Bleach and redevolopment: active halides still there?

[Rich Ullsmith]

Hello everybody. I've been playing around with bleach and redevelopment for a while now, mostly with lith. I don't usually have bleaching and developing in mind when I print . . .mostly use it for prints that have dried down further than planned, or too flat. Basically, playing around for my own amusement.

Typically after the redevelopment, two bath fix and a healthy wash (permawash too, if the print has promise for toning.) I've become accustomed to the disappointment of watching the redeveloped print bleach back in the fixer, even if it was taken to full redevelopment. I understand that the whole process generally results in some loss of density and highlights.

Getting lazy the other night, I decided to save some time: instead of wash/fix/fix/wash after development, why not just toss it in some sepia toner? I figured if there was any silver halide left in there, it would be converted.

Well, poof! There is all the highlights, they came right back (albeit in sepia, but so what!).

So my question is: why would the silver halide be developed in the sepia, when it wouldn't in the developer? I even left a few in the developer several minutes after infectious development ran its course, and still the sepia brought it back. And if there's any chem folks out there, is it possible I could get the highlights back from the developer by adding some NaOH (basically, lith part B)?

Interested to hear facts and opinions on this.

 

[dancqu]

At least for myself your post is confusing.
You do say that the print DOES redevelop in
the developer then bleaches in the fixer.
After bleach into the sepia toner? Dan

 

[snallan]

If you are redeveloping the bleached prints in lith developer, are you leaving them to develop for as long as you did for the original print?

Infectious development in the mid- and shadow-tones may appear to be complete, but if you are developing for a shorter time than the original, it is probable that little development has taken place in the highlights (thus the redevelopment in the sepia toner).

 

[Rich Ullsmith]

No, I let it develop for several minutes past the infectious stage. I understand that the process involves some loss of density and highlight. The question is why do the highlights pop back up in the sepia toner when they would not come back in the developer? Obviously there is still unconverted silver halides present when redevelopment has come to a halt.

 

[snallan]

Yes there will still be undeveloped halide left after the redevelopment in lith developer. Perhaps try the redevelopment in a normal print developer, or try redeveloping with lith developer under fairly bright light, and allow ten or fifteen minutes beyond the apparent end of infectious development.

Lith developers act strongest in regions where there is a lot of silver being reduced by developer (thus the infectious effect - as more silver becomes reduced, the faster the reaction goes for adjacent exposed, but yet undeveloped silver halide). Where there is little silver, as in the bleached highlights, the development is going to remain pretty sluggish in dilute lith developer.