Omega LPL 670 XL - Light fall off

[PNW_Aaron]

Hi,
I have an Omega/LPL 670 XL enlarger. when I convert to print medium format 6x6 I seem to have considerable light fall-off towards the edges. I followed the directions carefully removing one of the condensers and positioning the bulb correctly. I have also tried both 80mm and 75mm lenses. The issue still persist. I can even see the variation of the light distribution when there is no negative in the enlarger. To overcome this I end up burning extra on the sides however it would be nice to fix this issue if possible. Thank you for any suggestions.

 

[Doremus Scudder]

Unless the amount of edge-burning you are doing is extreme, this is rather normal. I find that most prints need 10% or so of edge-burning. If you are burning much more than this, however, there is definitely an issue with the illumination. Make sure you are stopping down at least two stops from wide-open for starters. If the problem persists, then others more familiar with your enlarger than I will certainly have advice.

Best,

Doremus

 

[Richard Jepsen]

For history the issue of light falloff is the condenser.

For MF negs you must remove a condenser and reverse (lens holder) which the lens screws into. The concave dished lens holder concave surface is on top and lens screws in the bottom. The position places the lens the farthest from the condenser.

Instructions on the condenser position are on the inner door of the enlarger face. The part sides up to remove.