HDR Compander effect
The HDR Compander (compressor/expander) effect gives you a way to work with tools that don’t support high–dynamic range color—such as 8-bpc and 16-bpc effects—without sacrificing the high dynamic range of footage.
The HDR Compander effect works by first compressing the highlight values in the HDR image so that they fall within the range of an 8-bpc or 16-bpc image, and then expanding the values back to the 32-bpc range.
Apply the HDR Compander effect to a layer once before working with low-dynamic-range tools and effects. Then, when you’re finished, use the HDR Compander effect to expand the dynamic range back to 32 bpc.
Because the first instance of the HDR Compander effect compresses the range of values through sampling, some precision is lost. For this reason, use the HDR Compander effect only if you’re willing to trade off some precision in values for the sake of high dynamic range.
This effect works with 8-bpc, 16-bpc, and 32-bpc color.
Apply the HDR Compander effect
- Apply the HDR Compander effect to a layer in a 32-bpc project.
- Select Compress Range for Mode.
- Set Gain to the maximum value to be represented in the compressed range—that is, the highest white value in the image. Don’t set Gain too high; the more of the 16-bpc value that you use for highlights, the more compressed the midtones (the majority of the pixels) will be, and the more data will be lost in this process.
- Set Gamma. Gamma affects the distribution of values in the range, allowing more precision in specific areas of the range.
- Apply whatever low-dynamic-range effects you choose to the layer.
- Apply another instance of the HDR Compander effect to the layer. Make sure that the second instance of HDR Compander is ordered after (below) any 8-bpc or 16-bpc effects you’ve applied.
- Select Expand Range for Mode for the second instance of the HDR Compander effect.
- Set Gain and Gamma to the same values as set in the first instance of the HDR Compander effect.
A more convenient way to use the HDR
Compander effect is to apply the Compress-Expand Dynamic Range animation
preset. This animation preset consists of an expression and two
instances of the HDR Compander effect: The first instance has Compress
Range selected, and the second has Expand Range selected. The expression
automatically sets the Gain and Gamma for the second instance to
be the same as that which you set for the first instance. Insert
whatever low-dynamic-range effects you choose between these two
instances of the HDR Compander effect.
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