Re: [Largeformat] Converting a camera to an enlarger

[Dick Streff <ds85035@navix.net>]

From: Dick Streff <ds85035@navix.net>

Re: The 90 degree head design.

The discussion about the right angle heads brought to mind one I
recently saw on ebay:

	http://cgi.ebay.com/aw-cgi/eBayISAPI.dll?ViewItem&item=210566853

If you look at the second pic you'll see the homemade right angle head
the seller apparently made. It used twin 14" condensers instead of a
diffusion source. Might be a good design to copy if one was to go this route.

I have no affiliation with the seller, etc. Too bad I don't live closer
to Houston or I might take a stab at it myself.

Dick Streff




Clive Warren wrote:
> 
> From: Clive Warren <cocam@cableinet.co.uk>
> 
> At 5:55 am -0800 1/12/99, Pete Caluori wrote:
> >From: "Pete Caluori" <pcaluori@hotmail.com>
> >
> >>From: Thomas Huettemann <huette@Mathematik.Uni-Bielefeld.DE>
> >>Hi everyone,
> >>
> Snippety
> >>However, I have two major problems to solve:
> >>
> >>1. Heat. Especially with the reflector, the glass and the negative
> >>    get very hot with time.
> >>2. Uniformity of illumination. All types of bulbs I've tried so far
> >>    give a quite distinct fall-off towards the edges.
> >>
> >
> >Hi Tom,
> >
> >I think I have a solution to both of your problems.  While I’ve not actually
> >done this, I have been thinking about this for some time. Rather than keep
> >the light source, negative, lens and paper in a straight line, offset the
> >light source 90 degrees.  You would have to build a light/mixing chamber.
> >Something that was coated/painted bright white. I was thinking of using thin
> >sheets of Styrofoam to line the inside of the light chamber, as this would
> >help to diffuse the light even further.  I believe Omega made an enlarger
> >that worked exactly this way.  Should heat remain a problem with the lamp in
> >this configuration, a small muffin fan could be added to aid in cooling.
> >
> >When I get the time (one of these years) I plan on trying this.  I was going
> >to build the light chamber out of cardboard and/or masonite and/or wood and
> >line the inside with thin sheets of white Styrofoam.  A thin piece of opaque
> >Plexiglas would complete the light box and provide the final diffuse light.
> >Good luck and let me know what you find.
> >
> >Regards,  Pete
> 
> Well, the Omega Dichroic E head uses a 90 degree angles light and a light
> box which contains a lens and a mirror.  At the base of the box is a piece
> of opal plastic which varies in thickness across the width of the box.  The
> plastic is thinner at the edges to compensate for light fall off.
> 
> Guess that this provides the ultimate in terms of even illumination but you
> may get away with a piece of plastic or opal glass of constant thickness.
> 
> Good luck with the project.
> 
> All the best,
> 
>              Clive   http://www.cocam.co.uk
>                      Photographic Services, Filters and Equipment, Infrared FAQ
>                             http://clive.bel-epa.com
>                             Adventures in Cyberspace - Digital Art and Photos
> 
>