have AC water--I use it on my house plants, as well--I just boil and filter my tap water, like ye olde lab rats who taught me darkroom half a century ago. But my modern experts tell me that's not good enough; as well; then I read in the paper about some of the stuff sold in the super markets as distilled water (in plastic jugs, of course).
Mebbe I should start boiling and filtering my AC water.......
As Photo Engineer so correctly points out, "if it works for you......." Admitedly, my developer photo chemistry is pretty simple; D23; DK25R. Ansco 103; occasionally LPD, and Rodinal. Ordinarilly I use tap water for my F-24 fixer.

 

[ampguy]

interesting

But keep in mind that the RO water removes the salts from the softener water, and that salts in water may be good for some processes. I think photo flo or some other b/w chemicals have high salt content.

Obviously, the quality of tap water varies considerably. I've been to Rio, but my practice when traveling outside the US is to only drink liquids that come in bottles, so I can't comment on the tap water there.

Here in upstate NY, tap water is good enough to use with no further treatment. We happen to have a water softener in our home, but in a previous home I used unsoftened tap water to mix developer with no adverse consequences.

I do, however, use treated water for the final rinse (with highly diluted PhotoFlo). When I first started in the darkroom, I used water collected from a basement dehumidifier that I then filtered to remove dust and particulates. But I would agree with PE that there was a risk of stuff growing in that water, so I used a special collection container that I rinsed with a hypochlorite bleach solution between uses.

Today, we have a RO 'drinking water system' in our kitchen, and not only does the coffee taste much better, it provides a source of treated water for that final rinse. Yes, the filters have to be replaced annually but that's not a very big deal.

 

[ampguy]

I'd agree

I think tap water, filtered through charcoal (pur or brita) is usually fine for b/w developing. If you have a $20 TDS tester, having TDS of < 200 or so should be fine (in the US, distilled water is TDS of 3 or less).

Boiling won't hurt, but I wonder if it has much effect for darkroom use?

Paul,
Well, I have arthritis and am no stoic, so the less lugging, the better for me.
I heat the water to the temp needed for mixing; that is all. In the rare cases where I do not have AC water--I use it on my house plants, as well--I just boil and filter my tap water, like ye olde lab rats who taught me darkroom half a century ago. But my modern experts tell me that's not good enough; as well; then I read in the paper about some of the stuff sold in the super markets as distilled water (in plastic jugs, of course).
Mebbe I should start boiling and filtering my AC water.......
As Photo Engineer so correctly points out, "if it works for you......." Admitedly, my developer photo chemistry is pretty simple; D23; DK25R. Ansco 103; occasionally LPD, and Rodinal. Ordinarilly I use tap water for my F-24 fixer.

 

[Anscojohn]

Ampguy,
Well, all I know is what the old f..rtz, who had been working in darkrooms since the 1930s, taught me in the early 1960s. One of the standbuys was water, boiled in a stainless steel pot, then filtered. They always said that boiling the water made the developer last longer. I always ASS u ME d the boiling drove off some of the air.
I just think that nowadays, people seem to want to complexify things with all this discussion of distilled, deionized, dephlogistrated (vbg) water.
I guess if I really were concerned that my AC water had all that mold, fungus, and rot, boiling it would solve that problem. But as I have said before, I have been using filtered AC water since I first had an easy way to capture it. I store it in large plastic carboys and also in five gallon stainless photo chemical tanks.
If it works, don't fix it, sez I to mesself, sez I.

 

[ampguy]

ok, sounds good to me

If it's working well, keep doing it!

Ampguy,
Well, all I know is what the old f..rtz, who had been working in darkrooms since the 1930s, taught me in the early 1960s. One of the standbuys was water, boiled in a stainless steel pot, then filtered. They always said that boiling the water made the developer last longer. I always ASS u ME d the boiling drove off some of the air.
I just think that nowadays, people seem to want to complexify things with all this discussion of distilled, deionized, dephlogistrated (vbg) water.
I guess if I really were concerned that my AC water had all that mold, fungus, and rot, boiling it would solve that problem. But as I have said before, I have been using filtered AC water since I first had an easy way to capture it. I store it in large plastic carboys and also in five gallon stainless photo chemical tanks.
If it works, don't fix it, sez I to mesself, sez I.