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From: joyce@hpcehfe.HP.COM (Joyce E. Farrell)
Newsgroups: comp.graphics
Subject: Re: Persistence of various phosphors.
Message-ID: <880001@hpcehfe.HP.COM>
Date: Mon, 2-Nov-87 16:13:28 EST
Article-I.D.: hpcehfe.880001
Posted: Mon Nov  2 16:13:28 1987
Date-Received: Sat, 7-Nov-87 00:01:16 EST
References: <1978@gryphon.CTS.COM>
Organization: Hewlett-Packard Corporate Engineering Human Factors
Lines: 18


The general rule is that if two phosphors are matched for persistence,
the phosphor that will be more likely to cause flicker will be the
brighter of the two.  If two phosphors are matched for persistence and
luminance, they will be equally likely to appear to flicker.
The red, green and blue phosphors have relatively short persistences and
are not that different in their phosphor decay rates.
I am guessing therefore, that your green phosphor was brighter than
your red and blue.  You may have sent the same DAC values (or voltage
values to the electron guns), but green would appear to be brighter 
because of the fact that people are more sensitive to wavelengths 
corresponding to "green"
(i.e. if you look at the photopic sensitivity function 
that describes how sensitive we are to wavelengths in the visible range 
you will see that the function peaks at a wavelength corresponding to green)
I am guessing that if you were to measure the luminance of the green, red
and blue images (with a photometer), the green image that appeared 
to flicker would be the brightest.