The rest here is from Phil Davis.
Sandy King (Sanking@hubcap.clemson.edu)
>I just ran a couple of tests with my light bank and Ivory Black gum samples. I
>coated a sheet of paper with a fairly strong black mixture, dried it, cut two
>similar strips from the center, and exposed one piece through a step tablet to
>9 UV tubes in the center of my light bank for 10 minutes. To avoid any
>"continuing action" I began the "development" immediately. Then I exchanged the
>UV tubes for "daylight" tubes and repeated the test with the other half of the
>coated sample.
>
>Both sets of tubes are well-used but the UV tubes look OK and light up evenly.
>The daylight tubes are partially blackened on the ends and the center one in
>the array failed to light up but I let it go and went on with the test.
>
>Here are the numbers: you can plot them on 1/2-stop intervals (0.15) to see
>what the curves look like.
>
>Step # Day UV
>
> 1 0.75 0.44
> 2 0.68 0.42
> 3 0.64 0.39
> 4 0.59 0.37
> 5 0.49 0.34
> 6 0.38 0.30
> 7 0.23 0.20
> 8 0.05 0.09
> 9 0.02 0.01
> (B+F) 0.0 0.0
>
>
>Here are some palladium numbers for you:
>>During this test all nine of the tubes were active so the comparison is
>completely valid. These are, of course, the old "regular" Westinghouse Black
>Light UV 18" 15-watt white (not filtered) tubes, versus ordinary 18" 15-watt
>"Daylight" fluorescents.
>
Crane's Strathmore
>Step# Day UV Day UV
>
> 1 1.17 1.13 0.85 0.63
> 2 1.05 1.0 0.68 0.53
> 3 0.9 0.86 0.57 0.42
> 4 0.71 0.71 0.43 0.34
> 5 0.54 0.56 0.25 0.24
> 6 0.35 0.43 0.14 0.16
> 7 0.21 0.30 0.05 0.09
> 8 0.10 0.20 0.01 0.04
> 9 0.02 0.09 0.00 0.02
>10 0.01 0.04 0.00
>11 0.00 0.01
>12 0.00
>
>
>Obviously none of these test samples reached maximum black (tupically around
>1.5 for me) but I suppose that density would be similar with both lights if the
>exposures were extended sufficiently.
>
>The effect of the daylight tubes seems to be similar to the addition of added
>restrainer in the sensitizer mix--reduced highlight density and higher
>contrast. Unlike added restrainer, though, the daylight tubes produce higher
>high-density numbers. In other words, above about 0.7 density, the daylight
>tubes are actually "faster" and appear to lose out at the lower densities
>because of their higher contrast.
>
>As far as relative speeds are concerned, you can interpret the curves in
>several ways (because of the considerable difference in contrast or curve
>gradient), depending on your reference density level. If you assume that the
>toe (highlight) densities are a good speed reference then the UV tubes are
>faster; if you refer to the ANSI density level of 0.6 for silver papers, the
>two light sources are approximately equal; but if you calculate on shadow speed
>densities, the daylight tubes come out ahead. Pick the reference density level
>you like best.
>
>Again, I have to point out that these tests were done with old 18" 15watt tubes
>that have been in use for probably 20 years, intermittently. The daylight
>tubes, in particular, are definitely blackened on the ends but I don't have any
>new tubes to compare them with so I don't know how much their output has
>diminished. The UV tubes *look* better (no visible blackening) but I don't know
>how they may have deteriorated, either.
>Phil