Archived posting to the Leica Users Group, 2012/07/10

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Subject: [Leica] Daguerreotype Plate Sizes at 72 dpi
From: john at mcmaster.co.nz (John McMaster)
Date: Tue, 10 Jul 2012 21:30:24 +0000
References: <CC2212BF.20EB2%mark@rabinergroup.com>, <CC2215B7.20EBA%mark@rabinergroup.com>

Isn't half plate 4.25" x 6.5" (rather than 5.5")?

Ah, 6.5" for glass plates and sheet film but 5.5" for tintypes - 
http://en.wikipedia.org/wiki/Tintype

Learnt something already today :-)

john
________________________________________


Here are the Daguerreotype Plate sizes worked into pixels from the I think
original Cm sizes
Whole Plate:    6.5 x 8.5 inches    (16.5 x 21.5 cm)  462 x 602 pixels
Half Plate:    4.25 x 5.5 inches   (11 x 14 cm) 308 x 392
Quarter Plate:    3.25 x 4.25 inches    (8 x 11 cm) 224 x 308
Sixth Plate:    2.75 x 3.25 inches    (7 x 8 cm) 196 x 224
Ninth Plate:    2 x 2.5 inches    (5 x 6 cm) 140 x 168
Sixteenth Plate:    1.375 x 1.625 inches    (3.5 x 4 cm)   98 x 112

Its the cm size times 28

Introducing the numbers 28 and 72 to them certainly does not turn them into
any warm and fuzzy numbers.

Here was the conversions from inches.

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

Its like translating the bible from Greek instead of Hebrew. Or whatever it
was originally written in.



- - from my iRabs.
Mark Rabiner
http://gallery.leica-users.org/v/lugalrabs/


> From: Mark William Rabiner <mark at rabinergroup.com>
> Date: Tue, 10 Jul 2012 17:11:27 -0400
> To: Leica Users Group <lug at leica-users.org>
> Conversation: [Leica] Daguerreotype Plate Sizes at 72 dpi
> Subject: Re: [Leica] Daguerreotype Plate Sizes at 72 dpi
>
> Not 32 but 28
> Conversion table
> DPI
> (dot/in)    dpcm (dot/cm)    Pitch (?m/dot)
> 72             28                              350
>
> " There are some ongoing efforts to abandon DPI in favour of metrication,
> giving the inter-dot spacing in dots per centimetre (dpcm) or micrometres
> (?m).[5][6] A resolution of 72 DPI for example equals a resolution of 
> about 28
> dpcm or an inter-dot spacing of about 350 ?m."
>
>
> - - from my iRabs.
> Mark Rabiner
> http://gallery.leica-users.org/v/lugalrabs/
>
>
>> From: Philippe Amard <philippe.amard at sfr.fr>
>> Reply-To: Leica Users Group <lug at leica-users.org>
>> Date: Tue, 10 Jul 2012 22:52:22 +0200 (CEST)
>> To: Leica Users Group <lug at leica-users.org>
>> 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 " <mark at rabinergroup.com>
A : "Leica Users Group"
>> <lug at leica-users.org>
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.



Replies: Reply from mark at rabinergroup.com (Mark Rabiner) ([Leica] Daguerreotype Plate Sizes at 72 dpi)
In reply to: Message from mark at rabinergroup.com (Mark Rabiner) ([Leica] Daguerreotype Plate Sizes at 72 dpi)
Message from mark at rabinergroup.com (Mark Rabiner) ([Leica] Daguerreotype Plate Sizes at 72 dpi)