Re: DIY light source for 10X10" enlarger.

"jjs" <nobody@[EMAIL PROTECTED]
> wrote in message 
news:R7SdnU6pz7oHcGHanZ2dnUVZ_quhnZ2d@[EMAIL PROTECTED]
> To date I've considered enlarger light sources to be engineering well 
> beyond my feeble capability, but I have used and examined only condenser

> enlargers such as the Leitz IIa and Omega condenser enlarger, but my
task 
> now is to make a diffusion thpe for the 10x10 enlarger.
>
> I want something with No built-in filtration. No fancy color mixing for
VC 
> papers. No electronics. No side-lit mixing chambers. Just a straight 
> forward light source and a diffusing layer. I question cold light,
mercury 
> va****, tubes, whatever they are because I just don't plain understand
'em.
>
> I can blunder head-first into this project, but this group has some
smart 
> people with impressive experience, so I'll put my blunder idea forward.
>
> First, I am limited to ~110V AC power although converting to DC is an 
> option. How about a simple array of 'white' LEDs at the top, pointing
down 
> over the typical sheet of plastic translucent material found in home 
> supply places?  Or should it be fine ground glass? I am not concerned 
> about the variability of LEDs over time unless they change during the
time 
> it takes to get an 8X10 negative-to-print just right - maybe a day or
two. 
> The power for the light will be run through a robust power-conditioner 
> once set aside for a big minicomputer. Batteries not included.
>
> So far so good? Corrections would be most welcome. OR just let me
blunder 
> and if it goes badly I'll post pictures of the catastrophe.
>
>

Years agom I had a Solar brand 5x7 enlarger. The lamp head was a huge
globe, 
possibly 16" in diameter, with a large base incandescent bulb. The globe
was 
silver inside. There was a pair of diffusion glasses, separated by about
one 
inch. The top glass had an additional diffusion spot in the center to
offset 
the hotspot caused by the bulb.

Why not a mixing chamber type system? Seems to me a reflective dome with
two 
or three lights pointing in would be fairly simple. Plus, heat could be 
easier to handle because the bulbs would be 'sort of' outside the dome.

My second choice would be flourescent. I don't know what's available, but 
surely someone makes a compact fixture about 12" long. Put several of them

side by side in a reflective chamber and diffuse the output. You would
have 
to use a shutter, and the color temp _might_ cause a problem with 
multi-contrast papers.

And finally, here's an outside the box possiblity: Construct the enlarger
so 
that the head is stationary and the baseboard moves. Open the head to the 
outside world, and use the biggest diffuser available, the sky!