When mixing B&W chems: distilled/rev osmosis water or not? Other rants too.

Stoo Batchelor · Mar 15, 2008

markbb said:
markbb said:

Mainly because the only reasonable source of distilled water I've found is Halfords (car parts shop for non UK people) in 5 litre bottles & they don't always have it.[/QUOT

Click to expand...

Mark

Try your local aquatic centre. Most will have a reverse osmosis unit for the fish tanks. Mine sells it for, and I am going by memory, 75p for 5ltr.

Best

Stoo

Photo Engineer · Mar 15, 2008

I've been studying RO units for my emulsion work and have found from experience that all of them have suggested operating temperatures and pressures. If you exceed either one, you run the risk of either having it fail or having it perforate outright. The normal pressure range is about 40 - 80 PSI and the temperature range is about 65F - 85F. Look up your specific filter for the range, otherwise you will suffer from degraded performance or failure.

Also, if the unit begins to plug or fill, it begins to fail.

You may even begin having leaks from the RO unit itself.

PE

Stoo Batchelor · Mar 15, 2008

P.E

Thanks for that info. I am sure that I should be o.k. My unit is a tiny undersink thing, found here; http://www.thinkh2o.co.uk/products/aqua5.html The bottle fills from the mains. Inside is a clapsable bag. As the tank empties the bag expands and pushes the water out through the tap. It just trickles at a rate of about 1 1/2 ltr a minute. Hardly any use in a large darkroom etc, but I am sure safe enough for me. I store 15 litres and keep them to hand.

Cheers

Stoo

Photo Engineer · Mar 15, 2008

If you want to see what I'm talking about, Spectra Pure presents some data.

Here is just one tiny reference:

http://www.spectrapure.com/St_replac_p3.htm#spec

It shows you some of the various forms. There are many pages of specs and test equipment here at SP.

PE

Dave Miller · Mar 15, 2008

markbb said:
Mainly because the only reasonable source of distilled water I've found is Halfords (car parts shop for non UK people) in 5 litre bottles & they don't always have it.

You're lucky, my Halford's don't know what distilled water is; for that reason I use a Brita jug water filter to get the junk out of my tap water. I use this to mix my developer, and for the final rinse and find this leaves my film mark free without the addition of Photoflow or similar.

Stoo Batchelor · Mar 15, 2008

Photo Engineer said:
Photo Engineer said:

If you want to see what I'm talking about, Spectra Pure presents some data.

Here is just one tiny reference:

http://www.spectrapure.com/St_replac_p3.htm#spec

It shows you some of the various forms. There are many pages of specs and test equipment here at SP.

PE

Click to expand...

Thank You

I was not aware of any potential hazards. I will study that with interest.

Best

Stoo

Photo Engineer · Mar 15, 2008

Stoo;

Forgive me for giving a wrong impression. There are no hazards per-se except perhaps for water on the floor, but there are limits to what these devices can stand and what they can deliver under certain conditions.

PE

Paul Verizzo · Mar 15, 2008

Brita only removes chlorine and "odor."

dpurdy said:
I use water filtered through a Brita filter since we use it for drinking water anyway. I have used tap water for anything and everything and never had a problem I was aware of, but then the water quality is very high here.

Charcoal absorbant filters do nothing for salts. Chlorine and even hydrogen sulfide, in the quantities present, don't effect photo chemicals. But salts could. Could.

Oh yeah, Brita's are rather minimal for what they do. Too little charcoal, too fast a through put. I was once the filter products manager for a large industrial supply and manufacturer. Duh bigger duh better. Not hypothetical, really.

As I said on an earlier post about distilled water, I do NOT understand why people don't use it for developer and Photo-Flo, at the least. My lord, is a $1 gallon so much? That's what, four gallons for the price of a roll of Tri-X? Collecting from roofs and A/C units, filtering, boiling, AAAAAARG! $1 a gallon!

Photo Engineer · Mar 15, 2008

Paul;

I have run tests on tap water vs distilled vs DI, vs DI/dist H20. With most films and papers the prevalent Ion is chloride and it has little effect on paper and no effect on film. The second prevalent ion is Calcium and it is taken care of by the sequestrants in the formula. Ozone for the most part has little effect.

PE

Dave Miller · Mar 16, 2008

I think its very easy to get paranoid over water quality. I use a domestic water filter to take out the fine partials such as calcium that otherwise occasionally turn up on one of my films. The dissolved chemicals are not a problem for me. I have Photoflow and have used it in the past, but cannot find any difference between using it in the filtered water, or using filtered water on its own, so I no longer use it. I must add that I live in a medium/hard water area where the incoming water is treated to drinking water standards, and is, I find quite palatable.

Paul Verizzo · Mar 16, 2008

Photo Engineer said:
Paul;

I have run tests on tap water vs distilled vs DI, vs DI/dist H20. With most films and papers the prevalent Ion is chloride and it has little effect on paper and no effect on film. The second prevalent ion is Calcium and it is taken care of by the sequestrants in the formula. Ozone for the most part has little effect.

PE

Thanks for that very specific information, PE.

Of course, most homebrews don't use sequestrants. Distilled water takes care of that, of course.

Photo Engineer · Mar 16, 2008

Yes, certainly.

However, I keep a handy dandy bottle of DiSodium EDTA on the shelf for homebrews, or I filter the mix if it looks cloudy.

PE

Stephanie Brim · Mar 16, 2008

My problem is lime. I've tried multiple things to get streaks of deposits off my film and have had no luck. I'm going to have to move to an all distilled water workflow again. It sucks.

walter23 · Mar 16, 2008

Bobby Ironsights said:
I think you mean additive mark, and it's a lost cause. Adding more crap to your water will not make beads of water dry without leaving the mineral deposits behind.

Those compounds just don't evaporate.

You could use photoflo (a wetting agent) and then just squeegee them off, but it's not really all that different from just squeegee'ing them off in the first place and you can damage delicate emulsions.

You're right, but wetting agent (some kind of surfactant) reduces the surface tension of the water and allows it to more easily flow off the surface of your film. If I get a calcium stain, it will be in the lower corner of my film (if I neglect to dab the final drop off with a sleeve of my shirt).

Think of it as an extremely effective squeegee that doesn't run you the risk of damaging your emulsion. Without it, water beads up in various spots and evaporates slowly from those droplets, leaving all the impurities behind. With it, the surface tension is reduced so the water doesn't bead up, and the water neatly sheets off the film taking most of the impurities (all the visible ones, in my experience) with it.

I use Edwal LFN wetting agent. Comes in a tiny little bottle and one drop to the final wash works wonders.

Paul Verizzo · Mar 16, 2008

"It sucks?"

Stephanie Brim said:
My problem is lime. I've tried multiple things to get streaks of deposits off my film and have had no luck. I'm going to have to move to an all distilled water workflow again. It sucks.

Correcting a major water problem for $1-1.25 a gallon is NOT suck. Too bad every ailment in life couldn't be perfectly corrected for so little.

Celebrate!

Stephanie Brim · Mar 16, 2008

Well, what sucks is the storing of the gallons. Small house. Once I start printing, I'm going to be really screwed.

Paul Verizzo · Mar 16, 2008

Ah, yes....

Stephanie Brim said:
Well, what sucks is the storing of the gallons. Small house. Once I start printing, I'm going to be really screwed.

I feel your pain. I lived in a 429 sf house (with cat) for six years. I stored a LOT of things outside.

fschifano · Mar 16, 2008

Stephanie Brim said:
My problem is lime. I've tried multiple things to get streaks of deposits off my film and have had no luck. I'm going to have to move to an all distilled water workflow again. It sucks.

You needn't use distilled water for everything, just the final rinse for film only. I'd recommend some sort of wetting agent anyway, be it Kodak's PhotoFlo or Edwal's LFN. Calcium, or lime, is pretty well handled by the sequestrants in commercially prepared chemistry or with the addition of Sodium EDTA to homebrew stuff as recommended by PE.

Stephanie Brim · Mar 16, 2008

Apparently not MY lime. It appears to be some kind of stubborn variety that a good wetting agent can't even get rid of.

I tried a distilled water rinse with a last bath of PhotoFlo mixed in distilled water and still got spots. The only thing that's worked without hitch for me was when I used a fully distilled water work flow. So...back to buying water I go.

Removed Account · Mar 16, 2008

Photo Engineer said:
BTW, what do you do to keep your tea from forming scum in London? Or your beer? Actually, I enjoy a warm pint at the White Harte on Drury Lane and a good cuppa.

PE

Does the muffin man happen to drink there too?

Photo Engineer · Mar 16, 2008

No, but Sir Arthur Clarke used to.

PE

Bobby Ironsights · Mar 17, 2008

Stephanie Brim said:
I tried a distilled water rinse with a last bath of PhotoFlo mixed in distilled water and still got spots. The only thing that's worked without hitch for me was when I used a fully distilled water work flow. So...back to buying water I go.

I get spots when I use photoflo in my distilled too. So I just use distilled.

Also, instead of rinsing with distilled. I soak for at least five minutes. That works better for me, I still get spots when I just quickly rinse because I'm in a hurry.

markbb · Mar 17, 2008

Photo Engineer said:
.

BTW, what do you do to keep your tea from forming scum in London?

PE

Use a teapot.

When mixing B&W chems: distilled/rev osmosis water or not? Other rants too.

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