- Cincinnati waterfront captured on daguerreotype plates c.1848. Restored by conservators at George Eastman House in Rochester, New York. What was unexpected is the resolution of these daguerreotypes. The panoramic set could be blown up to 170 by 20 feet without losing clarity—a digital camera would require 140,000 megapixels per frame to match it. Since the exposure time was on the order of minutes, anything that moved significantly was not imaged. Particularly interesting is seeking out the "ghosts" of slower moving people and horse-drawn buggies moving along the line of sight of the camera.
- Photographic survey of the Russian Empire c.1910. Taken by Sergei Mikhailovich Prokudin-Gorskii under the auspices of Tsar Nicholas II before the outbreak of WW1 and the Russian Revolution. This is not (Ted) Turnerization of black and white photographs but a "digichromatographic" restoration of the original color plates. I highly recommend comparing with the more recent photographic views available in the accompanying Google Map links.
Happy World Standards Day 2024
5 weeks ago
The wikipedia page on Daguerreotype photography explains that this image, made by Daguerre himself, had an exposure time that was more than 10 minutes, and it is laterally reversed (like a mirror image) "as were all Daguerreotypes," which is confirmed by the reversed characters in the sign on a building in the upper left.
ReplyDeleteThis raises 2 questions about the Cincinnati Waterfront images:
1. Why are these image not laterally reversed? See signage on river boats.
2. Why are the clock hands resolvable to 55 minutes past 1 o'clock, given such long exposure times? See item 3 in the sidedbar.
1. Daguerreotypes were often viewed in cases with mirrors that would provide a reversed view of the reversed image. It is logical to assume that the digital conservationists took the liberty of flipping the images.
ReplyDelete2. According to this exposure table (http://www.instructables.com/files/orig/FS8/MOHA/7TVEQZJISRP/FS8MOHA7TVEQZJISRP.pdf) and using the "Sunny 16 rule" (http://www.fredparker.com/ultexp1.htm) we can estimate the exposure time. It looks a little hazy, but the highlights on the boats are bright. Let's call it "weak, hazy sun" for an Exposure Value(EV) of 14. That would yield an exposure of 1.6 minutes at the generous aperture of f/5.6*. Since this was a wide angle shot, and a 6"x8" film plane, we can guess the real aperture might have been about f/11. I suppose we could calculate it but I am just making an educated guess. That is two "stops" slower so an exposure of 6.4 minutes at the most and possibly less. So the clock hand at 55 past would not be too unresolvable even with a 3-4 minute exposure. (Maybe it *was* sunnier). Also, the amount of blur on some of the standing men is what I would expect with a 1-2 minute exposure rather than a 10 minute exposure. There are some faint gray "ghosts" which are more of a mystery since if they were constantly moving would have not shown. Perhaps they were moving, then they stopped for 30 seconds or more, then continued.
More importantly, how do we know it wasn't taken at 11:10am?
The Russian photographs are beautiful.
The ISO film speed would be about 0.0008 for this.
I already thought about the time. Not only does it look (to me) like the big hand is near the 11, but there is a statement to the effect that the afternoon hour was previously estimated, quite independently, from shadow positions, relation to the known direction of the river, etc.
ReplyDeleteSeems the wiki page might be a bit off (I may have to go and have a nervous breakdown). Indeed, it seems that in later D-types, mirrors were used and the exposure times were reduced considerably.
ReplyDeletewww.photohistory-sussex.co.uk says:
John Frederick Goddard (1795-1866), a chemist, [found] a way of reducing exposure times to less than a few minutes, thereby making it possible to take daguerreotype portraits.
[ In this illustration, the operator is using Wolcott's Mirror Camera, which was fitted with a curved mirror instead of a lens ]
inventors.about.com says:
Exposure times for the earliest daguerreotypes ranged from three to fifteen minutes, making the process nearly impractical for portraiture. Modifications to the sensitization process coupled with the improvement of photographic lenses soon reduced the exposure time to less than a minute.
A laterally reversed image would be obtained unless the camera was fitted with a mirror or prism to correct this effect.
On a typographic note - THE UBIQUITY OF CAPITAL LETTERS IN SIGNAGE - is quite striking.
ReplyDeletere: SIGNAGE. Interesting point, but I'm going to guess that has a simple explanation. Even the sign on the blg in the Boulevard du Temple, Paris image, taken in 1838 by Daguerre, has all caps; as far as I can make out.
ReplyDeleteIt seems to me that are at least 3 reasons for the caps:
1. They're all a form of advertising or identification
2. They're easier to cut into a stencil
3. They're easier to read from a distance
Any lower case lettering has to be relatively smaller, by definition, and thus less legible from a distance---which is not good for advertising.