Enlarger does 6x9, but condenser unit only 6x6! Advice needed

You might try putting some sort of opal glass in place of the condensers and use it in diffusion mode. (I say this of course, without any idea how this enlarger is set up and constructed.)

 

First, make sure you have a 105 lens.

 

Yes, you need a 105mm lens. Your 80mm does not have the coverage for the 6x9cm neg. Whatever lens gives a "normal" view for the format you are using should also be the size lens used for enlarging. examples are: 50mm for 35mm format, 75mm for 6x4.5cm, 80mm for 6x6cm, 90mm for 6x7cm, 105 for 6x9cm, and 135 for 4x5 inch format.

Rick

 

Emil, try a 105 mm lens as the 80mm does not have enough coverage for 6x9. The 105mm will allow the lens to be further away from the negative stage where it can provide coverage of the 6x9 neg.

 

IIRC, some condenser enlargers have a way to move the condenser up or down to concentrate the light onto smaller or larger areas. This allows shorter exposure times for smaller formats but vignettes on larger ones. Is yours adjustable? It's probably a knob that turns a shaft to raise/lower it. Otherwise, as others stated, try a longer lens.

 

Is your machine designed to accomodate 6x9cm format? It may only handle 6x6 or 6x7cm formats. If that is the case, then you will need a different machine that will accept the larger negative. Mike1234 is correct in stating the condensers need to be adjusted apart to refocus the light. Your alternative is to remove the condensers and use a piece of opal glass for diffusion. You might like the look of diffusion , as it is slightly softer, and hides dust somewhat.

 

Yes, the diffuse white translucent type. A white acrylic will work as a diffuser, but if there is much heat build-up, it will not be happy for very long.

Even glass with a finely ground surface might work if it is far enough above the negative to avoid the textured surface falling within the depth of field of the enlarger lens focus range.

I'm not sure where one might find opal glass -- perhaps a place that supplies material for stained glass crafts might have something. I'm thinking that years back I've seen that sort of glass occasionally used in lighting fixtures, such as flush ceiling fixtures.

 

Just an idea - search for magnifax 3, they can go up to 6x9 and they are very very cheap. I got mine for 20 euros with 105 mm lens.

 

Maybe this photonet member could help you:

http://photo.net/photodb/user?user_id=732467

Matt

 

Are you sure the condenser shouldn't be LOWERED?

 

The coverage in question has to do with the illumination, too short a focal length lens will cause the corners to darken as it is seeing around the edge of the condensor in the way a wide angle lens sees more area in front of you. The 105 hopefully will correct the geometry without changing the condensor.

 

An approach I have used in the past is to make condenser lenses.

Big glass condensers are way too difficult but any lens that converges light should do, even a Fresnel lens. The "whole page magnifiers" I find at my local bargain store for $2 can be cut with scissors to fit an enlarger head. My last lamp-house conversion needed a stack of three Fresnels. The optical quality is terrible but, hey, these are condensers and a sheet of frosted glass smooths out all optical sins before the light gets to the negative. So far, so good. Nothing has melted or caught fire.