Archived posting to the Leica Users Group, 2012/07/10
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]De : "Mark Rabiner " <mark at rabinergroup.com> A : "Leica Users Group" <lug at leica-users.org> Copie ? : Sujet : Re: [Leica] Daguerreotype Plate Sizes at 72 dpi Daguerreotype Plate Sizes were based on the avaible size of plate glass used in windows. Well the full size would have been I don't know about the cutting down into the quarter and sixteenth plate sizes the logic which was used. You often see the list on the internet listed as inches. I've not yet seen them metric. I think inches was a UK thing from way back was it not also a French thing? France went metric at the Revolution, circa 1789 the values of inches, feet, etc varied from one part of the country to another - it was decided to use a common system, 1790 - then the metric system was adopted in 1795. At the time the Daguerotype was patented by the French Academy of Sciences I doubt that the window panes had standardized sizes, rather, the guys cut the glass to fit into the gap the joiners had made, by hand ... http://en.wikipedia.org/wiki/Daguerreotype Ok from this source here Whole Plate: 6.5 x 8.5 inches (16.5 x 21.5 cm) Half Plate: 4.25 x 5.5 inches (11 x 14 cm) Really surprising maths WP = 354,75 cm2 HP = 154cm2 can't be half the remainder is lost in translation :-) I'm no scientist, I have doubts all the same here. Now about the pixels, I'm sure that the English language version of PS allows for cms - after all don't Canada and Australia use them on a regular basis? KISS principle ;-) Amiti?s Philippe Quarter Plate: 3.25 x 4.25 inches (8 x 11 cm) Sixth Plate: 2.75 x 3.25 inches (7 x 8 cm) Ninth Plate: 2 x 2.5 inches (5 x 6 cm) Sixteenth Plate: 1.375 x 1.625 inches (3.5 x 4 cm) It appears from this list the inche sizes were based on the original CM sizes not the other way around. Perhaps I should redo it with a straight to pixel from CM conversion. Though I don't know what the math is on that. Here is the source http://cwfp.biz/platesizes.php - - from my iRabs. Mark Rabiner http://gallery.leica-users.org/v/lugalrabs/ > From: Philippe Amard > Reply-To: Leica Users Group > Date: Tue, 10 Jul 2012 22:52:22 +0200 (CEST) > To: Leica Users Group > Subject: Re: [Leica] Daguerreotype Plate Sizes at 72 dpi > > Are you sure the unit used then was the inch? I'm sure the photos will be > better if you use cms ;-) Nice idea about the format, unsure about the > pixel count though. AMiti?s Philippe Tous vos emails en 1 clic avec > l'application SFR Mail sur iPhone et Android - En savoir > plus. ======================================== Message du : 10/07/2012 > 22:04 De : "Mark Rabiner " A : "Leica Users Group" > Copie ? : Sujet : [Leica] Daguerreotype Plate Sizes at > 72 dpi Whole plate 6-1/2" x 8-1/2" 468 x 612 pixels Half plate > 4-1/4" x 5-1/2" 306 x 396 Quarter plate 3-1/4" x 4-1/4" 234 x > 306 Sixth plate 2-3/4" x 3-1/4" 198 x 234 Ninth plate 2" x > 2-1/2" 144 x 180 Sixteenth plate 1-3/8" x 1-5/8" 99 x 117 I > worked the math on these plates sizes into pixels. I plan on working up some > images at these sizes which perhaps will have some resonance in our photo > DNA. Sometimes I plan on just entering the inch sizes at whatever resolution > I'm using on the print. As they are a bit small for the screen even. I really > don't know. Maybe I'll find myself using these all the time. Or hardly ever. > But It was fun doing it. - - from my iRabs. Mark > Rabiner http://gallery.leica-users.org/v/lugalrabs/ _______________________ > ________________________ Leica Users Group. See > http://leica-users.org/mailman/listinfo/lug for more > information _______________________________________________ Leica Users > Group. See http://leica-users.org/mailman/listinfo/lug for more information _______________________________________________ Leica Users Group. See http://leica-users.org/mailman/listinfo/lug for more information