Ah - I see. I didn't know this. And I thought holograms were such delicate things I looked up Jeff Blyth's DCG recipe, and saw that I had missed this important post processing step. He says "Finished [DCG] holograms should be thoroughly air-dried for several hours at around 60C. Once treated like this, they seem to be able to withstand ambient relative humidity below 85% indefinitely ...". I guess the gelatin becomes permanently stiffer and less able to absorb water after baking. I expect microwaving would also be effective in removing residual water, but kind of doubt that it would have have the same beneficial effect as prolonged baking...
PCGGI DCG Hologram
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danny bruza
PCGGI DCG Hologram
the output also will depend on the amps the power(12vdc 10amps) source has...it loves 10 amps or more....but needs water cooling if you run it with 10 amps
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Dinesh
PCGGI DCG Hologram
Once treated like this, they seem to be able to withstand ambient relative humidity below
85% indefinitely ...".
I'd dispute the figure. I've had holograms disappear at around 50% RH. It's not a case of baking it into a stiff, water repelling state.
The idea behind the hair dryer is to dry it quickly and uniformly without burning the gelatin. There is still resudual water in the hologram, depending on how you process it. As I said in an earlier post, DCG is a fine balancing act between a large number of factors. Like any other type of hologram, it's relatively easy to get an image in DCG. it's a lot harder to get an image that fully exploits all the characteristics of DCG. More than any other medium, I think you really need to understand both the holography and the material fairly well to exploit it to its best.
Baking a DCG hologram after processing blue shifts it, by evaporating the residual water in the hologram, as well as hardens it. This does give it a little protection, but also makes it much more receptive to capturing water. We managed to tune a hologram to below it's recording wavelength by baking, but it didn't last very long, it red shifted fairly quickly. Sealing it only delayed the process.
85% indefinitely ...".
I'd dispute the figure. I've had holograms disappear at around 50% RH. It's not a case of baking it into a stiff, water repelling state.
The idea behind the hair dryer is to dry it quickly and uniformly without burning the gelatin. There is still resudual water in the hologram, depending on how you process it. As I said in an earlier post, DCG is a fine balancing act between a large number of factors. Like any other type of hologram, it's relatively easy to get an image in DCG. it's a lot harder to get an image that fully exploits all the characteristics of DCG. More than any other medium, I think you really need to understand both the holography and the material fairly well to exploit it to its best.
Baking a DCG hologram after processing blue shifts it, by evaporating the residual water in the hologram, as well as hardens it. This does give it a little protection, but also makes it much more receptive to capturing water. We managed to tune a hologram to below it's recording wavelength by baking, but it didn't last very long, it red shifted fairly quickly. Sealing it only delayed the process.
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Tom B.
PCGGI DCG Hologram
Interesting. I wonder what the X factor is that would explain the vast difference in baking results? Type of gelatin? I suppose the blue shift you describe is from the collapse of the DCG fringe souffle, rather than its gentle dehydration with fringe structure intact. But why then would rapid high-temperature drying work better for you? Maybe it's a race between dehydration and collapse - dry fast enough and there's not enough time for much collapse to take place. Yet another DCG mystery...
RDR (http://www.xmission.com/~ralcon/stability.html ) describes using a post-processing bakeout of up to 120C (without mentioning bake times) but seems less sanguine about the amount of humidity protection gained by this for unsealed holograms.
RDR (http://www.xmission.com/~ralcon/stability.html ) describes using a post-processing bakeout of up to 120C (without mentioning bake times) but seems less sanguine about the amount of humidity protection gained by this for unsealed holograms.