Insoluable matter than cannot be filtered out well can absolutely ruin negatives by leaving small particles trapped in the emulsion.
Here's a link to Scott's Vol. II
if anyone is interested in seeing what it's like.
Well Pat, here's how you do the insoluble matter test, from the ACS book:
Dissolve 20 g in 300 ml of water, heat to boiling, and digest in a covered beaker on the steam bath for 1 hour. Filter through a tared, porous porcelain or a platinum filtering crucible, wash thoroughly, and dry at 105C. The weight of the residue should not exceed 0.0010 gram.
You've got the 20 mule team, hitch'em up and drive them to the lab.
Doesn't have anything to do with borax, but just generally speaking toward subtleties, I find it interesting how some kallitype/VanDyke Brown/Argyrotype color/tone results in the final print depend upon the humidity in the sensitized paper.
There are so many variables and variations, who really knows.
I did find an alternate source of borax for those who are happy with bulk alternative suppliers- I can't remember the exact name but it's a swimming pool product called ProTeam something, maybe ProTeam Supreme made by Haviland in Grand Rapids, MI. I intend to call them some morning when I remember & ask about purity. What will probably happen is, as PE Ron says, they'll tell me 95% and I'll have some thing to worry about.
They have a "PLUS" version, that has boric acid and fragrance. That's not the one.
Originally Posted by Murray@uptowngallery
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Well, now, is that the requirement for film developing or for some other purpose. Did you run that test to see if the borax you would use for D-76 meets the spec? Do you have someone's word that the insoluble matter in 20 grams of your borax does not exceed 0.0010 g? You're putting me on, aren't you?
Originally Posted by Kirk Keyes
I have made many lousy negatives in my time, but I can't say I ever observed that one. Over and underexposure or over or under development I have seen often, and motion blur and focus errors too, but most of my bad negatives were just not good pictures to begin with. In the old days of softer thicker emulsions I had my share of reticulation as well. I have to admit that I did not always use borax in my developers. In my days of photographing from my chair as first oboist of the Norfolk and Peninsula Symphonies, now merged into the Virginia Symphony, My favorite developer was a phenidone, hydroquinone, sulfite concoction with no other alkali.
Originally Posted by Photo Engineer
That's the requirement to meet the specifications for ACS Reagent Grade, just as I plainly stated above.
Originally Posted by gainer
Well I'm not sure if this will work, I typed it into word and am just going to paste it.
It's what is written on my bottle of reagent grade Borax.
Analytical Reagent grade Sodium Tetraborate
Na2B4O7, 10H2O = 381.43
Assay = 99.101%
Heavy Metals (as Pb) 0.001%
Hmm, the subscript numbers have all come out at the same size as the rest of the type. What I did was to underline all of the numbers which should have been subscript characters.
Last edited by Mick Fagan; 12-11-2007 at 01:32 AM. Click to view previous post history.
I finally learned how to use the Acrobat reader to search the net. 20 Mule Team Borax is the Technical grade and contains greater than 99% sodium tetraborate decahydrate. It contains no chlorine and no phosphates. 20 grams will not dissolve in 300 ml water at 20 C where the solubility is 4.71% by weight. All the good tables and curves are shown. Have a ball. I will continue to use the cheap stuff for anything I'm likely to do in the darkroom.