Mixing Edwal FG-7 with Sodium Sulfite

[pompu]

Hi,

I have decided to start some compensating chemicals. So I bought a

bottle of FG-7 and also a bottle of sodium sulfite. (As I read in

many books)

 

Now the problem is that I have no clue as to how to mix the 'powder'

to the solution. Can anyone help me with this?

 

FYI, I have 300+ rolls of experience with D-76, Tmax, c41 and e6

film processing. I've just always used premixed chemicals or had

detailed mixing instructions.

 

Thanks in advance,

 

Ted

[todd peach seattle, washi]

It's been twenty years since I did this, but I just added the powder to the 'ready for use' developer in the measuring cup, then stirred it with a mixing paddle. It dissolved readily. One quirk: you get about a 2 degree F rise by the reaction, so start a couple degrees cool (68 to 70 or 70 to 72, can't remember).

[omar_fernandez]

Instructions for Edwals FG-7 is locate here:

 

http://www.fineprintsphoto.com/edwal.html

 

Mixing the sodium sulfite with water to get it into solution requires a lot of stirring. Remember to use the correct development time, as it is different than without sodium sulfite.

 

Good luck.

[dougmiles]

I have used this combination in the past and thought it worked out very well. I'd mix up several gallon jugs of 9% sodium sulfite solution to keep on hand. Then use that later instead of water as needed when preparing the developer in a 1:15 ratio.

 

How to measure the sulfite powder into the water to make 9% solution? Too many years, I've forgotten that detail! But I do recall that for consistency I made up a single several-gallon size batch in a larger container, with warm water to help the powder dissolve. A small measuring error is less important with larger quantity...

[ben_crabtree]

I agree with both Omar and Doug:

 

As Doug says, it's much easier, with less chance of a mixing error, to mix up big batches (e.g., a gallon) of the solution. The proportion is 45 grams per 15 oz. of water; I've read that this equates to one teaspoon of SS per 15 oz. of water.

 

As Omar says, make sure you use the correct time for the SS mixture. I used the plain water time by mistake a couple of days ago. Boy, those were contrasty negatives!

[pompu]

Thanks everyone for all the helpful information.

Now I can't wait to go home and try it myself!!