>> Can anyone give me a run down of what's available, what to look at &
>> what to avoid? Thanks.

> The only manufacturer I know that's still making cold light heads is
> Aristo (http://www.aristogrid.com/cold_light_chart.html).  They're sure
> to have one that will satisfy your needs.

> And a word of advice:  whichever one you get, get the light tube balanced
>  for variable contrast paper.  V54, I think.  The VC tube will work with
>  both VC and Graded types of paper.  There's even a tube balanced for
> color papers, but if you intend to do color, too, I would recommend that
>  you just get an Omega color head.  It will work just fine with b&w and
> it's a diffusion type head just like most cold light heads.