Quote Originally Posted by L Gebhardt
How would you do this? The dicroic filters would need to be variable across the entire filter. In a color head they just move more and less of the filter into the light before it gets mixed in thr mixing box. The Ilford heads use two separate bulbs and adjust the intensity of each to vary intensity of each before the mixing box. It would be fairly easy to create a small mixing box to put above the condensers to act as a more point source.
The way that I would do this would be to begin with what Durst Pro has done with their conversion using the 1200 watt halogen lamp. In fact, even though it is expensive at $865.00. I might buy their conversion kit. Next I would buy a set of the physically largest dichroic filters that Durst or even Omega use in their color enlargers in the Magenta and Yellow spectrum. I would design an individual adjustment for each of these colors from the 0 to 200 units that they provide. I would try not to use a mixing chamber of an appreciable size since to do so would eliminate the benefits of a point light source. I think that in using a point light source no mixing chamber would be required since the lamp arc is such small dimension that the light path through the filter and any possible inaccuracy of the filter value would be on no consequence.

Why would one consider this type of a conversion? For myself, I think that the point light source would have definite benefits over a diffusion source enlarger. I have found that, even though I have three diffusion enlargers along with three condensor enlargers, that the condensor enlargers do provide enhanced local contrast over the diffusion enlargers. I have found, in my experience that the local contrast lost in the use of a diffusion light source enlarger is unrecoverable at some latter point through any printing manipulations.