Holographyforum.org / holowiki.org

I just got this. I think it provides a good heuristic approach to holography, albeit not as analytic as the coupled wave approach.

Machine vision recognition of holograms is apparently difficult due to speckle and noise. This paper applies deep learning techniques for holographic recognition by machine vision.

https://www.nasa.gov/feature/innovative ... ts-healthy

"This was the first holoportation handshake from Earth in space."

The curve in the post above is not exactly the true picture, as it is a graph of relative sensitivity, not absolute, unlike this curve, from Agfa Technical Information Bulletin 21.7271(688)LI, the rest of the bulletin available here: http://edweslystudio.com/Materials/AgX/Agfa/Holotest217271688.PDF...

Hi Jody Have you tried exposing the old red sensitive plates to green laser light? Obviously they don't have the correct dyes to be sensitive to green but given modern green lasers are fairly powerful I wonder if the emulsion would respond anyway? John, I think that the red emulsion would respond t...

Hi Jody, a few years ago I had exactly the opposite problem: red Agfas (more than 20 years old) worked perfectly, while the green ones were completely dead. Petr Petr's observation makes me think it could be caused by random events. If so, this could be due to double random walk ("drunkard's w...

thanks Din, so if the dye because age or heat becomes bleached, why not just dye it again there by restoring the dyes ability to transfer energy to the silver? mm nice info :P I suppose you could. This was brought up recently. I think you'd have to choose your dye carefully; it must take in the las...

The surprise finding (to me) is that these very old materials have lost two to three orders of magnitude of sensitivity as they’ve aged. Although not included in this series of test exposures, similar legacy green sensitive materials from the same manufacturers have not lost much sensitivity. Since...

My feeling, based on a long ago run series of tests on the effect of various hardeners on freshly mixed Knox gelatin, was that isopropyl, unlike ethanol & methanol, had the possibility of leading to a crazing or milkiness of gelatin. For what it's worth, I've definitely noticed this with respec...