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Discussion in 'Alternative Processes' started by Peter Schrager, Aug 29, 2017.
Nice video from Joe Van Cleeve
Hope the link works
Nope didn't go through...someone fix this
here you go peter !
( i just cut and pasted the entire URL )
Thank you John...great stuff!!
The only thing I think he goes a little overboard on precautuons...ibe used all kinds of acids
Use long sleeves and gloves plus eye protection...and pour carefully!!
thanks for finding this video peter ,
just watched it ( or most of it )
interesting the process doesn't require a clearing bath ..
usually it is develop, bleach, clear, fog redevelop ...
now i gotta find a healthfood store
Places to find the 35% HP
Hot tub and spa stores
heath food stores
Excellent! I first heard about this around a year ago here on APUG, and read this pdf, and honestly I wasn't sure if it was crackpot or not. Really cool to see Joe making actual reversal prints with it.
Darn Darn Darn... I was really hoping that at the end of the video Joe would pull out a direct positive selfie of him wearing all the protective gear. Oh well.
I like the emphasis on safety and being careful, and he needs to think about art student types who might be watching and try to convince them that it's not expensive or difficult to be careful and safe.
I've only played with Sabattier effect for reversing... not dichromates, and the permanganate recipes I've seen use sulfuric acid. So this is pretty interesting. I wonder if the drugstore 3% solution would work if you were willing to wait longer?
Isn't hydrogen peroxide volatile? That might be another good reason to mix it outdoors.
Also, would the bleach contain silver after use, or does it turn the silver into something that will be removed by the fixer? Might need to dispose of the bleach more carefully if it contains silver. IDK.
When I had my cabinet shop, I used to spray catalyzed varnish as a finish. I used 50% benzoyl peroxide as the catalyzing agent, that shit burns the daylights outta your skin when atomized, even mixed in varnish in small quantities. I used to wear a full tyvek suit and forced air respirator in my paint booth with exhaust fans on high. I don't think Joe can stress caution enough.
I'm a rank beginner when it comes to this reversal processing, so I was merely using, as a starting point, the process as described in the PDF linked on Ned's post above. In that PDF, he mentions skipping the clearing bath, which is what I did.
My initial results, using Arista RC grade 2 paper rated at ISO3 and 9% peroxide bleaching solution, was pretty dim; although I was still excited that I got a positive image at all. It wasn't until I doubled the concentration of peroxide to 18% (and doubled the exposure) that I got the results shown in the video, which is rather similar to my results with Harman DPP. As I indicated in the video, if you brightly illuminate the print, it looks very good, but under dimmer room lighting it's noticeably darker than an equivalent Harman direct positive print. I think this has to do with brighteners in the paper, which are being obscured in the reversal print by the bleached silver highlights. At least, that's my theory.
Would using a clearing bath help the highlights appear brighter? Any of you reversal experts, chime in please!
I knew I was being a bit pedantic regarding the safety equipment, but also take some responsibility for posting a video of a process that someone else might want to emulate. Better safe than sorry, and the cost of the gear isn't that high, considering the potential consequences. FWIW, I work with wet processing equipment in the semiconductor manufacturing world, involving all kinds of nasty chemicals, so this was actually a bit on the minimal side of what's needed to remain safe.
I should have mentioned segregating one's waste stream containing high concentration of hydrogen peroxide. Wipes or paper towels with lots of oxidizer can spontaneously ignite if mixed with other materials containing, for example, solvents.
I didn't go back and retest that bottle of bleaching agent, I'll try it this week and see if it's still active.
Thanks for the feedback, I look forward learning from your experience.
Wonder if the use of higher contrast developer (at either stage, negative or positive) would help with your highlights not clearing.
A bit more work with the reversal direct positive print process. Some success, but more variability than I'm used to. Still an experiment in progress.
My daughter and I are going to give the process a try as an alternative to collodion wet plate and gelatin emulsion dry plate tintypes. I watched all of Joe's videos. I really enjoyed his documentation of the process. The paper and H2O2 arrive tomorrow! Hopefully, we'll shoot on Friday.
Joe, am I correct that you ended up using a 15% H2O2 concentration for bleaching? What were your final citric acid amounts for that concentration.
I ordered some Arista EDU Ultra RC Black & White Photographic Paper, Glossy #2 5x7 that I will cut down to fit my 4x5 film holders. I am planning on using Dektol 1:3 to develop and Kodak Professional hardening fixer and perhaps a sodium sulfite clearing bath after the bleach and fixing steps.
The 35% H2O2 is tough to source around here. I checked numerous pool/spa stores, beauty supply shops, and health/vitamin/nutritian stores with no luck, so I turned to Amazon. They seem to be able to get away shipping the stuff via USPS 2nd day, so I should have a quart by tomorrow.
Do you find the Arista paper is panchromatic, meaning I have a chance at metering it correctly? I am used to working with AG+ emulsion and collodion wet plate, where the UV response makes an exposure meter all but useless.
I think the graded photopaper is mostly sensitive to blue and UV. I'd guess exposing it will be similar to AG+. And it's true that exposure meters are sometimes less than helpful, although if you compensate for the angle of the sun and cloud cover, they will get you "in the ballpark".
It sounds like a stepped test exposure is in order to calibrate the paper, maybe at ISO 1.5? if I take an incident light meter EV reading under the lighting of the test, I can usually figure out relative values for various conditions, based upon the best exposure. At least it works ok for AG+.
i think in the video he says his solution is 9%
i spoke with some chemical suppliers and they said
the shelf life is short for higher than 10% ...
Thanks! I checked Joe's blog and it appears he modified his process and chemistry some in his latest tweaks to the process. From the latest blog entry:
Expose in-camera at ISO 1.5
Develop in a 1+15 dilution of Ilford Universal Paper Developer (300mL water + 22 mL concentrate) for 1:30
Rinse in water for :30
Bleach in solution of 175mL water + 125mL 35% hydrogen peroxide + 2 teaspoons citric acid for 3:00
Rinse in water to wash off residual peroxide
Squeegee print dry
Expose under enlarger, set to 20" height at f/8 aperture, for 8 seconds
Develop again for 1:30; you can see, under the red lights, the image turn positive
Rinse or stop bath for :30
Fix in paper fixer for 2:00
The concentration of H2O2 works out to just under 15% with the quantities given. He is also being careful to keep everything under safelight conditions until after the fix. In the first video he did not control the second exposure at all and had room lights on after removal from the bleach. Joe commented this was likely causing mottled spots in the post-process highlighted bleached regions due to residual sensitive regions and over-exposure.
thanks don !
i hadn't been to joe's blog, just watched his last video
and i could have sworn he suggested it was 9%.
high concentration HOHO scares the heck out of me
im hoping there is a work around for scared-cats like me
while i am confident i would have no problem diluting
35% down .. i'd rather not deal ...
Hey Folks, I've been slow to update this thread with results from these experiments. I'm still not at the place where this process is reliably reproducible in various scenic lighting conditions. And I see dramatic differences between grade 2 vs multigrade paper.
As indicated above, I'm currently using a H2O2 dilution near 15%. And I'm processing everything under red safelights until in the fixer - and the 2nd exposure I'm trying to keep as controlled as possible.
I still see some odd markings on sky highlight areas, that seems to decrease if I reduce the bleaching time. So it seems I still need to optimize the bleaching to a bare minimum time required, for a given dilution of H2O2, without excessive bleaching, that evidently either does something to the unexposed halides or affects the underlying resin coating on the paper.
I'm not seeing a very effective pre-flash using my halogen light source I use with paper negatives, as the shadows remain blocked up; perhaps a UV preflash light source is needed. OTOH, it's easy to get confused with this process, because there are two exposures happening - the shadows get reversed after the second exposure, so perhaps the light source used for that 2nd exposure needs to have more UV, for better shadow detail.
John, I can understand your concern about working with 35% H2O2. I only handle it in that concentration when mixing a working solution, and take the precautions of face shield, chemical resistant gown and gloves. And also think about your feet, if you knock a bottle over on the table. So also keeping the container in a larger, shallow chemical tray is good insurance. Once I have a working solution, I still wear the face shield and gloves in the darkroom, as it's easy to don and doff the shield.
Thanks for confirming, Joe. I'm going to try some prints later today.
thanks joe !
i look forward to your next installment
I just completed my initial experiments with the reversal process Joe outlined in this thread. I used the following process, similar to Joe's, but modified for Dektol 1+2 developer and a different 2nd exposure light source:
I used Arista EDU Ultra RC Black & White Photographic Paper, Glossy #2 5x7 cut to 4x5 to fit the film holders.
Expose in-camera at 1 sec at f/16 in full sun with incident light reading of EV 13.33 with diffuser on meter
Develop in a 1+2 dilution of Dektol for 30 seconds to 1 minute.
Rinse in water for 30 seconds
Bleach in solution of 175mL water + 125mL 35% hydrogen peroxide + 2 level teaspoons citric acid (8.2 grams) for 3 minutes
Rinse in water to wash off residual peroxide
Expose under 60 watt equivalent Daylight balanced LED floodlight, set to 24" height for 10-30 seconds
Develop again for 30 seconds - 1 minute; you can see, under the red lights, the image turns positive
Rinse 30 seconds
Fix in Kodak Professional Hardening Fixer for 2:00
Wash for 3 minutes
The test exposures were made using a Graflex Super Graphic camera and Schneider-Kreuznak Symmar-S MC 5.6/210mm lens
Getting ready to mix 15% hydrogen peroxide bleach
2 level teaspoons of my citric acid powder has a mass of 8.2 grams
60 watt equivalent LED daylight-balanced spotlight in aluminum reflector holder. For the second exposure, this was about 24 inches from the image.
Test scene, shot off the front porch. I reversed this left to right to match camera prints.
Test exposure, processed with a long 20 second secondary exposure. Base exposure was f/32 at 1 second with an incident light reading of EV 13.33 (full daylight). I selected f/32 at 4 seconds as the best exposure and used f/16 at 1 second as the equivalent exposure for the test prints.
Typical print after first development. Note strange spot in street. This is BEFORE bleaching, so something odd going on. I suspect the Dektol was strong and the print was immersed unevenly in the developer.
First print at f/16 and 1 second. 30 sec. second exposure. The Dektol 1+2 reached maximum density in 30 seconds. I continued to over-develop for 1.5 minutes, which contributed to the graniness, colored cast and poor bleaching. The secondary exposure was too long as well.
Second print at same exposure. Even more over-developed on both exposures. Second exposure about 20 seconds. Uneven immersion in developer caused uneven bleaching and weird blotches, I think.
Third print at same exposure. Over-developed but with shorter second exposure (10 seconds). There is some weird shadowing in the bright areas of the street. Uneven immersion in developer caused uneven bleaching and weird blotches Less mottling in sky, though.
Fourth print. Shorter development seems to yield the most improvement (30 seconds on both stages). 15 second secondary exposure. Shorter development. I took more care to immerse evenly in developer. Weird shadows gone.
Last try for the day. I bumped up the exposure one stop, kept secondary exposure at 15 seconds and development times to 30 seconds. Bleaching works much better with shorter development.
Overall, I'm quite encouraged. I'm looking forward to more experiments with the process. As Joe just mentioned, getting a nice white highlight is proving to be a challenge with the added variables. I think a more dilute developer might help,
The color cast is not as evident viewed in-person as in the scan.
I wonder what the citric acid is doing for the bleach?
Don, good results. I've heard that the silver from the first development combines to form silver citrate, which is light colored and not light sensitive. The peroxide helps form citric ions to help attract the silver.
For less mottled highlights I reduced bleaching time to minimum time to fade the image; I suspect excess bleaching causes the peroxide to attack either the already bleached silver citrate, or the underlying emulsion or resin - not certain.
Others here are also experimenting with this process, hopefully they'll share their results soon.
Thanks for the comments, Joe. I know the focus of the thread is using the peroxide bleach, but as I was completely unfamiliar with reversal developing, I made up a small amount of Kodak R-9 Potassium Dichromate bleach (full safety precautions!) and tried to make a few prints as a comparison point to the peroxide. The Dichromate bleaches the print completely white after about 10 - 15 seconds when fresh, so is certainly more active than the peroxide. I used my two 2400 watt-second Speedotron 102 flash heads at 3 feet from a test subject. This gave me repeatable lighting. I use this setup at full 4800 WS for wet plate tintypes. The approximate ISO of the sensitized collodion I use is 0.5 to 1 depending upon the age of the collodion. Since I was shooting the Arista #2 RC paper at ISO 1.5, I figured I could use my wet plate exposure as a benchmark. I ended up with one 4800 WS flash pop (2-2400 WS heads at key/fill 50/50) at 3 feet between subject and lighting at f/11.
Initial efforts came out poorly, until I dialed in the exposures. The finished image was completely black. I found that I needed to perform the second exposure for MUCH longer than anticipated, about two minutes or so. A faint positive image appeared, which seemed to be a good indicator that I had fogged the paper sufficiently. The image then darkened during the second development.
I also diluted my Dektol developer to 1 + 3 in order to get enough control of density during the initial development. I used a weak Kodak indicator stop bath to stop development at the desired point.
I also had to use a Sodium Sulfite clearing solution after the dichromate bleach to clear the orange staining of the paper. This would not be needed with peroxide.
After bleaching, followed fogging for a few minutes, this is the appearance of the paper before second development:
This is the image after the second developer:
Here is a second test image using the cutoff piece of paper from the 4x5 sheet, same exposures and processing:
My next step is to try the same exposures with the peroxide bleach and compare the results.