De-ionized water: safe for photo use?

Alessandro Serrao said:

Good point.
Why Kodak doesn't suggest to use distilled water only?

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DUH! Could it be because it is not necessary?

I use distilled whenever I mix chemistry, and I use it for final wash (along with Photo Flo).
The advantage/my reason for doing so is that it doesn't have the dissolved minerals/dirt/permissible levels of toxic refinery runoff that the tap water has in it, so it eliminates a consistency-obstructing variable. When I lived in North Texas, our tap water came from a lake, so the dissolved solids profile would change radically throughout the year.
I don't know if it had any discernible effect on my negatives, but the more variables I have control over, the closer I am to total consistency.

okto said:

I use distilled whenever I mix chemistry, and I use it for final wash (along with Photo Flo).
The advantage/my reason for doing so is that it doesn't have the dissolved minerals/dirt/permissible levels of toxic refinery runoff that the tap water has in it, so it eliminates a consistency-obstructing variable. When I lived in North Texas, our tap water came from a lake, so the dissolved solids profile would change radically throughout the year.
I don't know if it had any discernible effect on my negatives, but the more variables I have control over, the closer I am to total consistency.

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Actually distilled water isn't pure, it can contain organics carried over in the distillation process. Cheap ditilled water is no better than de-ionised/

If you think it's needed then you'd use water that's been deionised and then distilled. However . . . . . . . . .

fotch said:

DUH! Could it be because it is not necessary?

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And it's not necesssary to use distilled or de-ionised with tap water that meets drinking water requirements (which are quite strict in the US/Canada/Europe etc).

In Turkey our water isn't drinkable, everyone uses bottled water, at best the tap water's just about OK at worst it's from a borehole when the reservoirs are dry and the salt content etc is horrific as we are on the coast.

Manufacturers know far better than some posting here so believe them first.

Ian

It's still an incremental improvement. I don't need perfection, I need consistency.

When I mixed my fixer with tap water, I got heavy precipitates, and it would occasionally get cloudy or chunky. When I switched to distilled, those problems went away.

Certain Kodak developers were carefully buffered to accommodate "average" tap water conditions. This does not mean that their performance
is ideally predictable given that premise. Our water quality varies dramatically from city to city. It's safe to drink most places (certainly not all),
but that applies to bacterial content, not hardness or softness or degree of chlorination etc. There can also be relatively harmless particulates
in tap water that can stick to film and contaminate it. A lot also depends on how fussy you need to be regarding negative densities etc. When
in doubt, use real distilled (which by definition cannot contain organics unless there were contaminated lines or containers afterwards). It's that simple. Chemistry 101. Not rumor. Not opinion.

PS - case in point: tiny bit of mineral can come thru even with high-quality tap water which will stick to the emulsion. You might be able to
filter these out in-route, or they might come from your water heater - but even if very small might cause the chemistry to produce a little
halo around them which actually becomes a significant spotting nuisance afterwards. You might get away with tap water time after time,
and then suddenly after a major rainstorm or whatever the particulate content goes up. It could still be within legal limits for human health
standards but not so great for film. You take your chances.

okto said:

It's still an incremental improvement. I don't need perfection, I need consistency.

When I mixed my fixer with tap water, I got heavy precipitates, and it would occasionally get cloudy or chunky. When I switched to distilled, those problems went away.

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But did it still fix your film/prints?