Gray-Scale Chart And Its Maintenance - Sony CBK-HD01 Maintenance Manual

9-1-5. Gray-Scale Chart and its Maintenance

Use of a reflective-type gray-scale chart (with reflectance
of 89.9%) is recommended for the Gain adjustment. If a
reflective-type gray-scale chart is not available, use a
transparent-type gray-scale chart with a well-maintained
pattern box.
Calibrate illuminance (or luminance) on the surface of the
gray-scale chart to the specified value as follows. Also,
calibrate the color temperature to exactly 3200K by
adjusting the illumination.
Information on the reflective gray-scale chart (16:9)
Availability of reflective-type gray-scale chart
The reflective-type gray-scale chart (16:9) is commercially
available.
Chart : Reflective-type gray-scale chart
(GS-HD of Murakami Color Research
Lab. Inc. or equivalent)
Available from : Murakami Color Research Lab. Inc.
Notes on handling
. Do not touch the chart surface with bare hands.
. Do not rub or stain the chart surface.
. Do not expose or use the chart under direct sunlight for a
long time.
. Do not leave or store the chart in a place that is very
humid or contains toxic gas.
. Do not place anything on top of the chart surface.
. When a chart is stored for a long time without using it,
open the case and leave the chart to dry for 30 minutes or
1 hour once or twice every month.
Guideline of replacing the chart when used as the
reference chart
The reflective characteristics of the reflective-type gray-
scale chart can easily deteriorate over time. As a guideline,
the chart should be replaced every 2 years, but the replace-
ment interval depends on the storage conditions of the
chart.
PDW-700/V1 (E)
Setting Illuminance (In case of using reflective-
type chart)
Measuring equipment :Luxmeter (Minolta T-10 or equiva-
lent, pre-calibrated)
1. Turn on the light source that illuminates the chart and
allow it to warm-up for about 30 minutes.
2. Fix a luxmeter in front of the reflective-type chart.
Obtain an illuminance of 2000 lx uniformly over the
entire surface of the chart by adjusting the position and
angle of the illuminations.
n
Place the light source at the same height and direction
of the camera that shoots the chart surface.
Chart
Luxmeter
Setting Luminance (In case of using transparent-
type chart)
Measuring equipment : Photometer (Minolta LS-110 or
equivalent, pre-calibrated)
1. Turn on the pattern box and allow it to warm-up for
about 30 minutes.
2. Place the pattern box such that direct light does not fall
on the chart surface.
(Alternatively, place a cover the inside of which is
painted with unglazed black, around the entire chart.)
3. Fix a photometer 1 m in front of the chart in the
pattern box.
4. Obtain the luminance of 573 ± 6 cd/m
the chart by adjusting the BRIGHTNESS control of
the pattern box.
n
Adjusting luminance of 573 ± 6 cd/m
illuminance of 2000 lx on the reflective-type gray-
scale chart with reflection of 89.9%.
Chart
1 m
Light source
2
at the center of
2 creates the same
Luminance meter
9-3