Indian Head Test Pattern Question

[Terry]

Thanks Terry, I see what mean about the linotype style grey scale. There does appear to be quite few variants of this test pattern. I came across another bearing the RCA copyright mark and graded peaking verticals that has another actual grey scale indian but with less detail.

The original RCA card in post #7 is, as stated, as used in a monoscope whereas the RCA card in post #9 would have been for use as a slide or an actual card in front of a camera, so no need to resort to the linotype style dots and lines to produce the grey scale