This documentation is for version 1.0 of PLogLin (net.sf.openfx.PLogLin).
Convert between logarithmic and linear encoding.
This method uses the so-called “Josh Pines log conversion” or “printing density transform” (as described in http://lists.gnu.org/archive/html/openexr-devel/2005-03/msg00006.html), which is based on a single gray point, rather than the white and black points in the Cineon formula (as implemented in the Log2Lin plugin).
Log to Lin conversion: xLin = linRef * pow( 10.0, (xLog * 1023. - logRef)*density/nGamma )
Lin to Log conversion: xLog = (logRef + log10(max( xLin, 1e-10 ) / linRef)*nGamma/density) / 1023.
|Parameter / script name||Type||Default||Function|
||Choice||Log to Lin||
The operation to perform.
Log to Lin (log2lin): Convert the input from logarithmic to linear colorspace (usually after a Read node).
Lin to Log (lin2log): Convert the input from linear to logarithmic colorspace (usually before a Write node).
|Linear Reference /
||Color||r: 0.18 g: 0.18 b: 0.18||Linear value of the reference gray point. Set this to the linear value that corresponds with the log reference value.|
|Log Reference /
||Color||r: 445 g: 445 b: 445||Log value of the reference gray point. Set this to the log value that corresponds with the lin reference value.|
|Negative Gamma /
||Color||r: 0.6 g: 0.6 b: 0.6||The film response gamma value.|
||Color||r: 0.002 g: 0.002 b: 0.002||Density per code value. The change in the negative gamma for each log space code value. This is usually left to the default value of 0.002.|
||Boolean||Off||Divide the image by the alpha channel before processing, and re-multiply it afterwards. Use if the input images are premultiplied.|
|Invert Mask /
||Boolean||Off||When checked, the effect is fully applied where the mask is 0.|
||Double||1||Mix factor between the original and the transformed image.|