Distilled compared to filtered water

[Kirk Keyes]

Suitable? One that is very popular in environmental labs is the Millipore Milli-Q system. http://www.millipore.com/catalogue/module/c7658. It's very compact. But it is slow - about a gallon in 10 minutes or so if I remember right. But that's fine for a small lab. About $2000+ or so depending on model. Dead Link Removed Several on ebay right now

 

[Harry Lime]

thanks everyone

HL

 

[Fraxinus]

As it hasn't been mentioned, I thought I would put in a word for the AQWSAFE domestic distiller unit that I recently bought to feed my Fuji Pictrography processor. The £175 investment is soon recouped if your only alternative is to buy bottled distilled water. I'm now using it to provide water for chemical mixing (and the domestic iron!) as well. It's also drinkable of course.

Interestingly, deionised water was too pure for the Fuji Pictrography processor, which relies on being able to send a small current through the water for monitoring purposes.
Details on AQWSAFE Dead Link Removed; they also sell distilled water in bottles.

 

[RobC]

Of the the three processes: Reverse Osmosis, Distillation and Deionisation, the deionisation will give the purest water which is also closest to PH7.

Water is what is called "amphiprotic" which means it reacts with itself. What that means is that if you remove the ions, which is one of the things a deionisation unit will do ( as well as removing trace elements ), it will, all by itself, become reionised to a certain extent until it reaches an equilibrium. i.e. the PH will change. PH means Power of Hydrogen ionisation. The trace elements will not reappear though so it will still be very pure water and the buffering in the developer is more than adequate to cope with the small amount of PH change due to water not being at exactly PH7.

So having deionised your water, if you let it stand for a day or two, its PH will change and may well become useable by your processor, but maybe not depending on its sensitivity.

 

[RobertP]

PE, I had a Kinetico GX Plus Deluxe system installed. It has a 20 Gallon holding tank. I'd have to check but I think it was around 1300.00 for the complete installation. That included plumbing to the upstairs kitchen sink, darkroom sink and even to the ice-maker on the fridge. All other water running to the darkroom sink is run through micron filters. Robert

 

[RobertP]

PE. I think Kinetico is sold through Clearwater Systems. We have a distributor here locally and their service has been very good. Robert

 

[Curt]

This is a great thread. I live in Northwestern Washington State and have never gotten around to putting in a water filter. I have used distilled water but for the most part I have not used filtered water for BW processing. The water here is apparently very very clean and pure, as it goes. When I went to school in California I went to the grocery store and got water there from a machine. It seemed pretty weird to have to get water from a machine but you couldn't drink the tap water let alone use it for photo developing.

Does anyone else use unfiltered water and where do you live? What about BC and Vancouver Island?

Curt

 

[Andrey]

Of the the three processes: Reverse Osmosis, Distillation and Deionisation, the deionisation will give the purest water which is also closest to PH7.

Water is what is called "amphiprotic" which means it reacts with itself. What that means is that if you remove the ions, which is one of the things a deionisation unit will do ( as well as removing trace elements ), it will, all by itself, become reionised to a certain extent until it reaches an equilibrium. i.e. the PH will change. PH means Power of Hydrogen ionisation. The trace elements will not reappear though so it will still be very pure water and the buffering in the developer is more than adequate to cope with the small amount of PH change due to water not being at exactly PH7.

So having deionised your water, if you let it stand for a day or two, its PH will change and may well become useable by your processor, but maybe not depending on its sensitivity.

pH won't change just because the water is standing by itself. And pH stands for "hydrogen potential"

A singly distilled water is perfectly fine for any photographic purpose. Virtually all of the metal ions are removed. The conductivity might be a bit lower due to CO2, H2S and NH3 or other ionised gases present, but they play little difference in chemistry.

Deionization won't remove particulate matter and won't remove organic compounds.

Also, I would expect Kodak and others to anticipate the problem of the running water. They will add EDTA and/or other chelating agents which will bind divalent cations like magnesium++ and calcium++.

EDTA is in your shampoo and mayonaise. It is in the photochemistry as well and allows you to use "bad water"

 

[Andrey]

Here's what a guy whose job it is to deliver pure water to a biotech lab has to say:

as the names imply deionized water is water
that has been passed through a column or membrane to remove ions present. If
it is of the type used in homes, it is not truly a de-ionizer, removing all
ions, but rather an ion exchange column that exchanges polyvalent ions such
as Mg++ and Ca++ for Na+ ions. A de-ionizing column will not remove nonionic
organic substances from the water.

In contrast, distilled water is actually boiled in a still and the
condensate collected and distributed. Distillation removes both ionic and
nonionic organic contaminants.

Either method will require periodic regeneration, in the case of a
deionizer, or cleaning in the case of a still. I think you will have to
weigh the cost of maintenance and the required capacity needed before making
your decision.

 

[Photo Engineer]

Robert;

Thanks for the answer. I'm still looking as there are problems with most systems.

As for distilled water, it can still contain volatile organic materials and any metal salts carried in by the distillation recover and condensation equipment. Typically, alcohols and other volatiles along with iron or alumium (depending on the pipes in the condenser) are found in DW.

The best water is Distilled Deionized water, but who cares. DW is good enough or DI water is good enough. I never use either to mix processing chemistry. All formulas prepackaged by Kodak contain sequestrants to remove harmful products in most water supplies. In fact, D-72 is Dektol but without the extra sequestrants.

I do use DW for emulsion making.

PE

 

[Andrey]

In fact, D-72 is Dektol but without the extra sequestrants.

I just wanted to ask about that, actually.

In the club I've been going to I used D-76 and D-72. I couldn't find D-72 in the store, and I was wondering why.

Basically
D-72 + chelating agents = Dektol?

Where would they (the club) get the D72 then?

 

[Photo Engineer]

D-72 + chelating agents and 'packing agents' = Dektol.

D-72 is the published scratch mix formula for Dektol and when Dektol was originally sold as 2 parts, Dektol was just D-72 + chelating agents. When Dektol converted to a 1 part powder, then there were packing agents added to protect the chemicals from each other and from oxidation. D-72 was never sold under that name. It has always been sold as Dektol. There are no sensitometric differences that I can find between the two.

PE

 

[Andrey]

Awesome. Now I get it.

Does anybody make D72 nowadays commercially or is it only made from scratch privately?

 

[Photo Engineer]

D-72 was never ever a commercial product sold under that name AFAIK. Dektol is functionally identical in every way.

PE

 

[srs5694]

Andrey, is there any particular reason you're looking for D-72 vs. Dektol? Is it just that you're curious where your club was getting something it called "D-72?" If so, they could have had somebody mixing it from scratch or just labeled their Dektol "D-72."

I wouldn't be at all surprised if somebody markets something based on the D-72 formula under a name other than "D-72" or "Dektol," much as Ilford sells something based on D-76 as "ID-11." I don't know of a specific product that fits this description, though; I'm just speculating that somebody may have done/be doing it.

 

[Andrey]

Andrey, is there any particular reason you're looking for D-72 vs. Dektol?

No reason really.

Is it just that you're curious where your club was getting something it called "D-72?"

Yes. That's the chemistry that I used, just because it was there. Now I want to keep using it, and I expected to find it on sale somewhere.

If so, they could have had somebody mixing it from scratch or just labeled their Dektol "D-72."

I wouldn't be at all surprised if somebody markets something based on the D-72 formula under a name other than "D-72" or "Dektol," much as Ilford sells something based on D-76 as "ID-11." I don't know of a specific product that fits this description, though; I'm just speculating that somebody may have done/be doing it.

Gotcha. Thanks.

 

[srs5694]

Is it just that you're curious where your club was getting something it called "D-72?"

Yes. That's the chemistry that I used, just because it was there. Now I want to keep using it, and I expected to find it on sale somewhere.

In that case, either get Kodak Dektol or learn to mix D-72 from scratch. You should get identical results either way.