Originally Posted by Hologram
Yes, Thank you for reminding me.
You may recall I had a computer virus and had to reinstall everything; some necessary software still needs to be reinstalled...
But perhaps you are right.
You probably know there is/was a book due out (late last year perhaps?) that was to have some images as well as perhaps Lippmann's biography... Nevertheless, if you think it might be worthwhile, I will reinstall the software and finish it up. (I really need to anyway from an archival point of view. Hardware and software changes and other problems like that.)
What format do you think would be the best way to store and present the material?
Ray Rogers, what book do you speak of? I'd be very curious to know.
Sorry, I can't locate anything more specific just now.
I belive it was due out about a year ago... the author's name was "Allen" something but I am not certain it has actually been released... If I come across anything more definate, I will let you know.
1st try making a Lippmann - partial success
So I gave it go yesterday making a Lippmann Plate.
It looks like I have a ways to go to get better color rendition, but I am stoked I was able to record a standing wave pattern in the emulsion. I used GEO-03 holographic plates. Hardened the emulsion with a Glyoxal soak and developed in Lumiere Pyrogallol-Ammonia developer.
I definitely altered the emulsion too much in processing, which is why the white table is blue & the red roses in the middle of the table are not red. But the green plants at the top left & bottom right are almost green & the blue turtle on the table is very blue.
If anyone has any suggestions on how I might reduce altering the emulsion in processing, I'm all ears.
Hardener (6min): 5ml Glyoxal, 1gr KBr, 2.5gr So. Carbonate to make 500ml
Developer (2min): Sol A - 1gr Pyrogallol, 100ml Alcohol. Sol B - 10gr KBr, 100ml H2O. Mix 20ml A + 30ml B + 140ml H2O + 10ml Sat. Ammonia
Rinse 10min & soak 2min in LFN ( 4drop in 500ml approx )
All at 60deg F, except the developer seemed to be having a reaction and warmed itself to 68deg.
Did you wash after the hardening step? That is an important step to consider. Glyoxal should be removed before development. Also, Sodium Sulfate may be a good addition to the hardening solution.
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Yes, I did do a quick rinse maybe 15 - 20s. Although I did not pay much attention to this step. It only rinsed for the time it took me to reset my very finicky timer. Maybe I should have gone longer?
Originally Posted by Photo Engineer
I could not find any info on the pre-hardening the emulsion with Glyoxal. All the formulas used formalin, so I just swapped out equal amounts of glyoxal for formalin in the formulas I found.
Do you think not completely rinsing would have increased the solvent action of the developer?
I would use 2 minutes at minimum for the post hardener wash. Also, without Sodium Sulfate, the hardening would take place, but not optimally due to swell.
The Bromide at that concentration will inhibit the solvent action if not washed out. Excess Glyoxal will react with the Ammonia and reduce solvent action. So, you see that a good wash and a proper prehardener are both needed.
Oh that's good info, thanks PE
Originally Posted by Photo Engineer
I don't have any Sodium Sulfate in my darkroom pantry, so I'll need to order it.
The initial feedback I'm getting on the holography forum is that the color shift is probably due to the emulsion being thinner after processing. So the more I can harden it and avoid swelling or shrinking the better.
If I wanted to reduce the solvent action of the developer, would it be better to reduce the ammonia or increase the bromide?
Solvent action is more a function of the Ammonia with bromide being secondary to solvent action and primary to antifogging.
Decreasing amonia would probably be best.
Great results, congratulations!
Originally Posted by R Shaffer
I don't know whether the two hardeners, formaldehyde and glyoxal, act at similar speed regarding emulsion hardening.
Maybe glyoxal takes much longer.
What about baking the plate right after the photographic exposure and prior to liquid processing? I remember having done baking (without adding any specific hardening agent) with a couple of gelatin based materials, like dichromated and ferric gelatin. They required a relatively long time of treatment - say, 45 - 60 minutes at 120°C. So this definitely complicates the whole process.
Regarding your developer I wasn't aware (anymore) it had such a high KBr concentration. As PE pointed out KBr also acts as a silver solvent. By the way there are colloidal developers that contain but KBr as the silver solvent. Moreover, in my reply to your post at the holography forum I forgot to mention that ammonia is both a silver solvent and a very strong alkali. So increasing/decreasing its amount makes it very tricky in respect to solvent/developing action.
So switching to another developer may be a better option I guess. There's an alternative to the GP-2 type of developers. I was involved with people from the Russian holography forum to set up a developer which replaces the ammonium thiocyante by sodium thiosulfate. I can't seem to find that link anymore. The whole thing was done with two stock solutions, one containing the thiosulfate only (I believe).