Digital BW, The Print

Steven,

Ordinary window glass is a pretty good absorber of UV.  Standard window
glaze is about 2mm, a bit more than 1/16 inch.  If your windows are 1/4 inch
thick, they are not ³standard.²  Since absorption is exponential with
thickness, a factor of 4 in thickness will be very significant.

Harry

On 10/25/07 11:29 PM, "Steven Karafyllakis" <stevekphoto@...>
wrote:

>  
> I put 4 grayscales out in my south window on 7/17. They are receiving
> 10-12 hrs of ambient light a day, with 3-4 hrs in the afternoon being
> direct (but not over-head) sunlight. The window is 1/4 inch standard
> glass.
> 
> Two scales are coated with PremierArt, two are not. Of each pair one
> is MIS K4 printed in my R1800, the other Epson K3/SP3800. Each scale
> has a black mattboard strip covering the middle 1/2-inch.  Readings
> taken with a Colorvision spectrophotometer.
> 
> MIS coated: Start, 2.4   @ 3 months, 2.35    Epson coated:  Start,
> 2.59  @ 3 months, 2.53
> 
> MIS uncoated: Start,  2.31  @ 3 months  2.25  Epson Uncoated: start,
> 2.48  @ 3 months 2.41
> 
> Lifting the strip of black cardboard, I can't yet see a divider line
> between the covered and uncovered parts on any of the scales.
> 
> The 'b' value of the base started at -3.4, initially went a bit bluer
> (OBAs burning off?) now is drifting back towards yellow a bit, but
> none of the blueness shifts are visible. This continues to be a
> warmer than average base color for an RC paper, but with  no rapid
> yellowing visible, unlike SOME of the RC papers I've tested.
> 
> I like this paper, it prints with good presence and tonal separation,
> and the warmer base makes it easier to mat.
> 
> Steven Karafyllakis

-- 

Harry F. Lockwood




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