Ok, guys

I've put on my Sherlock cap, lit the pipe and :?:

- The light comes out through the lens - not a leak somewhere else.
- The 'halo' is only visible when the red filter is in place; it's actually light coming out of the lens at such a wide angle that it overpass the red filter assembly (much larger light circle than the working area);
- It gets stronger the smaller the printing is, and disappears (or I simply can't see it) at large enlargements, with any of my 3 lens;
- At the smallest enlargement possible (head fully down), the Computar 50/2.8 is the worst, the Nikkor 40/4 is second and the Nikkor 50/2.8 is the best, halo wise.

I've tried using only one condenser lens in both possible positions, but then the light circle was too small.

Solutions:

- I will use the 40/4 only for enlargements larger than the 50/2.8 are capable of (that was the original intention, BTW).
- I will paint mate black the lens mounting ring (I had to order a custom one since the original part would not accept a lens when mounted inverted, and 'tomorrow I will paint it', you know...). :oops:

Thanks again,

Jorge O