Re: [Largeformat] Converting a camera to an enlarger

[Clive Warren <cocam@cableinet.co.uk>]

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
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