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26% Ferric Oxalate vs. 20% Ferric Oxalate

donbga

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Hi Everyone,

Yesterday I attempted to mix a fresh batch of a 26% solution of Ferric Oxalate. No matter what I tried I could never get all of the dry FO into solution. This was Bostick & Sullivan FO. I also used an addition of oxalic acid and EDTA - tetra.

I can make a 20% solution relatively easily.

So if I use a 20% solution how will it affected palladium printing? If I've calibrated digital negatives with 26% FO will I see a major difference in prints. I assume that there will be a reduction in emulsion speed.

Thanks,

Don Bryant
 
Hey Don,

How hot are you mixing? Mine goes into solution fairly quickly if I start with the water at 180 F. Used to be 120 was sufficient. Reheating will not help.

- Keith
 
jkschreiber said:
Hey Don,

How hot are you mixing? Mine goes into solution fairly quickly if I start with the water at 180 F. Used to be 120 was sufficient. Reheating will not help.

- Keith
Click to expand...

Hi Keith,

I'm starting out with boiling water heated in the microwave, so at least 180F, so I dunno . You are right, reheating doesn't help.

Thanks,

Don
 
Don Bryant said:
Hi Keith,

I'm starting out with boiling water heated in the microwave, so at least 180F, so I dunno . You are right, reheating doesn't help.

Thanks,

Don
Click to expand...

Don-- For what it is worth, my method is to weigh out 13 grams of Bostick and Sullivan Ferric Oxalate, put it into a 50 ml bottle, and add 50 ml of water (in Seattle the tap water does just fine). Then I place it on a coffee cup warmer (small hot plate for keeping a cup of coffee warm). Occasionally I give it a vigorous shake. In about 30 to 45 minutes it gets rather warm (I can still pick up the bottle) and it all goes into solution. No problemo.
As to what would happen if you lowered the concentration to 20%, sounds like a topic ripe for experimentation.

Cheers, Ron Reeder
 

Well guys I guess I'm not holding my mouth right. The guys at Bostick & Sullivan suggested that a 20% solution should be easy to dissolve.

Thanks,

Don
 
Last edited by a moderator:
Don Bryant said:
Hi Everyone,

Yesterday I attempted to mix a fresh batch of a 26% solution of Ferric Oxalate. No matter what I tried I could never get all of the dry FO into solution.
Click to expand...

Problem resolved. The issue was caused by user error.

1) Raised water temp to boiling.
2) Used reading glasses to measure water volume correctly.

All of the FO goes into solution within about an hour, most dissolves within minutes.

Thanks everyone,

Don Bryant
 
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