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Dichromated Gelatin
== Dichromated Gelatin ==
=== My First 4" X 5" DCG Hologram ===
http://holoforum.org/forum/viewtopic.php?f=7&t=764
{|
| Stephen: Mold-coated with 240 bloom skin gelatin brought from eBay. Dissolved 7.5 g
of gelatin in 50 ml deionized water heated to 40-45° C, then filtered the gelatin using
filter paper and small funnel.
 
I used 60 μm shims and 6 mm thick 15" x 4" float glass for the mold. Mold was treated
with Rain-X and then heated with hair dryer prior to pouring gelatin. I soaked
2 mm x 15" x 4" float glass in a 5% hydrochloric acid solution (concrete path cleaner)
for 24 hours. The glass was then scrubbed under running water, and then rinsed with
deionized water. Finally, I treated the 2 mm float glass with silane, TOTALSEAL 7016
(used for epoxying glass).
 
After pouring the gelatin and clamping the mold, I waited until the mold had cooled to
the ambient temperature, then placed in the mold into the refrigerator for five hours.
[Note: 30 minutes would have been sufficient for the gelatin to set.] Then the mold
was removed from the refrigerator and the parted the plates.
 
The gelatin-coated plate was allowed to air-dry at ambient temperature for 24 hours. The
plate was then cut into three 5" sections. The plates were then dip coated in a 3%
solution of Ammonium Dichromate (15 g AmDi dissolved in 500 ml deionized water and 5 ml
Ilford Ilfotol). The plates air dried at ambient room temperature for 5 hours.
 
The platers were exposed at 532 nm with a ref power density at the center of the plate
measured as 432 mJ. My measured power takes into consideration the loss due to Brewster's
angle, but no measurement of object beam power.
 
I gave five minutes for dark reaction, then proceeded with the following development
steps. All baths at ambient.
* Kodak Rapid Fixer (diluted as per paper processing) until clear + 15 seconds.
* Rinse in water.
* Water tuning bath for three minutes.
* Dehydration in 50%, 70%, and 91% IPA, three minutes in each bath.
* Dehydration in 100% until diffraction was visible + 15 seconds.
 
The plates were then reprocessed with the following steps. The first bath at 32° C
and the others at ambient room temperature.
* Water tuning bath for three minutes.
* 70% and 91% IPA each for 15 seconds.
* 100% IPA until diffraction visible + 15 seconds.
 
The plates were then dried with a hot hair drier followed by 20 minutes on a
hotplate at 100° C. The plates were then sealed with cover glass.
 
Notes to self:
* Don't get the mold too hot.
* Double check which is the emulsion side before placing the plate in processing tray.
* Don't dry dipped coated plate vertically.
 
[[File:Test fixture.jpg|400px]]
[[File:HOLO 1.jpg|400px]]
|}
=== Mermaid ===
{|
| Colin Kaminski: This is a 4x5" dichromated geletin reflection H2 hologram that Dinesh, Joy and I made at their lab in San Diego. Here is a link to their work: http://www.tripletake.com. I helped a little but really the sucess success of this image was the result of their skills which they were very generous about teaching me.
[[File:Kaminski_mermaid.jpg|400px]]

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