Digital BW, The Print

I had 2 non-OBA papers in this fade test -- PermaJet Alpha and Premier Art
Fine Art Hot Press 205.  As one would expect, the non-OBA papers are much
more stable in the paper color.  Although EEM did very well in terms of
fading, the yellowing of the paper may also have significantly affected even
the 50% patch.  The 50% patches on the non-OBA papers did not yellow the way
the 50% patch on EEM did.

Readings are L*a*b* (L, a, b); L* higher is lighter, theoretical black = 0,
white = 100; a* positive is red (close to magenta), negative is green; b*
positive is yellow, negative is blue.  So, the more the L* changes in a
positive direction, the lighter it is becoming, or the more the amount of
the fade.  The more the b* (the last number in the group) changes in a
positive direction, the more the test patch has yellowed.  


Paper white:  

In general the non-OBA papers "bleached" slightly, becoming a bit brighter
and less warm.  EEM, in comparison, darkened very slightly and warmed
considerably, losing its "blueness."


Permajet Alpha 

      0% Control: 96.96, -0.11, 3.89

         600 Hr.: 97.41, -0.09, 2.40

         Change:   0.45, -.02, -1.49

Premier Art 205

      0% Control: 97.59, -0.30, 2.98

         600 Hr.: 97.90, -0.32, 2.54

         Change:   0.31, -.02, -.44



For comparison:

EEM 0% Control: 96.83, 1.03, -3.49

       600 Hr.: 96.79, -.37, 0.99

       Change:  -0.04, -1.4, 4.48


50% test patches:

The following comparisons look at the initial, pre-test readings, and then
the readings of the test strips after 600 hours.

Alpha, 4800, ABW-N, 50%:

     Pre-test: 53.73, 0.45, 3.00

     600 Hr:   54.77, 0.40, 2.76

     Change:    1.04, -.05, -.24

Alpha, UT7, modified neutral curve, 50%:

     Pre-test: 53.14, 1.64, 2.61

     600 Hr:   53.67, 1.56, 2.55

     Change:    0.53, -0.08, -.06

Premier Art 205, 4800, ABW-N, 50%:

     Pre-test:  54.53, 0.21, 1.84

     600 Hr.:   55.48, 0.08, 1.95

     Change:     0.95, -.13, 0.11

Premier Art 205, UT7, modified neutral curve, 50%:

     Pre-test:  59.64, 1.31, 0.49

     600 Hr.:   60.06, 1.19, 0.61

     Change:     0.42, -.12, 0.12

For comparison, the change in the pre-test to 600 hour readings for EEM 50%,
using the same methods as above, were as follows:

     4800: 0.90, -.70, 2.30  

     UT7:  0.34, -.75, 1.98



Paul
www.PaulRoark.com