Potassium ferricyanide local bleaching

[norm123]

Hi all

Yesterday, I saw a video about a French printer who use bleaching with brush, Q-Tips between 2 baths fixing.

For me, it looks more accurate than to dodge some areas too dark.

Did you experiment this?

Any tips are welcomed.

 

[Ghostman]

Dodging and bleaching are going to do different things. How for example would you dodge the whites of someone's eyes or bleach a print back to give it a nice contrasty pop? Local bleaching is going to lift and add contrast to highlights and mid-tones. Although dodging can be used for this too, it doesn't quite do the same thing as it reduces print density as opposed to increase contrast. A toothbrush can't go where floss can but they really compliment each other

I know the video you are talking about. She prints beautifully, her hands do a mesmerizing and symbiotic dance under the light.

 

[darkosaric]

I use it for some very small places that I want to bleach - like eyes or some parts of clothes. Be careful and make very diluted potassium ferricyanide, easily you can get too light or it can spread on unwanted areas. Best is to practice on one ruined print.

 

[norm123]

Dodging and bleaching are going to do different things. How for example would you dodge the whites of someone's eyes or bleach a print back to give it a nice contrasty pop? Local bleaching is going to lift and add contrast to highlights and mid-tones. Although dodging can be used for this too, it doesn't quite do the same thing as it reduces print density as opposed to increase contrast. A toothbrush can't go where floss can but they really compliment each other

I know the video you are talking about. She prints beautifully, her hands do a mesmerizing and symbiotic dance under the light.

Yes. That's the video. The prints are beautyful.

 

[RalphLambrecht]

Hi all

Yesterday, I saw a video about a French printer who use bleaching with brush, Q-Tips between 2 baths fixing.

For me, it looks more accurate than to dodge some areas too dark.

Did you experiment this?

Any tips are welcomed.

Yes, sure; works great.brush the ferry over printareas you wish to lighten up like 'liquid light but don't forget to fix and wash afterwards.works great for eyes,clouds and other highlight needed a little extra light.I had limited success with increasing shadow detail.I think you simply need more film exposure fr that.

 

[CropDusterMan]

I often used pot. ferri. to open up the whites of the eyes in some of my close head-shots...it took some
practice to get it from looking too done...I did it during the wash phase using q-tips.

 

[norm123]

Yes. That's the video. The prints are beautyful.

I found the link.

I understand that is good to add a punch in highlight.

https://www.youtube.com/watch?v=qz2dC5MXjSY

thank you all for tips.

 

[Ghostman]

Keep in mind that bleach works on areas of lower density first (highligths, mid tones) before it starts affecting dense areas. By the time is starts working on the dense areas, the rest of your print will have disappeared

What I recommend doing is experimenting with prints that you think you've either under or over-exposed. Make a dilute solution of bleach and stick your print in there. You will see when the various areas of your print begin to become affected. Bleaching like this to varying degrees and then toning in sepia produces wonderful results. Remember that after bleaching you need to fix again.

 

[K-G]

Here you can have good use for that huge pile of scrap prints that all printers have but only a few dare to admit. The way to success is spelled PRACTICE . Different sizes of thick watercolour brushes are helpfull besides the Q-tips. Do the bleaching in many small steps and inspect in between. It is very easy to go to far. Good luck !

Karl-Gustaf

 

[M Carter]

Couple things to note:

Dilute ferri alone will bleach, but the full effect isn't seen until it hits the fix. Some people mix dilute fixer with a bit of ferri, others go back & forth between brushing ferri and splashing fix on the print.

Ferri reacts with fixer in a way that makes a ferri+fixer solution die in about 10 minutes, something to keep in mind. But for spot bleaching, you may only need an ounce or two of the solution. It's good to find a small heavy jar or something that won't tip over.

The good thing here is - 100g of ferri will last a long, long time if only used for spot bleaching.

For spot bleaching, if you have a sheet of glass or a big tray with a flat bottom, you can prop that up in a sink and keep a running hose handy. Some people like the print propped up, others like it flat so the bleach doesn't run. In either case, running water, a squeegie, and a clean cloth are helpful - if the print is wiped and blotted, the bleach won't spread as easily.

And, as others have mentioned - practice on some scrap prints! It's easy to overdo, it's easy to use too-strong a solution and then see streak-marks where you hose it off.

 

[Gerald C Koch]

Localized bleaching with ferricyanide is not as easy as it may seem. It is easy to over-bleach since the bleaching does not stop immediately upon contact with the fixer. It continues for another few seconds. So always stop before the desired effect is achieved. This takes a bit of practice.

 

[norm123]

I use it for some very small places that I want to bleach - like eyes or some parts of clothes. Be careful and make very diluted potassium ferricyanide, easily you can get too light or it can spread on unwanted areas. Best is to practice on one ruined print.

What is a good dilution to use? 100 g for 1 liter of water for stock solution and after 1+9 or more?

 

[Gerald C Koch]

What is a good dilution to use? 100 g for 1 liter of water for stock solution and after 1+9 or more?

People who use this technique regularly do not bother measuring. They add enough solid ferricyanide to produce a pale yellow solution. With practice the proper shade of yellow is easily determined. Practice on some scrap photos.

 

[darkosaric]

People who use this technique regularly do not bother measuring. They add enough solid ferricyanide to produce a pale yellow solution. With practice the proper shade of yellow is easily determined. Practice on some scrap photos.

You answered as you were reading my mind .

 

[Doremus Scudder]

Well, I guess I'm a bit more precise than many. I use a rehalogenating bleach of potassium ferricyanide and potassium bromide. I find it more controllable, longer-lived and has the advantage of the possibility of redevelopment if you go too far. Still, I figure on about a 25% loss rate.

The following is from my personal darkroom manual:

Local bleaching, rehalogenating bleach procedure
Note: this technique turns silver into “invisible” silver bromide that needs to be fixed away.
1. Prepare a dilute ferricyanide/bromide solution of about 1 to 2% by adding 10 drops of 10% ferricyanide solution and 30 drops of 3.2% potassium bromide solution (I have these on hand always) to 10ml water (or mix the appropriate dilution in larger quantity, basic solution is 1g pot. ferricyanide and 1g pot. bromide / liter). This solution is a starting point and can be strengthened or weakened as needed.
2. The print needs to be fairly free of fixer, not well-washed but well rinsed so the fix doesn't react with the ferri. 2-3 min.or so in water should do the trick.
3. Lay the print on an angled work surface, (e.g., the bottom of a flat-bottomed tray). Position the print so that the run-off does not flow over areas of low density that should not be bleached. Working with a running water hose in your left hand, apply the bleach locally with a brush or cotton swab (Chinese calligraphy brushes work well). Work from bottom to top and monitor the bleaching carefully. It is very important to keep the water running on the print directly below the area being worked on to prevent streaking by the run-off and to keep the water hose moving to keep the bleach from being directed down the edge of the water stream and causing streaks there. Before the desired tone has been reached, rinse well. It is better to build up to the desired tone slowly to prevent over-bleaching, keeping in mind that the bleaching continues for a while after rinsing. Be careful that the bleach is not working too quickly. If so, rinse the print thoroughly and repeat with a weaker bleach solution. Bleaching can cause split toning, so bleach lightly if you are planning to tone.
4. When the desired tone has almost been reached, rinse the print thoroughly with running water to remove all the bleaching agents before fixing.
5. If the bleaching process goes too far, the print can be returned to the developer, but this will result in a different size and shape of silver grain being formed from the original development, which will tone differently. If redevelopment is necessary, keep toning to a minimum.
6. The print now needs to be fixed to remove the silver bromide produced by the bleach. Give it a full-time fix in the second fixing bath.
7. Wash and dry as usual.


Hope this helps,

Doremus

 

[RalphLambrecht]

very interesting and very close to what I do

 

[norm123]

Well, I guess I'm a bit more precise than many. I use a rehalogenating bleach of potassium ferricyanide and potassium bromide. I find it more controllable, longer-lived and has the advantage of the possibility of redevelopment if you go too far. Still, I figure on about a 25% loss rate.

The following is from my personal darkroom manual:

Local bleaching, rehalogenating bleach procedure
Note: this technique turns silver into “invisible” silver bromide that needs to be fixed away.
1. Prepare a dilute ferricyanide/bromide solution of about 1 to 2% by adding 10 drops of 10% ferricyanide solution and 30 drops of 3.2% potassium bromide solution (I have these on hand always) to 10ml water (or mix the appropriate dilution in larger quantity, basic solution is 1g pot. ferricyanide and 1g pot. bromide / liter). This solution is a starting point and can be strengthened or weakened as needed.
2. The print needs to be fairly free of fixer, not well-washed but well rinsed so the fix doesn't react with the ferri. 2-3 min.or so in water should do the trick.
3. Lay the print on an angled work surface, (e.g., the bottom of a flat-bottomed tray). Position the print so that the run-off does not flow over areas of low density that should not be bleached. Working with a running water hose in your left hand, apply the bleach locally with a brush or cotton swab (Chinese calligraphy brushes work well). Work from bottom to top and monitor the bleaching carefully. It is very important to keep the water running on the print directly below the area being worked on to prevent streaking by the run-off and to keep the water hose moving to keep the bleach from being directed down the edge of the water stream and causing streaks there. Before the desired tone has been reached, rinse well. It is better to build up to the desired tone slowly to prevent over-bleaching, keeping in mind that the bleaching continues for a while after rinsing. Be careful that the bleach is not working too quickly. If so, rinse the print thoroughly and repeat with a weaker bleach solution. Bleaching can cause split toning, so bleach lightly if you are planning to tone.
4. When the desired tone has almost been reached, rinse the print thoroughly with running water to remove all the bleaching agents before fixing.
5. If the bleaching process goes too far, the print can be returned to the developer, but this will result in a different size and shape of silver grain being formed from the original development, which will tone differently. If redevelopment is necessary, keep toning to a minimum.
6. The print now needs to be fixed to remove the silver bromide produced by the bleach. Give it a full-time fix in the second fixing bath.
7. Wash and dry as usual.


Hope this helps,

Doremus

It will help a lot

Thank you

 

[Mark_S]

I took a printing workshop from Bruce Barnbaum a couple of years ago (highly recommended), and Bruce does a lot of bleaching with potassium ferricyanide. Potassium ferricyanide bleaching is good to accentuate highlights, but if you are trying to bring out detail in shadow, then dodging is still your best approach.
The way that Bruce did it was to prepare a very dilute solution of potassium ferricyanide (a few crystals in some water), and then to mount the print on a sheet of plastic, held close to vertically, with a lamp shining on the print. Then take a brush (avoid brushes with metal ferrules, the bleach eats metal), and dip it in the bleach, with the other hand, hold a hose with gently running water. Dab the areas on the print that you want to bleach with the brush, wait a few seconds and then rinse with the running water. Repeat until you get the effect that you want.

Patience is your friend here.

The bleach tended to brighten highlights on the print, but had no effect on dark, shadow area.

 

[Sirius Glass]

I use it very diluted with no bigger cotton ball than I need or a Q-tip. I have the print on a large glass plate at the sink with a cup of water to rinse as soon as the bleach has the effect that I want. I also keep a cotton ball in the cup of water so that I can apply the water to slow down or stop the bleaching.

 

[ChuckP]

I've used bleach in the shadows to open them up and increase contrast. Dodging will not increase contrast but bleaching will. Barnbaum explains it in his book.

 

[David Lyga]

My dilution for STRONG reducer is this: 1 gram of Potassium Ferricyanide for EACH 50ml of water. This is your BLEACH. It lasts indefinitely in a closed bottle. Then, for a STRONG reducer, mix one part BLEACH + one part film strength fixer. The combination will not last too long (maybe 20 minutes) so mix together right before use.

Of course, this strong reducer will probably not give you time sufficient for visual evaluation. Simply add water to the strong mixture. For example, for a far weaker solution mix one part BLEACH + one part film strength fixer + ten parts water. That will slow things down considerably and the weaker mixture will last longer before deteriorating.

Note: if you do not have a scale to weigh the potassium ferricyanide, remember that this chemical is the same mass-wise as it is for volumetric displacement. Thus, one gram of PF equals one ml of PF.

The result with somewhat age-fogged paper is rather remarkable: it cleans up the dinginess and imparts a bit of extra contrast (assuming that you started with a somewhat darker print to make up for the reduction in density). However, alas and 'darn-it', the contrast increase effect is not available with B&W film. There, the reduction is 'proportional' in that it removes the same proporation of silver from ALL densities (heavy densities give up more silver than the weaker densities because they have more to give up). With photographic PAPER, the reduction is 'cutting', meaning that the SAME AMOUNT of silver is removed for each density. The contrast increase results because, in proportion, if the same density from weaker parts is removed as from the denser parts, the effect will be to increase contrast, as one hardly notices the removal of that limited amount of silver from the denser portions. - David Lyga

 

[marcmarc]

Thanks for all the great tips. I've been interested in how this works. I'm heading to Freestyle this week so I hope I remember to pick up some up. By the way, W. Eugene Smith describes his own methods for using the bleach in the book "Darkroom" by Lustrum Press 1977.

 

[norm123]

Thank you all for your luminous tips!!

 

[skljocnulbumte]

I tried to selective bleaching with a solution of 0,5 gram of Potassium Ferricyanide + 100ml of water on fomabrom 111 paper. Results is purple/yellow color of spots/places on paper where I used solution. When I put a paper in the fixer, the purple color is disappeared, spots turn in whiter than was before fixed. The yellow color is still there. Where is a mistake? Thanks

 

[Sirius Glass]

I tried to selective bleaching with a solution of 0,5 gram of Potassium Ferricyanide + 100ml of water on fomabrom 111 paper. Results is purple/yellow color of spots/places on paper where I used solution. When I put a paper in the fixer, the purple color is disappeared, spots turn in whiter than was before fixed. The yellow color is still there. Where is a mistake? Thanks

It sounds like it works for you. Welcome to APUG