The new test film CLT merci-lessly exposes all imaging errors and defects due to inexact fo-cusing, curved screen or oblique projection.
 

Test film CLT with improved contrast
for even more precise focusing

Every movie theater operator wants the best possible reproduction quality. This requires high-quality projection lenses, their exact focusing, the best possible focus equalization with a curved screen and the correct elimination – or at least substantial reduction – of the trapezoidal distortion in the case of oblique projection. SCHNEIDER-KREUZNACH offers excellent projection lenses and accessories such as converters, varioconverters, adapters or the Keystone Converter for this purpose. Precise checking, setting and adjustment are indispensable for the optimum use and utilization of all these means.
 

The test film CLT, on the other hand, has been designed especially for these test and adjustment purposes and provides optimum conditions for a regular check of all relevant quality parameters.
 

Technical Details

This test film is used to ensure the best dimensional accuracy and focus and a calm image steadiness – not as a copy, but only as an original – in lengths of 4 m, 15 m, 30 m and 61 m.
 

All standard formats are presented by boundary lines in accordance with the lat-est and practiced SMPTE standards and are given in millimeters and inches. This allows a precise determination of even very low format differences.
 

The horizontally and vertically extending grid lines allow the recognition of barrel distortion or pincushion distortion (by convex or concave curved lines instead of straight lines); perspective trapezoidal distortion caused by oblique projection (by diverging vertical and/or horizontal grid lines); or geometric distortion caused by screen curvature (by arched horizontal lines) well over what his allowed; the necessary remedies can also be controlled.
 

15 finely graded line grid test groups with a resolution of up to 100 lp/mm (line pairs per millimeter) are distributed over the whole image format. The horizontal and vertical structures are ideally suitable for the optimum focusing of the projection lens and specifically also of anamorphic lenses. The focus distribution can be optimized for the total area in the event of a curved screen or oblique projection. The line grid test groups in the four corners permit an inspection of contrast and focus up to the most extreme corners of the screen even at a format as-pect ratio of 1:2.39.
 

White lines on a black background with an extremely high contrast allows chromatic aberration (color fringes) and scattered light to be recognized easily. This allows a clear distinction between exceptional projection lenses and ones which are not quite so good.
 

Test film CLT