OECF 20 Chart (following ISO 14524/15739) contrast 10.000:1, 100.000:1, 1.000.000:1
The former OECF chart contains 12 or 20 gray patches in a circular order and three different patterns in the center of the chart. The current version of the OECF chart skips the center patches due to the sometimes occurring stray light. This chart is also offered as TE264X (D280 format only) where the 20 gray patches are not rasterized as in the standard version of the chart but done with nearly no structure on a very fine grained film.
TE264 version 2 (V2) uses the same data measurements as the original version, but has a different hardware design. The first version of the TE264 uses two plates of glass built around the chart film. On occasion we encountered a few problems with stray light and reflections from the glass. Version 2 replaces the glass with a metal frame, which greatly reduces the chance of stray light and reflections.
The standard size for this chart is D280. We also offer size D240 and D240S on request. As these sizes can be used for multiple illumination devices, we want to ensure you are getting the correct size for your device.