[Largeformat] Converting a camera to an enlarger

[Thomas Huettemann <huette@Mathematik.Uni-Bielefeld.DE>]

From: Thomas Huettemann <huette@Mathematik.Uni-Bielefeld.DE>

Hi everyone,

we had this thread before ... I'm trying to use my camera as a
(horizontal) enlarger. For illumination of the negative I built
a wooden box with a lamp at the one end and a piece of frosted,
opaque glass at the other end. I tried different kinds of light
bulbs. One is a 150 W enlarger light bulb, which results in a
somewhat low output of light. Another one is a standard 75 W halogen
light bulb with built-in refelctor (the flood light type, not a
spot !). This gives nice bright illumination of the negative.
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.

I'd really appreciate any hints and comments !

Let me add a few comments: I know that some enlargers (e.g., Beseler)
have built-in heat filters. Maybe one could get one of those ?!
Or maybe adding another piece of (clear) glass might reduce the heat.
As for a uniform light distribution, I added an opaque piece of plastics
which yields an even light all over the negative, but the intensity
is reduced too much. I might try a second (additional) piece of frosted
glass mounted right in front of the light bulb.
I'd really like to avoid the use of condensors, because I suspect that
the lenses might be expensive and difficult to get.

	Thomas Huettemann