Earlier we talked about Cineon scans. Converting a Cineon image from its native �log� space to true linear is very simple � just use a transfer gamma of 1.0. In Fusion, this means setting the Conversion Gamma slider to 1.0 (the default). In Shake, this means a DGamma of 1.7 (the slider's value is internally multiplied by 1/1.7, so 1.7 = 1.0. The ProLost definition of �high end� is �needlessly confusing.�).

There's a slight hiccup here, because the results of linearizing a Cineon to g1.0 and then viewing the results through a g2.2 correction are not the same as the results of using a Cineon transfer gamma of 2.2. This means that if you want to round-trip vid and Cineon elements in your comp, you have to choose your definition of �linear� � Cineon�s or video�s.

Welcome to the ConfusoDome�.

In eLin we differentiate between these two working modes with checkboxes for Cineon Emulation.

In the Fusion and Shake workflows, I've differentiated between these two methods with separate sets of Macros.

The straight gamma definition of linear:
eLin_vid2lin
eLin_log2lin
eLin_lin2vid
eLin_lin2log

And the Cineon flavor:
eLin_cin_vid2lin
eLin_cin_log2lin
eLin_cin_lin2vid
eLin_cin_lin2log
eLin_cin_lin2vid.lut

Either one of these systems will round-trip Cineon and vid images safely. It�s just a question of which definition of linear you like better. The straight gamma version is more aggressive, yielding brighter highlights from a Cineon file and with a more precipitous slope near black. The straight gamma version also provides easier back-and-forth with certain 3D apps that support gamma correction but not LUTs (see an example).

Download the Fusion Macros (8kB .rar file)

Download the Shake Macros (32kB .zip file)

Armed with these Macros, you can follow the simple workflow outlined above. Convert vid and log sources to linear, comp away, and convert the results to vid or log for output. In the straight gamma method, you simply use a display correction of gamma 2.2 � easily done in both apps. In the Cineon method you will need to use the supplied LUT file, or create a Shake viewscript from the cin_lin2vid Macro.

This is exactly the color model of eLin, except that eLin packs this whole enchilada into the 15+1bpc color space of After Effects 6.5.

Any questions?