Originally Posted by modafoto
And God only knows what the fish do in it!
If I had been present at the creation, I would have given some useful hints for the better arrangement of the Universe.
Alfonso the Wise, 1221-1284
That's a good idea i'll use from now on. Much cheaper than de-ionised water. The water in Bristol is so hard it almost comes out the tap in lumps! Make great tea though.
Originally Posted by Dave Miller
There are 10 types of people in this world - those who understand binary and those who don't.
Morten, In the late 60's I was refused water on a ferry to Copenhagen. They told me I could habe beer or soda vand, becasue water is what the ship was sailing in.
This statement is wrong. Hardness is defined as the combined concentration of calcium and magnesium ions in the water. Boiling will not remove these ions from water.
Originally Posted by GeorgesGiralt
Kirk - www.keyesphoto.com
So, here's a question from someone who's been doing a lot of dfilm evelopment at home and is trying to settle down his techniques to a consistent grind:
I've been using distilled water for all chemistry mixing, prewets, rinsing, etc to avoid any problems, and have had good luck with avoiding particulates on my negs, spotting, etc. However, as you can imagine, the costs of distilled water, while not earth-shattering, are also not insignificant.
I've been considering refilling my distilled bottles with filtered water from the supermarket (much cheaper), which should deal with the particulates. Is this a good/bad idea?
If I were to test either this filtered water, or my tap water, for its suitability in photographic uses, how should I test it (I'm assuming PH strips would be a good start), and what should I test for? Could taking my water to the local water authority for an analysis be a good step as well?
Sponsored Ad. (Subscribers to APUG have the option to remove this ad.)
Try using distilled in just the final wash as I mentioned above. This cleaned up the small amount of grit I had and probably cut the price by 95%.
Boiling will make some of the minerals fall out as a precipitate which can be filtered out. Possibly the ions recombine at the higher energy levels to form solids? - dunno, not a chemist, but it does happen - have a look in the bottom of your kettle. Don't know what percentage of minerals are extracted in this manner tho...
Boiling drives out oxygen and other gasses such as chlorine and whatever other gunk the authorities put in the water to make it safe to drink, and kills live organisms. Personally, I use whatever comes out the tap except for mixing stock solutions and a final film rinse, for which I use de-ionised water from the local car spares centre. Possibly if I was more concerned, I would use it for making up the working solutions and pre-soak too, but I'm not, so I don't... I did get drying marks occasionally before I started using de-ionised (+ wetting agent) for a final rinse but do not any more.
That of course explains why the pot I boil water in is always coated with white stuff. Only the molecules are removed, not the ions.
Originally Posted by Kirk Keyes
Boiling water vaporises some of it, raising the concentration of salts. Boil emough (or have hard enough water), and you get a saturated solution with some salts falling out as solids. So even if some solids are removed, the water ends up with MORE salts in it.
Originally Posted by gainer
There are also some salts that are more soluble in cold water than in hot - gypsum (calcium sulfate) is an example. Heating water with dissolved gypsum makes a lot of it fall out. Some of it can then dissolve again as the water cools...
-- Ole Tjugen, Luddite Elitist
Who would have thought that water theory would come up with so much info? Oh well, for what it's worth, I found that I only need distilled water for the final rinse. Using the distilled water in the rest of the procedure caused me to under fix my film (purple-pinkies). Using the same fix bottle with regular tap on another set of the same type of film did not result in this problem. Go figure...