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Mixing a small amount of bleach without a gram scale

2F/2F

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Hello,

I just need about 15-30 mL of ferricyanide bleach for selective application with a brush. Just enough for bleaching back some bold lettering on five copies of the same print. I don't have a gram scale, but I have the ferricyanide. Any suggestions?

Please do not let this turn into a battle over spoons vs. weight vs. whatever. I just need a quick little batch of bleach that will simply work, and I don't have a scale.

I thank you in advance for your help!
 
If you have some old test prints laying around, just take some water, add a little ferri makin glight to darker shade of urine and teat on the junk prints until you have the change you want..EC
 
eclarke said:
If you have some old test prints laying around, just take some water, add a little ferri makin glight to darker shade of urine and teat on the junk prints until you have the change you want..EC
Click to expand...

That was my planned course of action, but I have some time (a few hours, or maybe a day) before I need to do it, so I thought I'd ask.
 
I would just spoon in a small amount and dissolve in water. Test it on an old print to see if it works too fast, too slow, or just right. Adjust your timing or concentration as you desire.
 
2F/2F said:
That was my planned course of action, but I have some time (a few hours, or maybe a day) before I need to do it, so I thought I'd ask.
Click to expand...

If the bleach is more dilute, you can just apply more, strong bleach will get you in trouble. I was shown bleaching with the urine color comparison (not being flip) and have mixed it that way ever since and I have a really good scales...EC
 
It should be a pale yellow color. I have scales too, and I don't use them for bleach. The bleach doesn't last very long, so mix right before use.

Black lettering on a light but not completely white background can be tricky. Lighter areas bleach faster than dark areas. It may be easier to lighten the lettering on the neg with pencil, if the neg is big enough to work on.
 
I think he might mean sodium thiosulfate pentahydrate, the crystalline version of the chemical.
 
I always keep a bottle of ferricyanide stock and use 2ml stock to 15ml water and bleach on a freshly fixed and slightly rinsed print without adding any fix. When you reach the desired tone, quickly rinse with water then into a fixer bath. It may take longer this way but it is easy to control and avoids ruining a print with too aggressive bleaching. Ferricyanide stock is made using 1tsp granules to 1 liter water. It keeps for years and can be used as the basis for many different bleaches and reducers.
Denise Libby
 
You don't need to be without a gram scale. Very suitable scales are available for around $10 on fleaBay. Just search for 'gold scales'.
Peter
 

I bleach on a piece of acrylic sheet propped up in my sink and have a hose with running water in my left hand to control bleach which flows away from the area I bleach. I keep a stream of water going against the print right under the bleach area..be careful of streaks...Evan Clarke
 
Dear Evan;
Great minds think alike, that's the exact procedure I use on prints smaller than 16X20. It's amazing what a good teacher experience is.
Denise Libby
 
The formula I posted above:
1 teaspoon potassium ferricyanide
1 tablespoon fixer
1 quart water

Fixer is 1 tblsp of working-strength rapid fix, i.e. Kodak rapid fix, not stock or concentrated rapid fix. I'm not a chemist, but I believe the reason for the fix is to slightly acidify the solution. The dilution of the fixer is too great to really have a fixing effect.
Print should be thoroughly rinsed, re-fixed and rewashed. The recommendation above for constantly running water is a must to avoid streaking and bleaching of unwanted areas.

Peter Gomena
 
Dear Peter;
Your formula is correct for a bleach solution. A plain ferricyanide solution used on a freshly fixed and lightly rinsed print will interact with the retained fixer in the print and the bleaching process will proceed much slower and be much easier to control.
Denise Libby
 
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