laser pens and photography

[P3D Martin Simon <msimon@xxxxxxxxxxxxxxxx>]

>My question: how well do typical color slide and negative films respond at
>these wavelengths? The He-Ne laser worked pretty well with color negative
>film. From a photographic standpoint, is paying a few tens of dollars more
>for a 635 nm laser pen (compared to the cost of a 670 nm model) justified
>by increased sensitivity of the film at that wavelength? 
>John R

     I have made similar photos to what you describe using both a HeNe
laser and a 670 nm laser pen.  The film sensitivity was fine in both
cases.  I recently got a 4 mW 650 nm laser pen from MWK and it is much
"brighter" to the eye than the 5 mW 670 nm pointer.  Haven't tried it
with film.  It isn't a very pretty pointer but it is only a few 10's of 
dollars more (about $58) than the duller 670 nm.  I am sure that 635 nm 
pointers are brighter still, but they cost about $100 more.  Of course,
for painting a scene onto film, you can compensate for less brightness
by scanning slower, or using a more reflective material.


Martin Simon   msimon@xxxxxxxxxxxxxxxx    www.physics.ucla.edu/~msimon


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