From: Robert W. Schramm (schrammrus@hotmail.com)
Date: 04/23/02-09:23:31 AM Z
William,
Perhaps you could build a machine to do this but I expect it would be very
expensive because of the precision required. Let me use the analogy of
polishing a telescope mirror. This is done by hand because the figure of the
mirror must be accurate to 1/8 a wavelength of light which is pretty small,
i.e. on the order of 10 to the -13 cm. Polishing is done by repeated testing
and variations in pressure between the tool and mirror. Polishing a
daguerreotype plate is done in a similar way except that the final polish
does not have to be as precise as a telescope mirror. The plate is
frequently examined under a strong light and adjustments are made in the way
pressure is applied to different parts of the plate in order to acheive an
even polish. You may not know this but a plate to be used horizontally
(landscape mode) is note polished in the same way as one to be used
vertically (portrait mode). There are also small variations in the amount of
rouge on the buff, the nap of the buff itself and the surface of the plate,
all of which would have to be taken into consideration by a machine.
Possibly, you could scan the plate as it is being polished and feed the data
to a computer controling the polishing machine. You would need to write an
appropriate program of course.
Bob Schramm
>From: William Linne <photoassistant@hotmail.com>
>Reply-To: alt-photo-process-l@sask.usask.ca
>To: alt-photo-process-l@sask.usask.ca
>Subject: Fw: To preserve a daguerreotype. Questions
>Date: Mon, 22 Apr 2002 18:28:11 -0700
>
>
>----- Original Message -----
>From: "William Linne" <rebus66@hotmail.com>
>To: <alt-photo-process-l@sask.usask.ca>
>Sent: Monday, April 22, 2002 6:24 PM
>Subject: Re: To preserve a daguerreotype. Questions
>
>
> > Sorry to be so dense, but why is the final polishing better when done by
> > hand? It just seems silly to me to say that a human hand is better at
>this
> > sort of mechanical task than a machine. I am not trying to be
>inflammatory,
> > I really would just like to know. What is the science behind it?
> >
> > thanks,
> >
> > William
> > ----- Original Message -----
> > From: "Robert W. Schramm" <schrammrus@hotmail.com>
> > To: <alt-photo-process-l@sask.usask.ca>
> > Sent: Monday, April 22, 2002 4:34 PM
> > Subject: Re: To preserve a daguerreotype. Questions
> >
> >
> > Richard,
> >
> > Yes, I am aware of that but also I know of a local amateur astronomer
>who
> > made a mirror grinding machine which he used down to the last
>carborundum
> > grit and then finished by hand.
> >
> > Bob Schramm
> >
> >
> > >From: "Richard M. Koolish" <koolish@bbn.com>
> > >Reply-To: alt-photo-process-l@sask.usask.ca
> > >To: alt-photo-process-l@sask.usask.ca
> > >Subject: Re: To preserve a daguerreotype. Questions
> > >Date: Mon, 22 Apr 2002 09:37:34 -0400 (EDT)
> > >
> > > > I do my initial polish with a wheel. Even though it is a special
> > >jeweler's
> > > > wheel with special bearings and other things to reduce vibration to
> > >almost
> > > > nothing, I still must do the final buffing by hand with two buffs. I
> > >cannot
> > > > explain in words how to polish a dag plate. One must be shown by an
> > > > experienced daguerreotypist. A poorly polished plate not only gives
>a
> > >poor
> > > > image but is not as sensitive as a properly polished one. I have
>read
> > > > somewhere that the early daguerreotypists had machine powered
>leather
> > >buffs.
> > > > Perhaps something could be devised but I do not know how well they
>would
> > > > work. During my training I was taught how and where to place my
>hands
> > >during
> > > > buffing and how to get an even polish. Also how to know when the
>plate
> > >is
> > > > correctly polished. It struck me as being similar to mirror grinding
>for
> > > > astronomical telescope mirror when the final stage is also done by
>hand.
> > > >
> > > > Bob Schramm
> > >
> > >
> > > Optics (telescope mirrors, lenses, etc) are traditionally polished
> > >with a
> > > pitch lap and rouge. Amateurs often make small mirrors completely
>by
> > >hand,
> > > including the rough grinding.
> >
> >
> >
> >
> > Check out my web page at:
> >
> > http://www.SchrammStudio.com
> >
> > also look at:
> >
> > http://www.wlsc.wvnet.edu/www/pubrel/photo.html
> >
> >
> > _________________________________________________________________
> > Join the world's largest e-mail service with MSN Hotmail.
> > http://www.hotmail.com
> >
> >
> >
> >
Check out my web page at:
also look at:
http://www.wlsc.wvnet.edu/www/pubrel/photo.html
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