Abt VP30 - Manual (Page 40)

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One is 4 IRE below black (blacker-than-black), one is 1 IRE above black, and the third is 2 IRE above
black. Embedded in the white blocks are 3 bars. One is 1 IRE above white (whiter-then-white), one is
1 IRE below white, and the third is 2 IRE below white. The bottom two blocks differ slightly from these
levels. For the bottom two blocks, the blacker-than-black is at the lowest possible luma level and the
whiter-than-white bar is at the highest possible luma level. When the brightness and contrast are
adjusted correctly, you should be able to see the 1 IRE and 2 IRE above black bars on the black
background and the  ire and 2 ire below white bars should be visible on the white background. When
the brightness is adjusted correctly, black objects should appear ‘black’ with the details still intact
and lighter areas should be ‘light’, not gray, with the details still intact. When the contrast is adjusted
correctly, white objects will appear ‘white’ with the details still intact. Because the contrast settings can affect
brightness settings we recommend that you check the brightness setting after making this adjustment.
NOTE: If you have a CRT based display, following the instructions above may yield a contrast setting
too high. If the contrast is set too high, you will get blooming and loss of details in the highlighted
areas. It is more helpful to use the two vertical lines in the test pattern. Adjust the contrast up and
down and you will notice that these lines will bend as you increase the contrast. To properly adjust
contrast on a CRT based display, decrease the contrast until the vertical lines start to straighten out.
If possible, the two lines should be straight. On some CRT, the lines may not straighten even if you
turn the contrast to its minimum. If this is the case, slowly increase the contrast to a point just before
the vertical lines have extreme bending. You have now properly set up the contrast of your display.
Continue to set up brightness as detailed above.
The ‘Color8 Bars75’ and ‘Color8 Bars100’ will assist in setting up the saturation (color) and hue (tint)
of your display. The ‘Color8 Bars75’ test pattern consists of 8 vertical bars across the screen at a 75%
saturation level. The ‘Color8 Bars100’ test pattern consists of 8 vertical bars across the screen at a
100% saturation level. From left to right the bars are: white, yellow, cyan, green, magenta, red, blue,
and black. To properly adjust the saturation and hue you will need to use the blue colored filter that
comes with AVIA. You will also need to turn off any automatic flesh tone controls on your display before
making these adjustments. When the Saturation and Hue are adjusted correctly, the white bar and the
blue bar should be exactly the same shade when looking through the blue filter. Saturation and hue
settings interact with each other so after making this setting you may want to go back and check that
the saturation setting is correct.
The ‘Gray Ramp’ can help verify that your display is showing the gradients between black and white
correctly. You should see a smooth transition between black and white with this test pattern.
Special Equipment Needed for Display Calibration
To get the most accurate picture on your display, you may want to have an ISF-certified technician
calibrate your display (www.imagingscience.com). To assist in this calibration, the iScan includes IRE
windows to be used with the proper calibration equipment.
Test Patterns Used: Window IRE10
Window ire20
Window ire30
Window ire40
Window ire50
Window ire60
Window ire70
Window ire80
Window ire90
Window ire00
IRE stands for International Radio Engineers and it is a relative scale, NOT an absolute. It defines the
volt peak to peak video divided up into 40 ire units. This is done to make numbers for luminance
levels easier to communicate. In the ISF Training Manual, it is described as the amplitude of the video
signal from blanking (zero volts) to peak white is 0.714286 volts or 100 IRE units. Synchronization
signals extend from blanking to -0.285714 volts or -40 IRE units.