Re: Viewer light colour temp

[T3D john bercovitz <bercov@xxxxxxxxxxx>]

>> It seems to me like you could achieve good color temperature 
>> by painting with the barium sulfate John V recommends and then
>> gluing a Wratten gel, something in the 82 series, over each 
>> opening in the viewer behind the slide.

> This, of course, is pretty much the system used in the special 
> model D Viewmaster viewer that came with the Chinese Art set. 

I didn't know that!  Fascinating.

Later, Geo. says it's a joke because it's really to correct the 
supplied orange lamp.  That brings us to an area I'm not too 
familiar with and that's the mirad? system of color correction 
where you have additive filters to add color temperature.  Makes 
no sense to me.  Well, George, what is the color temp of your  
lamps?  In the filter data, I see the 80A is supposed to correct 
photo floods for Kodak Daylight film.  I wonder what color temp 
the flood is thereby boosted to.  Barely acceptable for film?  
Gets it within range of the filters in your enlarger's color head?  
Also, there's the #79 Wratten which is supposed to convert 2360K 
to 5500K for color sensitometry.  Of course it doesn't transmit 
very much.  (You can look it up in your CRC handbook.  It's about 
11%.  Of course I also don't know how a decrease in light of a 
decade affects viewing.)

John


------------------------------

End of TECH3D Digest 17
***********************