Does water quality effect the chemicals used to develop film? I am thinking in terms of minerals,hardness etc? Will a good filter take out unwanted minerals?

-- Melvin (bramley@nanaimo.ark.com), January 29, 2002

Answers

A filter won't remove dissolved minerals, and neither will one of those magnetic or RF 'water treatment' clamps that people are conned into buying.
Domestic water filter jugs remove dissolved gases and some chemical contaminants, but again, they don't really tackle the problem of water hardness. If your water is very hard, I'd suggest buying distilled water to make up your processing solutions, or using tap water that's been boiled for a few minutes.
I recommend fitting a good water filter anyway, to remove particulates from the wash water. Mesh types aren't very effective unless the mesh catches particles smaller than 5 microns. The best filters use a fibre or granule cartridge, or a permeable membrane. You might be surprised at the difference a good filter will make; especially to 35mm negs.

-- Pete Andrews (p.l.andrews@bham.ac.uk), January 30, 2002.

Unless your water is very hard, it will have little or no effect with most photo chemicals. Most developer, fixers, etc., contain sequestering agents, which lock up the mineral content, keeping it from affecting the active components. Toners are often very affected by water hardness; here it pays to use distilled water. Also, if you have high mineral content, it is a good idea to make your final wash a rinse in bottled or distilled water.

Don't try boiling water. That will actually make it harder, not softer, because you boil away the water, but not the minerals.

David Carper ILFORD Technical Service

-- David Carper (david.carper@ilford.com), January 31, 2002.

Melvin, If you and a fellow shooter shoot the same shots, same exposure ect. and he/she goes to their house to develop and you yours, it has been found that, while keeping everything the same, the negatives will be different due to the water.

-- Scott Walton (scotlynn@shore.net), February 01, 2002.

Good (and expensive) water softeners use memranes with special resins that hold all the cations in the tap water. There are devices (that use two different membranes) that can hold anions too, but they are mostly used by labs. A water softener is quite effective and helps you process your negs neatly and without stains.

-- George Papantoniou (papanton@hol.gr), February 04, 2002.

Sorry to contradict you, David, but at least one form of water hardness CAN be removed by boiling.
Water hardness can be caused by a number of dissolved minerals, but one of the most common forms of hardness is due to dissolved Calcium Carbonate and Carbon Dioxide. This is called 'temporary' hardness because the CaCO3 can be precipitated out by heating or boiling the water.

See this link for a fuller explanation.

-- Pete Andrews (p.l.andrews@bham.ac.uk), February 05, 2002.