Jeff Pugrant of J. Pugrant Staging and Design tells us that Avid will again be using DPI projectors to create a 5' X 23' display. The image will be created with 4 HIGHlite Pro series, 12000Dsx+ units.

Our good friends at Vista Systems will be installing several of our HIGHlite Pro 12000Dsx+ units as well as our new HIGHlite Pro 12000HD units. Both platforms will be configured in a seamless array to show off Vista's SPYDER system. This will be the first time DP's 2K HIGHlite HD's will be displayed at a major trade show.

Digital Projection is pleased to announce we will soon commence shipping Mercury HD (single lamp) projectors with a new yellow notch filter that improves color gamut and reproduction.

Why is this yellow notch filter important?

All current products within the Mercury lineup employ Metal Halide lamps as their illumination source. These lamps deliver many benefits, including longer lamp life, exceptional lumen per watt efficiency, and low cost of ownership. Metal Halide products are generally very suitable for business and high use applications.

However, the compromise in using a metal halide lamp is that they produce low red and yellow spectral energy, as compared with the broad spectral output of a Xenon lamp. Typical comments from customers comparing our Mercury products with our Xenon lamp-based projectors, like our HIGHlite series, are that the skin tones aren't as rich and that yellow and gold tones don't seem as deep.

To optimize our Mercury products for critical color applications, such as Home Cinema venues, Digital Projection's engineers have designed an improved optical engine incorporating the new yellow “notch” filter. This special optical filter corrects the spectral performance of the Metal Halide lamp, while sacrificing minimal projector lumens.

DPI tested numerous Mercury projectors, both with and without the yellow notch filter. In all cases, the native color temperature was corrected by roughly 1200° K, while light output was reduced by only 2%.

This benefit of this color correction will be most noticed when viewing video and HD content, as this material is produced with an intention to be presented on displays with native color temperatures of 6500° K (DVD movies are one example). The yellow notch filter increases the separation between red and green, enabling better reproduction of skin-tones and a slightly wider overall gamut. It also makes saturated reds and green foliage look far more realistic. Although this performance still does not quite match that of a Xenon-based system, it greatly improves the accuracy of color reproduction while still retaining the metal halide benefits of lower cost and longer lamp life.

Optimizing the lens aperture on DPI's new dVision Series Projectors

Every lens for Digital Projection's dVision sx+ and dVision HD projectors includes an internal motor driven aperture that can be remotely adjusted to optimize the balance between projector light output and contrast for a specific venue. In practice, the effect of this aperture is simple: When in its maximum open position, the projector's full brightness is transmitted through the lens and onto the screen. As the aperture is incrementally closed, the projector's brightness and optical scatter light are clipped, resulting in lower lumens but rewarding with significantly reduced black level and a higher contrast ratio.

When using a dVision projector in a high ambient light environment, the proper setting for the aperture is its maximum open position. The reason is that projected imagery in high ambient light venues will not benefit from a projector with high contrast (low black level), but will benefit from maximum lumens. Indeed, in high ambient light environments, the only way to increase the environmental dynamic range of the image is to either turn out the lights, or bring as many lumens to the table as you can possibly muster. Thus, for high ambient light environments, beyond assuring the aperture is fully open, you may also want to run both of the dVision's lamps at full power. Depending on the content being displayed, you may even want to add some white boost and select one of the more dynamic gamma presets.

However, in venues with high control over ambient light, the benefits of the adjustable aperture really come into play. The darker the venue, the more an image with ultra low black level and high contrast can be appreciated. In theatrically dark venues, once a minimum threshold of projector lumens is achieved (enough to produce 12-16 Ft. Lamberts of light as reflected by the screen), screen black level and contrast ratio become a dominant factor in creating superior image quality.

Follow the simple procedure below in venues with low or theatrically dark ambient lighting:

•  Set up the dVision as you normally would, starting with both lamps on "High" and white boost "Off" or set to a minimal level.

•  With the room lighting set to typical viewing conditions, display a test pattern or a static source that exhibits both 100% white and 100% black content, as well as a range of intermediate shades. Select the projector gamma and set colorimetry to your preference. Adjust projector brightness and contrast accordingly.

•  If the image is far too bright for the venue, reduce lamp power on both lamps, or turn one lamp off. Adjust lamp brightness until the image is still somewhat brighter than you need it to be. Re-check colorimetry and gamma if necessary.

•  Finally, start closing the aperture while carefully watching the black level in the 100% black content area of the image. Optimally, you want to achieve zero black level (no visible illumination in the black content) while still projecting enough lumens to produce the target Ft. Lamberts required for the venue. If in your search for “perfect black” the projector brightness drops too low and you can't achieve your target Ft. Lamberts, re-adjust lamp power and/or turn on both lamps.

You may need to go through the cycle a couple of times before you strike the perfect balance between screen brightness and black level. The goal is to produce perfect black and your target Ft. Lamberts while running one or both lamps (as necessary) at the lowest possible power. Lower lamp power equals longer lamp life, so by following this process, you not only achieve the optimum balance between contrast and brightness for the venue, but you are further rewarded with the lowest possible operating cost.

Tech Tip Archive

Demo Program: Commercial AV Dealers:

• Dealers and Special Contractors may purchase up to two demo units per calendar year
  
• Demo units may be purchased at 5% off of DPI's published end column Commercial AV dealer pricing
  (End Column x .95)
  
• Excluding iVision, which already comes standard with a lens, the 5% demo discount may also be applied
  to (1) projection lens for each demo projector purchased
  
• Dealers in good credit standing receive standard payment terms - 2% cash with order, 1% 10 days, net
  30 days

December 2004
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