20F On-screen Light Measurement RP

Viewing Projects FCD
last updated: 2020-09-02
contact: Dave Schnuelle



Measuring light on a cinema screen has historically been a process with many variables, which can, and do, cause significant variability in the resulting values. A study group in 20F conducted a year-long research effort and published the "20F-TC On-Screen Light Measurement Study Group Report". This project will implement the recommendations of the Study Group.

Progress Report

1st FCD ballot was approved. Completed 2nd FCD review. Comments being resolved to make ready for 2nd FCD Ballot.

Project Type

SMPTE Engineering Project (ANSI)

Project Overview

Problem to be solved::   There are seven identified SMPTE standard or recommended practice documents that identify or refer to methods of measuring screen luminance. Each document identifies a different specific methodology for measurement. While each of these approaches has some validity, each will result in different measured screen characteristics from the point of view of peak brightness and light distribution. This can cause inconsistency in cinema presentations. The following SMPTE Standards and Recommended Practices specify different ways to measure the light on the screen, or do not specify any method: – S196-2010 Indoor Luminance and Viewing Conditions – RP94-2007 Screen Gain Determination – RP95-2003 Installation of Gain Screens – RP98-1998 Measurement of Screen Luminance – S431-1-2006 Screen Luminance Level and Uniformity – RP431-2-2011 Reference Projector and Environment – RP12-1997 Screen Luminance for Drive-In Theaters
Project scope::   The Drafting Group will recommend a unified approach to screen luminance measurement. There are three different applications of the screen luminance measurement procedure: review rooms and premium cinemas, general cinemas, and 3D. The measurement procedure will apply to digital projection primarily – and recommendations for test patterns, etc. will be focused on digital platforms – but will also be applicable to film presentations. The absolute screen brightness values are not the subject of this RP, but rather the standards that will refer to this measurement method RP.
Specific tasks::   Review the 20F Technology Committee On-Screen Light Measurement Study Group Report on light measurement methodology. Define requirements for light measurement methods (not light levels) for cinema screens. Recommend a single method for on-screen light measurement for 2D exhibition. Recommend a single method for on-screen light measurement for stereoscopic exhibition.
Form of output::   Recommended Practice
Patent Declaration Received? (To be completed prior to FCD):   No


Start: 2015-07-27 | Complete: 2021-03-01 (est.)