stuck with DCG, always dim or foggy

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Sergio

stuck with DCG, always dim or foggy

Post by Sergio »

Joe Farina wrote:Tony, thanks for posting that. After giving it some more thought, I'm not sure how important the layer absorption (or beam ratio) is for DCG. I seem to recall Dinesh saying that large ratios of reference to object could still result in very bright DCG holograms. I know this is not true for reflection silver halide holograms, the beam ratio has a big effect, and should be close to 1:1 for optimum brightness. Also, consider Cristiano Perucci's very bright MBCDG holograms. With MBDCG the absorption is much worse, Kubota in one of his papers said it's around 90%. Yet Cristiano's single-beam reflection holograms look very bright indeed.

As for the amount of dichromate in regular "blue" DCG holography, it does of course influence speed (and I would assume lifetime of stored plates), and the amount of shrinkage (when that bulk material washes out of the emulsion during processing).

I personally put more emphasis on the shrinkage factor (when using blue light), and that's one reason why I like to use the minimum amount of dichromate.
So if the recording fringes are strong enough to impair in this region the bubble formation, even at low transfer modulation the result will be strong void formation onto exposed region, resulting in a kind of filtering this condition to "OK" bit="1" Denisyuk hologram, the result on this low ratio level maybe noise?
Dutchelm05

stuck with DCG, always dim or foggy

Post by Dutchelm05 »

The testing base line is to test the ammount of light absorbed by the Amdi ? so i would think the way to do this, point your test probe at laser beam @ film-plane take reading (this is the the whole), and now introduce the film in it's film holder,then take reading seeing thru unprocessed film (this is the part),now the part/whole this is the ammount of light left. The only constant need to be the wavelenght..........?[/quote]

Hope you had a good vacation Dave. This was exactly how I did it. I am not sure why Rollison suggested 50/50 since as you guys said there are other factors.
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