Video Projectors

After the measurements were completed and the review was turned in for editing and posting, I took a second look at the calibration settings. They produced a good grayscale, but they also involved a considerable reduction in the green color-temperature controls, particularly Green Gain (the high end of the brightness range). Since the eye is most sensitive to green, I wondered if I could wring a bit more brightness from the projector by increasing these green settings and adjusting the other controls as needed to maintain an accurate grayscale.

So I attacked the calibration once again, beginning with all the custom color-temperature controls set to zero. Sure enough, the new calibration produced a higher light output. My new settings were:

Contrast: 95
Brightness: 47
White Balance
Gain: Red +19, Green -9, Blue -22
Bias: Red +5, Green 0, Blue -6

Most of the other settings remained the same, though I needed to decrease the Color control slightly and increase the Hue a few clicks toward green for the most natural skin tones.

Following these changes, I took a number of new peak contrast readings with different Advanced Iris and Lamp Control settings (all of them, as before, on my Studiotek 130 screen).

1. My preferred setup:
Iris: Auto1
Lamp Control: Low
Peak white: 16.74fL
Black level: 0.002fL
Peak contrast ratio: 8370:1

2. If you prefer a fixed iris:
Iris: Manual-Max
Lamp Control: Low
Peak white: 15.70fL
Black level: 0.007fL
Peak contrast ratio: 2243:1

3. If you need more output for a larger screen:
Iris: Auto1
Lamp Control: High
Peak white: 25.75fL
Black level: 0.003fL
Peak contrast ratio: 8583:1

4. As in 3, but with a fixed iris
Iris: Manual-Max
Lamp Control: High
Peak white: 24.34fL
Black level: 0.010fL
Peak contrast ratio: 2434:1

The new post-calibration grayscale curves are not shown here, since there were no dramatic changes. The new color temperature did measure slightly higher than 6500K across much of the brightness range, but on average, it was as near to the D65 standard as before.

The main subjective change on real program material was increased light output. The extra 2.5fL in the Low lamp setting was clearly visible. It did mean a slight sacrifice in black level and peak contrast—the change in black from 0.001fL to 0.002fL with the iris at Auto1 is visually marginal, but it does cut the measured contrast ratio roughly in half. Some viewers might prefer the earlier setup, but the new one added significant punch.

In any event, on a larger screen than mine, the added brightness should be welcome. I can also now say, with some confidence, that the Black Pearl is brighter than the Pearl.