Re: [Largeformat] Converting a camera to an enlarger

["Pete Caluori" <pcaluori@hotmail.com>]

From: "Pete Caluori" <pcaluori@hotmail.com>

>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 Iíve 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


Greetings,

I like the different ideas and suggestions that have been presented here!

With regards to fans: my thought was exactly what was suggested, isolate the 
lamps thereby removing vibration, but as I've said, I've never done this.

I don't know how much light is required to enlarge an 8x10 negative, but 
after reading these posts I suspect it is considerable (yes, I have seen a 
pix of AA enlarger.)  I would think that quartz halogen lamp(s) might be 
more effective than incadescent.

Regards,  Pete