richard@gryphon.CTS.COM (Richard Sexton) (10/20/87)
In article <2538@cbmvax.UUCP> grr@cbmvax.UUCP (George Robbins) writes: >In article <1950@gryphon.CTS.COM> Richard Sexton writes: >> >> [...] The Green phosphor has a shorter persistence than >> either the Red or Blue. > >Sorry, typically green has the longest persistance of the color phosphor >triads. Hmm. Does it make any difference if I say I have a Sony, not a Commodore monitor ? When I draw single pixel horizontal lines in red (15, 0, 0), green (etc) and blue (etc), the green flickers the most. The blue flickers the least. Does this mean my monitor is not 'typical' :-) >George Robbins -- Richard J. Sexton INTERNET: richard@gryphon.CTS.COM UUCP: {hplabs!hp-sdd, sdcsvax, ihnp4, nosc}!crash!gryphon!richard "It's too dark to put the keys in my ignition..."
joyce@hpcehfe.HP.COM (Joyce E. Farrell) (11/03/87)
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.