Re: Dry Plates too!!

Hi,
I couldn't say what was "standard" when glass dry plates were in
common use, standards then seemed to be a little less "standard".
I'd have to measure a number of different brands of plates and
probably different sizes to start getting an idea of what was the
most common thickness. But...
The 1.5mm you mentioned is available from glass supply houses that i
have found on the web. I'd tell you where except my bookmarks search
keeps crashing my browser.
   And, 1mm = .040 inch. so 1.5mm =.060 inch. 1/16th inch = .
062 so all you really need is 1/16th inch glass.
    As far the flatness of hardware glass goes, the nice people
shooting wet plate images often use ordinary window glass from a
hardware or picture framing shop - no problem.
As far as I have been able to find out, no one in N. America is still
making glass plates even for scientific use, Kodak did up until just
a few years ago. They were also soooooo expensive that a regular
person could not afford them. There is a place in Eastern Europe
that still coats glass plates for photographic use, they are in
quarter plate size I believe and also very expensive even before you
ship glass overseas. I've also heard that Ilford does as well.
Robert Newcomb
On Jun 22, 2006, at 4:01 PM, Bogdan Karasek wrote:

> Hi,
>
> Since we are on the topic of "Dry Plate" as the carry base for the
> emulsion, I am thinking in terms of glass dry plate as the carrying
> medium. I have a number of 8x10 and 5x7 glass plate holders, and I
> measured the thickness of one of the glass plates that shattered in
> transit. It is 1.5mm in thickness. Was this a standard thickness
> for glass plate?
>
> Were would I be able to acquire glass plate in that thickness? I
> am assuming the local hardware store is out since window glass is
> not usually the flattest of glass that one can find nor the right
> thickness. Is there someone in N. America that still makes glass
> plates, for scientific purposes? I read somewhere that astronomers
> still use glass plates for making time exposures over several
> nights. Where do they get their plates?
>
> Any clues and information would be most welcome.
>
> Regards,
> Bogdan
>
> Ryuji Suzuki wrote:
>
>> From: Robert Newcomb <newcombr@uga.edu>
>> Subject: Re: Dry Plates too!!
>> Date: Thu, 22 Jun 2006 08:09:20 -0400
>>> I too am interested in learning to make a gelatin emulsion that
>>> can be coated onto glass for in camera use. Since very large
>>> sheet film is getting harder to get and way more expensive I am
>>> motivated to do something for myself. I have used photo paper
>>> in pinhole and lens cameras in the past and can be quite happy
>>> with the slow speed and non- panchromatic light response.
>> That's a more realistic first goal.
>>> The store bought emulsions seem to suffer from fog, vary from
>>> batch to batch due to age and are expensive.
>> Well, you'll have the same problem with your home-made emulsion.
>> In order to make the emulsion keep better, you'll have to have
>> additional chemicals (that are not available from your favorite
>> photographic suppliers) and refrigeration.
>> Another problem with paper negative is that paper emulsions have very
>> low resolution.
>> Glass plates also have interesting flaws such as halation, unless
>> antihalo coating is made. People in this group would probably rather
>> have halo for interesting effect, though.
>
> --
> ________________________________________________________________
> Bogdan Karasek
> Montréal, Québec e-mail: bkarasek@videotron.ca
> Canada
>
> "I photograph my reality"
> __________________________________________________________________
>
>
Received on 06/22/06-02:51:44 PM Z