daguerreotypes

Topics not fitting anywhere else.
Din
Posts: 401
Joined: Thu Mar 12, 2015 4:47 pm

daguerreotypes

Post by Din »

It wasn't Gabor, it was apparently Daguerre
daguerre.jpg
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Joe Farina
Posts: 803
Joined: Wed Jan 07, 2015 2:10 pm

Re: daguerreotypes

Post by Joe Farina »

I would guess that not many people have seen real Daguerreotypes. A while back, there was an exhibition of old Daguerreotypes at the Snite Museum at Notre Dame (Indiana), and I saw them for the first time. They are quite startling, compared with the type of photographic images we're used to. The resolution looked extremely high, certainly I didn't see any hint of grain, and the images had a "solidity" that is hard to describe.

Just recently I looked for Daguerreotypes on eBay. I would like to have a good example, someday. They have to be seen in person to be appreciated, maybe that's something they do have in common with holograms.

It was a somewhat morbid experience seeing those 19th-century Daguerreotypes, though, because many were of dead people at funerals. Apparently that was customary at the time. I think that long exposure times were needed, and of course there would be no problem with movement.
jrburns47
Posts: 164
Joined: Mon Sep 14, 2015 2:48 pm
Location: Oyster Bay, NY

Re: daguerreotypes

Post by jrburns47 »

I don’t know about now, but I was able to pick up a dozen small framed portraits a decade or so ago at a flea market very inexpensively. Agreed that they’re special.
Martin
Posts: 131
Joined: Sat Apr 04, 2015 2:36 am

Re: daguerreotypes

Post by Martin »

Joe Farina wrote: Fri Aug 20, 2021 6:29 pm They are quite startling, compared with the type of photographic images we're used to. The resolution looked extremely high, certainly I didn't see any hint of grain, and the images had a "solidity" that is hard to describe.

Actually, it looks like resolution is high enough to record holograms on "dags". See: https://av.tib.eu/media/20997
Din
Posts: 401
Joined: Thu Mar 12, 2015 4:47 pm

Re: daguerreotypes

Post by Din »

Martin wrote: Sat Aug 21, 2021 3:26 am
Joe Farina wrote: Fri Aug 20, 2021 6:29 pm They are quite startling, compared with the type of photographic images we're used to. The resolution looked extremely high, certainly I didn't see any hint of grain, and the images had a "solidity" that is hard to describe.

Actually, it looks like resolution is high enough to record holograms on "dags". See: https://av.tib.eu/media/20997
The paper quotes a grain size of about a micron, and a fringe width of 2.4 microns. This comes to a spatial frequency resolution of about 400 l/mm. This is high enough to record holograms at low angles. A 488nm laser would have to be recorded with an interbeam angle of about <10 degrees.

However, another 19th century imaging process known as a Carbon print has a resolution of 4000 l/mm. The Carbon print process was essentially the recording of a photograph on glass coated with potassium dichromate, an essentially 19th century dcg hologram-like process. We wondered if therefore, you can actually record a surface relief hologram on material same as that used in the 19th century. We showed this in 2004 by recording a surface relief hologram using the old 19th century Carbon printing process. We recorded with an interbeam angle of 30 degrees at 488nm, showing a resolution of about 1000 l/mm, high enough for a standard transmission hologram, though we could have gone as high as 5000 l/mm. The idea behind the paper was to show that dcg may be used as a resist material, so we then transferred the hologram onto a plastic substrate. One advantage of using the Carbon print method was that resolutions far higher than photoresist can be attained, processing with only warm water. Another advantage was that the glass Carbon print was not destroyed on transfer.

Edit: the efficiency quoted by the daguerreotype process was quoted at about 3 - 4%. Our Carbon print process was about 30%.
Martin
Posts: 131
Joined: Sat Apr 04, 2015 2:36 am

Re: daguerreotypes

Post by Martin »

Din wrote: Sat Aug 21, 2021 10:12 am We showed this in 2004 by recording a surface relief hologram using the old 19th century Carbon printing process. We recorded with an interbeam angle of 30 degrees at 488nm, showing a resolution of about 1000 l/mm, high enough for a standard transmission hologram, though we could have gone as high as 5000 l/mm.
That's quite amazing!
The idea behind the paper was to show that dcg may be used as a resist material, so we then transferred the hologram onto a plastic substrate.
For embossing?

[
One advantage of using the Carbon print method was that resolutions far higher than photoresist can be attained, processing with only warm water. Another advantage was that the glass Carbon print was not destroyed on transfer.
Interesting. So you could make high quality embossed holograms on such grounds?
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