This environment variable specifies the type of film correction used for Cineon files. VizPaint2D works in linear RGB color space while Cineon image files store logarithmic print density space. To correct for this, set the environment variable WF_IMF_CIN_CORRECTION for logarithmic correction when using VizPaint2D with Cineon images.
You set the environment variable to one of the following choices:
off-No data conversion (the data will remain in logarithmic format while editing and on output).
in-Performs film correction only on file input.
out-Performs film correction only on file output.
both-Performs film correction both on file input and on file output.
specific-Performs correction differently on each file. There is an environment variable corresponding to each file sequence. This feature allows a different correction method or density offset to be used for file input and output. See "Correcting specific sequences" on page 484.
Important! When using a Cineon workstation, the display monitor expects film density data to display, so you can turn off WF_IMF_CIN_CORRECTION for image display purposes. |
The Cineon image format accommodates a much wider range of film exposure than conventional computer graphics displays. When processing Cineon images, you may need to adjust the exposure when reading the image (either to shift under- or over-exposed images into a workable range, or to match images with differing exposure levels).
The WF_IMF_CIN_OFFSET environment variable adjusts the image exposure according to the offset that you specify. The offset is a positive or negative integer value in print density units. A value of 90 units is roughly equivalent to one stop. The people supplying the images will know what density offset value, if any, is required.
For example, to bring values down by two stops on input, specify an offset value of -180. This value is added on input and subtracted on output as defined by the environment variable WF_IMF_CIN_CORRECTION.
The offset control is applied while the data is in logarithmic space rather than after conversion to linear RGB space (thus the result is somewhat different than using a pixel scaling operator).
Important! Density offsetting is applied only when film correction is enabled (WF_IMF_CIN_CORRECTION is specified and set to something other than off). If different input and output offsets are required or multiple sequences with different offsets are needed. See "Correcting specific sequences" on page 484. |
Certain motion picture formats (notably VistaVision) record images so that the horizontal plane runs along the film as opposed to the standard formats, which record images across the width of the film. On the resulting film strip, the images appear sideways. Since the Cineon scanner reads the film as recorded, vertical images will appear sideways.
To control this, you can rotate vertical images 90o to horizontal on input and back on output by setting the WF_IMF_CIN_ORIENTATION environment variable. This setting is independent of the WF_IMF_CIN_CORRECTION setting, so you can still rotate images even if you choose not to perform film correction.
To specify rotation, set the WF_IMF_CIN_ORIENTATION environment variable to one of the following choices:
off-Does not rotate vertical images on input and does not rotate to vertical orientation on output.
in-Rotates vertical images on input, but does not rotate to vertical orientation on output.
out-Does not rotate vertical images on input, but does rotate to vertical orientation on output.
both-Rotates vertical images on input, and also rotates to vertical orientation on output.
The default setting for WF_IMF_CIN_ORIENTATION is in, which assumes output will be to a horizontal format. You can also control orientation according to specific sequences. See "Correcting specific sequences" on page 484.
For example, to simply bring in vertical images, process them, and output them to vertical format, WF_IMF_CIN_ORIENTATION can be set to off because processing can proceed with the images sideways.
To input vertical images, combine them with horizontally oriented images, and then output them back to vertical format, set WF_IMF_CIN_ORIENTATION to both (thus rotating on input and back on output). If the rotation overhead is too prohibitive, you can rotate the horizontal images being combined and set WF_IMF_CIN_ORIENTATION to off.