first viable(ish) DCG hologram

Present your work.
tommyNaN
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first viable(ish) DCG hologram

Post by tommyNaN »

Image

The camera is unfortuantely far kinder to it than reality. This is also not my "first" DCG, its probably around number 20. But its the first one which didn't look completely horrible. This is based pretty much entirely on reading old holography forum posts...

So the specifics:
Knox gelatin, 12g per 100ml of water, coated by holding the plate horizontal, pouring a puddle in the middle, and then tilting it around to the corners, then running the extra off one corner. Then drying horizontally.
Senstized dip-and-dunk style with a 1% solution of potassium dichromate.
Exposed about 13 milliJ/cm^2 with 457nm light, Denisyuk.
"fixed" in 0.6 percent potassium alum, 1 percent potassium metabisulfate.
swelling bath 26C for 5 minutes.
Dried in 70%, 91%, 99% IPA for 2 minutes each, at 30C.

My current primary issue is the dreaded milkiness. The most interesting observation I have right now is that when a hologram is very milky, the pseudoscopic image is frequently pretty good. So the milkiness is between the viable fringes and the plate...
holomaker
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Re: first viable(ish) DCG hologram

Post by holomaker »

Good work ! How old is the film after the “dunk”...
tommyNaN
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Re: first viable(ish) DCG hologram

Post by tommyNaN »

It was a couple of hours old, maybe 14. I dunked it the evening before, dried it overnight, and shot it the next day.
BobH
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Location: Mesa, AZ

Re: first viable(ish) DCG hologram

Post by BobH »

Good start! Keep notes as you address each issue in turn while keeping everything else as constant as possible, including the time between coating and exposure. Visit someone who has lots of DCG holograms, good and bad, to look at, to get a feeling for how much haze is normal. You might find you're doing better than you think.
tommyNaN
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Joined: Thu Apr 30, 2020 9:46 pm
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Re: first viable(ish) DCG hologram

Post by tommyNaN »

Thanks for the encouragement... Notes and consistancy are everything... my notes are at http://www.bobdbob.com/~tjohnson/DCG/ The various issues tend to conflate each other.

I have a comercial DCG hologram (one of those round pendants) which I'm comparing my brightness to.

Right now, my results on Ultimate U8 are significantly better. I sure hope I have lots of room for improvement. (-:
holomaker
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Joined: Wed Jan 07, 2015 8:01 am

Re: first viable(ish) DCG hologram

Post by holomaker »

My current primary issue is the dreaded milkiness. The most interesting observation I have right now is that when a hologram is very milky, the pseudoscopic image is frequently pretty good. So the milkiness is between the viable fringes and the plate”

Sounds like you may want to try and put the emulsion opposite of the way u are currently shooting ...emulsion towards laser?
Ammu@2730

Re: first viable(ish) DCG hologram

Post by Ammu@2730 »

even i have coted my dcg but every after coating its not enough stick in the plate always peel-off easily. what is the wrong with my techniques?
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