Cineon Insert Node

The Cineon Insert node converts raw Cineon film data to Cineon Linear format. "Cineon Linear" refers to 10-bit log data that has been converted to 16-bit or floating point linear using the "insert" method, which remaps the Cineon 90% white point to 90% white in linear space (e.g., 4095 in 16-bit) to preserve any highlight data above the white point.

Cineon log files are usually converted to a linear format when they are loaded into a Disk Input node. However, this conversion can be disabled when you wish to work with 10-bit log data. If at some point later in the network you wish to work with Cineon Linear, you can use the Cineon Insert node to perform the insert method of conversion on the log data.

Note:
To convert Cineon 10-bit log to any other format, such as 8-bit linear or straight 16-bit linear, use the Bit Reduce Node .

Cineon Insert Parameter Tab

This tab provides controls for the Log 90% White card, the Film Gamma, and the Linear 90% White code value. These parameters provide control over the shape of the conversion curve. The defaults are based on Cineon specifications.

Convert

This menu enables you to select whether to convert to integer (16-bit) or floating point data. This will not affect the conversion process itself; instead, it determines how the output values will be interpreted.

Log 90% White

The Log 90% White parameter enables you to set the values of the 90% white card, which is used as the reference for a relative log exposure of 0 in 10-bit log space. The default value is 685.

Film Gamma

The Film Gamma parameter enables you to set the conversion values for film gamma, which controls the straight-line portion of the characteristic curve for typical negative film. The default value is 0.6.

Linear 90% White

The Linear 90% White parameter enables you to set the values for the 90% white code in the conversion to linear color space. The default value is 4095.

The above parameters contain different entries for the Red, Green, Blue, Alpha, and Other parameters, enabling you to vary the conversion from channel to channel. If you wish to enter a value into all parameters, key the value into the Red parameter and click on the Cascade button. You can also suppress an operation at a given channel using the Channel Mask buttons.

About the Conversion Algorithm

The Log 90% White, Film Gamma, and Linear 90% White parameters specify certain variables in the conversion process. The operation involves a scaled, adjusted inverse log of the logarithmic (base 10) input data:

OUTPUT = 10^((INPUT - Log 90% White) * Film Gamma / 0.002) * Linear 90% White

The above equation is based on the algorithm provided in "Conversion of 10-bit Log Film Data To 8-bit Linear or Video Data for the Cineon Digital Film System," published by Kodak Motion Picture & Television Imaging.

For more information on the Log 90% White card, Film Gamma, and the Linear 90% White code value, see either the document referred to above or "Grayscale Transformations of Cineon Digital Film Data for Display, Conversion, and Film Recording," published by the Cinesite Digital Film Center.

Both of these documents are available for downloading from the Silicon Grail website (www.sgrail.com).




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