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Silver Halide Films and Plates

Workin' out with Irena

Tom B.: Same plates and technique as usual (BB-640, 6% TEA, lit for photo with OptiLed amber from about 1.5 m). The pics didn't come out as well this time, but good enough. The fringe pattern under the models is intentional - I calculated a mickey-mouse model of spherical wavefront interference and printed it out on cardstock as a background, but alas it moved a bit so it's dark under Irena's hand.

Olympic.jpg

Here is a stereoscopic pair photographed from the hologram. Look through the image to get the two halves to merge into a single image. Olympic stereo.jpg

More of Tom B.'s work is show-cased at http://members.shaw.ca/holopix/My_holograms.html, complete with a chronology of his ever-improving efforts.

My First...

PeterZ: This is my first reflection hologram using Integraf holokit, with PFG-01. Exposure time was 25s, distance between laser and plate 37 cm. Not very good photo. I'll do another one using polarizing filter and camera with manual focus.

PeterZ first.jpg

Litiholo Kit

Simple Transmission of Car

Transmission hologram by Arturo with Litiholo kit.

Arturo Liti car1.jpg Arturo Liti car2.jpg

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.

Test fixture.jpg HOLO 1.jpg

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 success of this image was the result of their skills which they were very generous about teaching me.

Kaminski mermaid.jpg

Musical Angel

John Pecora: On the left, 488 nm, 30 second exposure, fixer, water, alcohol. On the right, also 488 nm and 30 second exposure, then water for 25 seconds, then fixer, water, alcohol. Both exactly the same except the water prior to fixer soak.

If you look on the right near the head in the white hologram you will see a type of whiteness and it starts to blur into the angels head on the white hologram. It seems to be where the emulsion is thin. The emulsion actually seemed to crystalized. It's not that is it cloudy but it reflects the light off the emulsion like a white haze. The more more of an angle the replay light the more diffusely reflecting the haze is and the further into the hologram it moves (all the way over to about half way across the head where it is blurry).

Also what I noticed is the hologram on the left, when dried with the hot air just dried and got brighter and shifted colors. The one on the right exhibited that white crystalization (not cloudy) that then cleared up and went away to yield the hologram.

JohnFP AngelMusic.jpg

Compass 215M Test

Dave Battin plays with his Coherent 215M running at just under 30 mW. This hologram was a 6 minute exposure using one concave mirror, rapid fix. and dip sensitizing method. The dip sensitizing method involves the following:
  • Coat gelatin onto glass and allow to harden.
  • Dip hardened plates into solution of AmDi (15 g), H2O (500 ml), and soapy water (10ml).
  • Allow to air dry.
  • Expose.

Battin 215M.JPG

Two Color Test

Combined red and green beams by Joe Farina.

Farina DCG marbles.JPG

Two Color Figures

Joe Farina: These were done with Jeff's MBDCG formula, except that boric acid was used to adjust the pH, and Rhodamine 6G was used as the additional green sensitizer. The exposure was a combined 532/633 beam, with 14mW for 532 and 20mW for 633, measured after the spatial filter, the holograms are simple SBR Denisyuk. Plates are about 5 X 5 inches, and the exposures were around 20 minutes.

One of the figures was painted with a few colors (very crudely), and the other figure was painted silver. The silver-painted figure helps me to get a better grip on whether the hologram (as a whole) is more narrowband or broadband. The plate on the right has a serious flaw (but also the best color reproduction) because there is a patch across the lower faces and upper chests of the two figures. This seems to be where the emulsion overheated in the oven. (I made a mistake by laving the glass directly on the inner floor of a homemade oven, I will correct that next time.)

The colors came out fine. The outer robe is green, the inner garment is red, the scroll is white, the skin tone is tan, the hair is dark brown, with some lighter brown areas. I'm surprised the scroll came out so white. These two wavelengths (532 and 633) seem to be capable of reproducing a great many colors, but of course anything containing blue won't show up. I'm confident that this exact system will work very well if blue is added, for full color.

Farina DCG figures1.jpg

Farina DCG figures2.jpg

Farina DCG figures3.jpg

Little MBDCG Holo

Hans: Here is a sample of a MBDCG that I just made with my adjustments to the original MBDCG. Due to temperature/moisture in my garage, I would never have been able to do this in my garage with classical MBDCG as was invented by Jeff Blyth because of fading (crystallizing) of the MB in the plate.

Exposure time was 5 minutes with a TEC controlled laser diode. The plate was processed as follows:

  • First a long wash (10 minutes) in cold water to wash out the chemicals.
  • A swelling bath at 26C. I found that for thick coatings, this bath needs to be at least one minute. Otherwise, dim areas will appear on the hologram.
  • 35% IPA at 25C, two minutes
  • 70% IPA at 25C, two minutes
  • 99% IPA at 25C, three minutes

I use no fixer.

Remember that in classic DCG, the fixer is needed to convert the Cr(V) to Cr(III). It is the Cr(III) that hardens the fringes in the gelatin. With MBDCG it is the Methylene Blue that does that job. Cr(VI) is converted directly to Cr(III) upon illumination, and thus eliminating the need for a fixer.

In previous experiments I found a great benefit in using a hardener before the swelling baths. But because my hardener was getting old so fast, I started to experiment with post exposures. I found the effect to be similar. I prefer the post exposure method over a hardening bath because it cancels out two big variables: Temperature of the hardening bath and age of the hardening chemicals.

With a post exposure there is only one variable: Post exposure time. Experimentally, a post exposure time of 1/7 of the normal exposure time seems to work fine. I just wiggle the plate in the expanded laser beam at about the same distance where the plate was when the hologram was exposed.

I have not found a little difference in bandwidth between post exposed plates and chemically hardened plates. Post exposed plates indeed are a little bit more broadband. But that to me is a benefit.

Hans NewFormula1.jpg