Calgon is Not Sodium Hexametaphosphate

gainer · Feb 14, 2005

psvensson said:
Thanks, Tom! I guess it doesn't look like a stretch to imagine that the citrate chelates silver.

The Calgon I used is of recent make. It says that it contains no phosphorous.

Here's the formula I used:

2 tbsp Diamond kosher salt
1/2 tsp Arm & Hammer Washing Soda
8 ml Calgon
2 g ascorbic acid
5 ml phenidone 1% in rubbing alcohol
1l water

Develops Tri-X in about 10 mins at 71F. It gives fairly fine-grained results, but not as fine as one that uses sulfite instead of salt.

The amount of Calgon appears to be close to the minimum: if I halve it, I start get dichroic fog.

The fact that you gave the amount of Calgon in ml made me wonder, belatedly, if you were using the liquid Calgon. I finally looked up the manufacturer's MSDS and found that the liquid and powder are different. The liquid lists only sodium hydroxide (5-10%) and citric acid (8-10%) as ingredients which leads me to believe it is mostly a solution of the trisodium citrate. 8 ml of that would hardly change the pH of a liter of most developers we use. I still don't see how or how much it could restrain chemical fog. Dichroic fog is IIRC a matter of a mirror-like coating of silver by a process akin to physical development, but not selective. Maybe it could prevent that.

psvensson · Feb 14, 2005

The fog I get from the chloride developer looks quite distinct from regular fog caused by overdevelopment or a high-pH developer. For one thing, it's rust brown. Secondly, it's splotchy and uneven, concentrated at the edges and around the sprocket holes. It has a 'smoky' appearance. I believe I've seen a sheen of another color on it too, but the samples I've kept don't seem to show it. Maybe I saw it when wet. Try the developer and I think you'll see what I mean!

Yep, I used the liquid, phosphate-free Calgon.

gainer · Feb 14, 2005

Check out the Kosher salt. Kosher does not always mean chemically pure. It could be a natural product with some chemical impurities that are not considered food impurities. The reason I'm suggesting this is that I have used that formula many times without salt with no sign of dichroic fog. I have played with non-iodized canning salt as well as with pure sodium chloride with no dichroic fog.

psvensson · Feb 14, 2005

Quite possible. I'll see if I can find some other make of salt. But Anchell & Troop mentions salt as a source of dichroic fog in pre-X Microdol, and one would think Kodak could eliminate any significant impurities.

The other possibility is that there's something in my water that produces fog in combination with the chloride.

gainer · Feb 14, 2005

Are we sure that pre-x Microdol did not have a thiocyanate in it? NaCl is a solvent of the silver halides, but it did not produce dichroic fog when I used 100 g/l along with the 100 g/l of sulfite in D-23. That's an experiment you could do in your spare time: mix up a batch of D-23 and add 50 to 100 grams of the Kosher salt to it. Or get some Morton's canning salt and use it in place of the Kosher salt in the formula that gave you the problem. Mind you, I'm not in favor of using the salt just to get finer grain, because what I saw was a little bit hazy when I used enough to do anything. It did not seem to improve the acutance, and showed loss of resolution to boot.

gainer · Feb 15, 2005

I did a little research in the CRC Handbook. You can make a liter of Calgon liquid with 50 grams of Red Devil lye and 80 grams of citric acid. The result is a solution of trisodium citrate. The degree of hydration is not a factor unless you want to evaporate the water of solution to get a powder. If you did, you would get the dihydrate, which you would then put into solution anyway. If I wander, it's because it is 5 AM here.

dancqu · Feb 15, 2005

psvensson said:
... it's splotchy and uneven, concentrated at
the edges and around the sprocket holes.

Uneven fog. Your developer may be a very sensitive
indicator of uneven development. Might even be a good
thing to work with it a while with that in mind.

My opinion; developer fog, and trisodium citrate has
been found to be an anti-fog agent. Congratulations!
I'm glad I played a roll in helping to bring it to the fore.

Have you tried it on print paper? I think doing so may
be a quick way to reveal more of it's and your
developer's properties.

edz · Feb 15, 2005

gainer said:
Check out the Kosher salt. Kosher does not always mean chemically pure.

Kosher never means chemically pure but of consistence with the interpretation of kashruth as "fit for consumption" within the Jewish code of law. Kosher does not even mean the same thing to everyone, even orthodox adherents and there are nearly as many schools of thought as Jews. Much on the market called "Kosher" is not even kosher by even the most liberal Heschers or certifying bodies--- "Kosher" is not a protected word, only trademarks like O-U, so the USPTO, WIPO or any other body can't help one before the courts (and who given that there are is hierarchy only some political leaders such as the Chief Rabbi in some countries) stop someone from calling their bacon kosher There is, of course, the Beth Din or Jewish Courts but one is only under its jurisdiction if one considers oneself under their jurisdiction...

It could be a natural product with some chemical impurities that are not considered food impurities.

What is called "Kosher salt" in the United States is hardly a "kosher" salt as all salt is Kosher--- for that matter is irrevelevant--- but is a common name for a form of salt (large crystal) used in the process for the kosherization of meats (the pragmatic removal of traces of blood since the consumption of blood is forbidden by Halacha or Jewish law).

Chemical or food impurities, btw., are irrevelant as long as one does not know of them. (information threshold).... But as soon as one ....

psvensson · Feb 15, 2005

dancqu said:
Uneven fog. Your developer may be a very sensitive
indicator of uneven development.

Ah, but image development is not uneven. Only the fog.

glbeas · Feb 15, 2005

psvensson said:
Ah, but image development is not uneven. Only the fog.

Your description is very clearly of dichroic fog and related chemical sedimentation. It's possible to wipe it off, and I've heard from another member of using some other chemical to dissolve it, what it was escapes me though.
Sounds like a ph problem, eh?

dancqu · Feb 15, 2005

psvensson said:
Ah, but image development is not
uneven. Only the fog.

Better yet I'd think as an indicator of process technique.
When there is fog does it appear evenly over the image
area and yet as you described, unevenly at edge
and sprocket areas?

I've not the fogiest why the Calgon citrate version
reduces fog. Perhaps the other chemicals in your
brew make it so.

As a move to reduce the number of variables
involved, distilled water and trisodium citrate
itself should be used. Dan

gainer · Feb 17, 2005

Just for fun, got to www.chemistrystore.com and see what they have to say about the uses of citric acid. You'll probably want to buy some. It is apparently useful in some way for keeping heavy metals from interfering with some processes. They didn't even mention its use as a stop bath.

Ryuji · Feb 17, 2005

gainer said:
Just for fun, got to www.chemistrystore.com and see what they have to say about the uses of citric acid. You'll probably want to buy some. It is apparently useful in some way for keeping heavy metals from interfering with some processes. They didn't even mention its use as a stop bath.

Citrates have poor affinity and stability with heavy metals than other chelators. It is not very effective.

gainer · Feb 17, 2005

The words I should have quoted are "Used in confections and soft drinks (as a flavoring agent), in metal-cleaning compositions and in improving the stabitity of foods and other organic substances by suppressing deleterious actions of dissolved metal salts."

I didn't have much success with citrate as a chelating agent for the calcium and magnesium in my well water. Tetra sodium EDTA is much better. But just think of the fun I can have making fizzy drinks and non-stink stop bath.

lee · Feb 17, 2005

I use citric acid for stop bath and it seems fine to me.

lee\c

psvensson · Feb 17, 2005

gainer said:
NaCl is a solvent of the silver halides, but it did not produce dichroic fog when I used 100 g/l along with the 100 g/l of sulfite in D-23. That's an experiment you could do in your spare time: mix up a batch of D-23 and add 50 to 100 grams of the Kosher salt to it. Or get some Morton's canning salt and use it in place of the Kosher salt in the formula that gave you the problem. Mind you, I'm not in favor of using the salt just to get finer grain, because what I saw was a little bit hazy when I used enough to do anything. It did not seem to improve the acutance, and showed loss of resolution to boot.

The grain I got didn't look too bad: it was less blurred-together than I would have gotten with an equivalent amount of sulfite. Accutance was OK, but not exceptional. I tried using borax instead of carbonate. That just looked unsharp.

Calgon is Not Sodium Hexametaphosphate

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