new on the M-TLV ISF Calibration Report Version 3
Michael TLV writes:
- The Chromaticity Triangle is now clearly shown on
the scatter graph. The points within the triangle are all the colours that the
NTSC television system can display. This makes it easier to describe to the client about
the coordinate limits.
- A small circle called Close has been incorporated into the graph. It roughly
shows anyone looking at the graph the visual significance of the calibration work. It is a
compromise and a simplification that gives the user a rough idea about their grayscale
accuracy. If the pre-calibration readings are all located within this circled area in
addition to the post-calibration readings, then the likelihood of the client noticing any
visual difference is small. (i.e. Most people probably cannot tell the difference.)
If the pre-calibration readings are located outside of the circle, the before and after
differences in the grayscale should be obvious to most people. This is a simplification at
best because the human eye is actually more sensitive to changes in the grayscale at lower
light levels like the 20/30/40 IRE range compared to 90/100 IRE. The eye is also more
sensitive to certain colours like green and red hence the slight shift of the circle
toward the blue end. Much more blue is required in the grayscale before we can notice a
change. The actual shape of the perception range is more elliptical than the circle shown
on the scatter graph.
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