Ultraviolet spectrally responsive holograms in dichromated gelatin

Swell 3% gelatin (Russelot, 200 bloom) in distilled water for 12 h at 20 °C.

Dissolved gelatin with mild agitation; increase temperature 1 °C/min to 60 °C, then decrease temperature at same rate to 50 °C.

Add 2% chrome alum by weight of dried gelatin, then decrease temperature at previous rate to 45 °C.

Pipet out and spread solution over 20 cm × 20 cm leveled glass plates (30 cm³ each).

Dry slowly (30 h) at 18 °C, then store at ~ 18 °C and relative humidity ~ 45%.

Soak plates in 2% ammonium dichromate solution for 10 min at 20 °C.

Dry in horizontal position overnight at 20 °C.

Keep plates during the selected period of time at 20 °C and relative humidity ~ 100%.

Wash plates in running water for 30 min at the selected temperature accurate within ±0.5 °C.

Dehydrate in baths of 50%, 90%, and 100% isopropanol at 20 °C for 5 min each time.

Dry in dessicator for 24 h at 20 °C and relative humidity of <10%.

Heat plates in an oven at the selected temperature.

Seal holograms with a glass cover and epoxy adhesive.

Swell 3% gelatin (Russelot, 200 bloom) in distilled water for 12 h at 20 °C.

Dissolved gelatin with mild agitation; increase temperature 1 °C/min to 60 °C, then decrease temperature at same rate to 50 °C.

Add 2% chrome alum by weight of dried gelatin, then decrease temperature at previous rate to 45 °C.

Pipet out and spread solution over 20 cm × 20 cm leveled glass plates (30 cm³ each).

Dry slowly (30 h) at 18 °C, then store at ~ 18 °C and relative humidity ~ 45%.

Soak plates in 2% ammonium dichromate solution for 10 min at 20 °C.

Dry in horizontal position overnight at 20 °C.

Keep plates during the selected period of time at 20 °C and relative humidity ~ 100%.

Wash plates in running water for 30 min at the selected temperature accurate within ±0.5 °C.

Dehydrate in baths of 50%, 90%, and 100% isopropanol at 20 °C for 5 min each time.

Dry in dessicator for 24 h at 20 °C and relative humidity of <10%.

Heat plates in an oven at the selected temperature.

Seal holograms with a glass cover and epoxy adhesive.