Bleaching + Sunlight = Toning?
Introduction
During my prior post on Sepia toning I had a thought about bleaching somewhat unrelated but inspired by the moment.
I was inspired as I was taking photos of the prints in the bright
sun after bleaching and I was aware that the ultraviolet from the sun was
probably 'printing out' the image much as a lumen print does. (Ultraviolet light is energetic enough to leave metallic silver that makes a visible image.) Naturally as this
was a bleached image it would only print out the silver in areas where it was
left in the latent image. The non-image silver had been removed by the fixing stage.
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Original Image (note lack of density in upper and upper right of
image) |
So I took another test print with good densities and endeavored to bleach it
back as far as possible. This I did with 7 minutes of potassium ferrocyanide
1+9 solution. What remained of the image was some deep shadows and a faint
latent image. I then placed this is the sunlight for a few hours and took a few
photos.
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| Bleach Start Comparison |
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| Image from comparison time 16:00 |
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Sunlight start time 16:11 |
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Sunlight time 17:47 |
The sunlight did indeed reveal the latent image. It went quickly at first
within the first 10 minutes or so but progressed for over an hour.
The obvious question is what next for this? Since the silver is not 'stable'
when 'printed out' in UV light one could expect the print to change over time.
But I believe it will remain as an image and is unlikely to fade though it may
change color over time. I would guess the bromide ions from the rehalation
bleach are still in the paper and could over time with enough humidity and
under darkened conditions recombine with the silver ions and render the image
fainter. Washing may be sufficient to prevent this.
The alternative is to fix the image or to develop it again in conventional
developer. Fixing probably won't change much but may remove undeveloped silver
halogens as well as the bromide ions and this should keep the image from changing.
Redeveloping it should return it to a cooler gray/black tone.
Bleach Experiment:
Divide paper in 4 pieces.
- Dampen one piece but don't rinse. Keep in darkened place for a few days keeping it damp.
- Redevelop with ECO 4812. Wash and dry note change in color and density.
- Fix in rapid fixer then wash and dry. Note change in color and density.
- Keep one reference piece unaltered
Here are the results from a single scan. None of these were sepia toned only bleached.
The results are interesting. On the left was the re-developed image. This brought back most of the image in neutral grays but only in the most exposed parts of the image. It retains much of the original tonal warmth in the highlights.
Fixing the image retained most of the detail with little change. Leaving the paper damp in darkness for two days seems to have faded it somewhat which I surmised was the bromide in the paper recombining with the silver.
Finally on the right is an unmodified strip I left on a north facing window sill it ensure it didn't fade.
I ran one more experiment. Here is the same scan but the Damp Darkness strip was re-exposed in sunlight. With re-exposure the image darkened which seems to confirm my theory.
Selenium Toning
I later decided to add selenium toning to the above tests as a final trial of the different effects. I used my 1+3 concentration and toned for 5 minutes for the full effect. Looking at the result the most obvious effect is the the developer strip on the left is now brown edging towards purple throughout. Some of the yellow tones in the others appear attenuated.
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| Selenium toned |
Conclusion
I think there is a subject here of using bleaching and sunlight to tone prints. I would suggest that the original print should be printed a stop or two darker as the bleaching seems to reduce the contrast where the image is only fixed and not re-developed. My only caveat here is that the deep shadows are typically difficult to bleach away entirely in my experience. This might be mitigated with higher bleach concentration or longer bleaching times.
Re-development seems to restore the shadow image tones much more, so re-development my not warrant printing darker.
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