It seemed like a simple question . . . (Converting an 8x10" camera to an enlarger)

[Stephen Samuels]

. . . but Google just can't answer it.

I'm adapting my 10x8 monorail for use as an enlarger, which seems to be quite a common practice when seeking to save thousands and your floor joists by not buying a real one. But as i wade through everyone's thoughts and experiences on light sources, i find i'm unable to decide because i don't know an appropriate light output from the head would be to allow modest enlargements (not murals) and printing times.

Can anyone help? What is my lumen ballpark? Anyone who can give me a range in which to work, will get my thanks!

Appreciate your help.

Stephen

 

[frank]

It'd be more important that you achieve even illumination, and to protect the neg from too much heat. A weaker light source will work, simply with more exposure time. Try a 60 or 100 watt household bulb in an aluminum foil lined cardboard box with frosted glass or translucent plexiglass to diffuse the light source.

 

[Stephen Samuels]

Thanks Frank. I was erring towards LEDs for simplicity and low temperature but am in interested in your single bulb suggestion. Would a single bulb produce enough light to print 10x8 in less than a fortnight? Especially after it's been through enough diffusion to give even coverage?

i'm realising how little i know about all of this.

 

[frank]

I think that with a foil lined box, and having the diffusing panel close to the neg, to increase efficiency, it should work with an exposure time measured in units shorter than days.

 

[ac12]

Look for a WHITE 100w G40 bulb.
The G40 bulb at least gives you a larger illumination source to start from.
I would think that if you are not going to print very large, say 11x14 it should work fine.
I think the light output becomes more of an issue when you print LARGE.

gud luk

 

[ic-racer]

seeking to save thousands and your floor joists by not buying a real one.

The size is related to the physics and optics. Making an 8x10 enlarger out of a camera does not change that.

 

[Dr Croubie]

How about one of those LED panels used for studio lighting? (like one of these).

Get an 8x10 one with a few hundred white LEDs on it and stick a diffuser in front of it. (would a GG work as a good enough diffuser?)

 

[JohnC]

LED panel as an enlarger light source ?.... interesting, but. I suspect having say 50 LEDs pointing at the neg, will be similar to 50 point light sources confusing the image as it passed through the lens. Certainly, a diffuser will be needed. You could achieve some interesting effect by using a sheet of acrylic embossed with diamond-shaped texture, as often used under fluoro tubes. Or you could try bouncing a LED plate into the top of the box/lamphouse without a diffuser. Have fun.

 

[Stephen Samuels]

Thanks for all the responses, i'm gradually getting a sense of how this all works.

A de Vere 10x8 generally has 1200W of tungsten in it (it looks as though Ansel Adams had quite a bit more in his - 36 bulbs!) which throws off 18000lm. The LED panel i was thinking of was a ceiling tile type - 300mm square with an array of LEDs behind opal acrylic - but this only produces about 1500lm which may be ok for small enlargements but is it worth the risk?

I went on to look at halogen floods - 5 inch-ish long tubes - a couple of which would do 1000W but has anyone ever enlarged using halogen? Is the quality of light right?

I'll continue to dig but any further thoughts will be gratefully received.

 

[frank]

If you have a studio strobe, mono light or box with heads, you can use this, with suitable diffusion. Multiple pops to provide enough light if needed.

 

[ic-racer]

has anyone ever enlarged using halogen? Is the quality of light right?

Most enlargers either came with halogen lamps or had an optional head that used halogen lamps. The quality of light is excellent. The major drawbacks are heat, power consumption and the need for a well-designed mixing box. Most halogen heads on the marked have been designed accordingly and were expensive.

Keep looking around. 8x10 heads are frequently up for sale. Some time the rest of the enlarger is free when you buy the head

 

[SebastianKrauss]

I've a LPL 4x5 Enlarger with a 250W Halogen spotlight. This is almost too much for my taste. I'm very sure, that you don't need 1000w for 8x10 if you aren't printing murals all the time. My theory is that Power was a marketing gem for the enlarger manufacturers as resolution is today for digital cameras. 100 Watt might be a bit dim however. I plan to use four 50w GU 5,3 12V spots for a similar project.

 

[ic-racer]

I'm very sure, that you don't need 1000w for 8x10 if you aren't printing murals all the time.

I'm very sure that you need at least 1000W if using contrast filters, process lenses at f22 or greater, add in a center filter and expired film etc. Your base times can easily climb over 1 minute. Now do a 3x burn on the sky...