Whoa. Cold light heads require a condensor? Not mine. Mine is definitely
diffusion type in the sense that there is a diffusion plate between the tubes
and the negative stage.
Earl
*********** REPLY SEPARATOR ***********
On 11/14/2003 at 7:04 AM Bill Pearce wrote:
>There are really three types of heads, condensor, cold light, and
>diffusion.
>(well, there is point source, but that's for microfilm) Diffusion is a
>relatively new thing.
>
>I recently replace the variable condensor head on my D2 with an Ilford 500
>VC diffusion head. Diffusion light sources are the common type in color
>heads. If you've ever had a color negative hand printed by a pro lab, it's
>99ure it was on a diffusion head. People have translated color
>filtration
>to VC filter settings, but success is limited, as you can't get a full
>range
>with the normal color printing filters. Then, Ilford (and others?) made a
>head that is of the same design, but for VC paper. Two bulbs project light
>through dichroic filters into a mixing box, with a piece of opal plexiglass
>on the bottom. This is the head I have been using for about three weeks.
>
>I find that the contrast is indeed less than with the condensor head.
>Scratches are reduced, although not eliminated, and dust is hardly affected
>at all. The great advantages are the ease of changing filtration
>(especially
>for split filtration), and the fact that the negatives are not heated, and
>don't pop as readily.
>
>Cold light heads are a different animal. They use flourescent tubes, and
>require the same VC filters as a condensor head. If buying one used, be
>careful. Special tubes are required for VC paper. Uneven or inconsistent
>light can be a problem without a compensating timer.
>
>Bill Pearce
>
>
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