enlarger light source

[David Flockhart]

The time has come to build a horizontal enlarger for negatives up to 8X20. I have purchased an old 16X20 process camera and am looking for guidance on selecting a light source. I'll need to build the enclosure for the light and get a piece of opal glass for diffusion. Also, do any of you have suggestions about building the glass sandwich for the negative holder? I was considering something along the lines of the type in my Durst 138 but didn't know if Newton rings would be a problem. Thanks in advance for your ideas and shared experience.

[David R Munson]

In terms of illumination, you should take a look in Ansel Adams' <i>The Print</u>. On page 28 in particular there is a photograph of the two different light sources he had for his 8x10 enlarger. One is a cold light setup, the other looks like a bunch of halogen bulbs on individual switches. He goes into some detail in the text. Whatever you decide, good luck and keep us posted on your progress.

[David R Munson]

Stupid HTML...

[Sandy Sorlien]

For odd size negatives I use two clean pieces of hardware store glass which I tape around the edges. The tape (3M Photographic) separates the glass by just enough space so that there is no Newton ring problem. (Dust, though!) I cut a mask from rubylith to surround the neg so stray light doesn't come through. I use a cold light head on an old Elwood 8x10 enlarger, #15 green gel to neutralize it for contrast filters, it's slow but works pretty well.

[Stuart Whatling]

Let's see if we can lose the italics...</i></i></i>. There - how's that?

[Bruce Wehman]

Dave, Since your rig is horizontal, weight is not a problem and you can go really hog-wild with light sources. If you choose flourescent tubes, use a commercial grade ballast, so that they won't flicker when the switch goes on.....incandescent bulbs, cooling fans, go for it. You could even use an array of smaller bulbs, green and blue, on rheostats and do variable contrast.

[David Flockhart]

Thanks for the ideas. I am thinking that the flourescent idea would be the easiest and cheapest (not the only consideration but important). Of the various types of flourescent tubes are there differences that make one type a better choice? Also, what is rubylith?

David

[Sandy Sorlien]

David, Rubylith is a red acetate-backed film used in graphic design --- you can cut it easily with an Exacto knife. you could also use amberlith, which is safelight orange, or really any paper or film that would block light. Ruby or amber translucent materials let the projected image show through but would not make an exposure on b&w paper, useful if you wanted to mask out just one area of an image. I'm just using it to keep stray light away from the easel so I could use black Delta plastic just as well.