Over vs under lens contrast filters

[Ben johns]

Is speed of use the only advantage of below the lens contrast filters? ilfords below the lens filters are about double the price but as the filter tray is 3x3 on my enlarger I would have cut the smallest above lens filters they offer to size which could be a huge pain.

 

[drsilver]

You'll have to excuse me, but going into the wayback machine for these thoughts. Haven't used an enlarger for 30 years, but I assume the technology is the same.

Beseler enlargers have a tray, not only above the lens, but above the negative and the condenser. I don't believe I ever used it or gave using it any thought. Now that you bring it up, that might be better as you're coloring the light source before it hits the image. But, like I said, I always used PC filters below the lens unless I was using an enlarger with a dichroic color head. With that head I could dial in the PC filtration at the source.

So, I guess, all things being equal, above the lens is probably marginally better, but below the lens works just fine. Sounds like you've got other considerations like hardware on hand, modifications to make it fit your system, etc. I'd say go with the path that makes most sense with your configuration.

 

[StephenM]

Above the lens colours the light. Full stop.

Below the lens colours the light, but the filter is another optical component that at best won't degrade the image, but will add to light scatter.

 

[Ben johns]

Cheers for the replies. For the sake of ease it doesn’t make sense to do something that could potentially take away from the photo, plus above the lens is cheaper. Just have to make a jig to cut around.
cheers again