DCI Specs - Digital Cinema Initiatives

With the projector turned off or with the lamp-house doused, measure the luminance offthe center of the screen. The ambient light level of a mastering environment reflected bythe screen is required to be less than 0.01 cd/m 2 (.0029 ft-L).For theatrical environments, the ambient light level reflected by the screen isencouraged to be less than 0.03 cd/m 2 (.01 ft-L). Safety regulations and the placementof exit lights or access lights can result in a higher ambient light level. But, it is noted thatthis will reduce the contrast of the projected image.8.3.3.3. Screen CharacteristicsThe screen is required to be non-specular and equally reflective over the entire visiblespectrum. The screen is required to have variable black masking, adjustable to tightlyframe the projected image. This is required to minimally include 1.85:1 or 2.39:1 imageformats. Masking for other formats is optional.8.3.4. Image Parameters8.3.4.1. IntroductionAll image parameters are required to be measured off of the screen from the center ofthe normal seating area in an exhibition theater. The nominal (reference) parametersand the tolerances for review rooms and theaters are summarized in Table 11:Reference Image Parameters and Tolerances.8.3.4.2. Pixel StructureFor the exhibition theater, the sampling structure of the displayed image is required to becompliant with the image and aspect ratio specifications in 3.2 Image Specification.The device structure (mesh) of the projector picture array is required to be invisible atthe reference viewing distance.8.3.4.3. Peak White LuminanceUsing the white field test pattern (X’=3794, Y’=3960, Z’=3890), adjust the peak whiteluminance, as measured at screen center, to 48 cd/m 2 (14 ft-L), with the measurementmade at the reference viewing position.8.3.4.4. Luminance UniformityUsing the white field test pattern (X’=3794, Y’=3960, Z’=3890), align the lamp house tominimize luminance fall-off from center to corners. The measured luminance of thecorners and sides in a 3 x 3 grid shall be at least 75% of the center, as measured fromthe reference viewing position.Follow manufacturer’s recommendations for digital uniformity correction (if applicable).Measure center to corner uniformity as described in [SMPTE 196E].8.3.4.5. Calibration White PointUsing the white field test pattern (X’=3794, Y’=3960, Z’=3890), measure the white pointchromaticity coordinates of the center of the screen with a spectroradiometer.DCI Digital Cinema System Specification v.1.2 Page 82