Sony VPL-HW10 Projector Calibration
We calibrate each home theater that is reviewed. It is a pretty standard calibration, there's always more that can be done by some of the "hi-end" calibrators.
12/01/08 - Art Feierman
Sony VPL-HW10 Projector - Color Temperature
Let's start by looking at the color temperature range from white to dark gray, as measured in best (Cinema) mode, right out of the box, without any adjustments. Here are the measurements:
30 IRE (dark gray): 6915K
50 IRE (medium gray): 6820K
80 IRE (light gray): 6630K
100 IRE(white): 6502K
Not bad at all, just a little cool, in the medium to dark ranges.
Below we get into the various settings and adjustments, and report on the grayscale balance, post calibration.
In addition to calibrating Red Green and Blue for a correct grayscale balance (6500K), there are a number of other settings that come into play. Typically Contrast and Brightness (white balance and black balance), should be done first. Color saturation and gamma also need to be adjusted. With some projectors even Tint comes into play, although with most, the Tint control only works with the lower quality inputs (composite and S-video).
Our settings (numbers in parens are the default numbers):
Gamma : Gamma 3 (averages an ideal 2.2 gamma) (gamma 1: 2.0, gamma 2: 1.9)
Contrast: 90 (90)
Brightness: 50 (50)
Lamp Mode: Standard (unless noted otherwise)
Iris: On (we have it off for brightness measurements but on for movie watching)
Color Saturation: 47 (50)
Hue: 50 (50)
Zoom at mid-range, All other settings at default
As you can see, Sony nailed the Contrast and Brightness with their default settings
Sony VPL HW10 Post Calibration Grayscale
The only downside to calibrating the projector, is that you cannot choose to start the calibration from the defaults used for Cinema mode. There are 3 Custom areas, and each starts with a different color temp, but none is as low as the Cinema default, which creates a small problem. When calibrating the Sony HW10, white (100 IRE), basically isn't affected by the individual RGB Contrast (gain) or Brightness (offset) controls.
As a result of that, everything looks really great after calibration, right around 6500K, except for white, which is up around 6900K. This is a small shift, where it doesn't seem to have significant effect.
The end result of our calibration:
White (100 IRE): 6956K
Light gray (80 IRE): 6464K
Medium gray (50 IRE): 6541K
Dark gray (30 IRE): 6541K
We normally just report on those 4 levels of grays, but for this review, here are the measurements of one additional level - 90 IRE - which measured 6412K. As you can see, as soon as you drop down from white (100 IRE), the measurements are all very close to the ideal 6500K.
The inability to have any real effect on white, may not be absolute. We do not calibrate the individual colors - which is the next level of calibration. it's possible that a professional calibrator who gets into that area can knock down the very slight shift to blue of pure white.
Bottom line: While we often get much better post calibration measurements than the Sony (just due to the high value on 100 IRE), based on extensive viewing of the Sony, this slight shift is not impacting the overall image quality in any significant way.
These are the adjustments we made to Red, Green and Blue for the grayscale balance:
Please note, if you are planning on using these - we put these in, in the Custom 2 Color Temp area. Since the starting color temp is different in each Custom Color Temp mode, these numbers WILL NOT work, if you put them in a different custom mode.
Brightest mode: We did not attempt to recalibrate Dynamic mode, as Mike advised me that you can't use the High color temp as a starting point. It is possible that one can calibrate the Standard preset, to get out more lumens, but Mike did not try that.
Remember that the default Dynamic mode is not that much brighter than a calibrated Cinema mode. As mentioned in the Performance section, in the Brightness topic, the calibrated Cinema mode for the HW10 measured 836 lumens, only 37 lumens less than the uncalibrated Dynamic mode. Dynamic mode is very cool with whites not much over 9000K. The Standard mode is much better in this regard, just under 8000K, and a reasonable, if not ideal temperature, for viewing sports, etc.
Bottom Line: Forget the numbers - once we calibrated the HW10, it produced some great looking color. No issues with skin tones which I consider the most important thing. That, no doubt is due to the fact that you aren't working up at 100 IRE when reproducing skin tones.
For those of you familar, here are two post calibration CIE charts. The first is for the settings we recommend, which is to use Standard Color Space. The second CIE chart which is for expanded color space, shows that greens in particular, but also, to a lesser degree, the reds, are oversaturated. We find Standard makes for a better picture.
CIE Standard color space:
CIE Expanded color space:
Here is a bit of an explanation of the CIE chart, and what it shows, provided by Mike:
The color charts used in our reviews is the CIE 1931 color chart from the Commission Internationale de l’Eclairage (International Commission on Illumination), issued in 1931. As you can see, it displays the full spectrum of light with the primary colors of red, green and blue, as well as combinations of those colors to form secondary colors of cyan, yellow and magenta. The combination of all the colors results in the white point in the center. The chart is depicting a two-dimensional slice of what is actually a three-dimensional color space. The x and y coordinates are the chromaticity (defined by Wikipedia as an “objective specification of the quality of a color . . . that is, as determined by its colorfulness” - ie: saturation and hue) values of the colors. Luminance, which is the darker or lighter shades of these colors, accounts for the third dimension of the CIE color space. Obviously, this cannot be shown on a two-dimensional chart.
Typical CIE Chart
HDTV programming has a specified color space which is depicted by the solid white triangle on this chart. The primary colors of red, green and blue form the three corners of the triangle, with the secondary colors of cyan, yellow and magenta appearing at points along each leg of the triangle. Measured values of the primary and secondary colors appear as a dashed triangle on the chart.
If a projector is perfectly displaying the HDTV color space, its measured values of the primary and secondary colors will directly overlay the triangle. As you can see from the chart above, while the blue corner is close to being correct, the red and green points are clearly outside the defined color space. While this is typical of most digital displays these days (many people like a more “colorful” picture, even if it isn’t accurate), it can result in unnatural colors with some sources. This manifests itself as “sunburned” faces and grass that looks abnormally green. Similarly, if the projector’s measured color points resulted in a triangle that was “inside” the solid triangle, this could result in colors that appear “washed out”. One other problem occurs if the color points lie closer than they should to an adjacent color. This can result in a color like yellow looking to green or too red.
Some projectors have color management systems that can help adjust the saturation and hue of primary and secondary colors to their correct points on the charts. While a proper color management system should also include luminance adjustments, even the two dimensional adjustments can make a big difference in providing natural colors.
So, when looking through the reviews, take note of the projector’s color space and, if it’s not correct, whether the projector offers some type of color management or optional color space settings.
OK, that completes our calibration information. Time to discuss matching the Sony HW10 to a good screen, that will work well for your viewing habits, room, and preferred screen size.