Colorspace Converter

The Colorspace Converter allows for converting between a wide range of different colorspaces, white points, and transfer functions. If we don't have support for a particular colorspace or transfer function, please reach out to us and we'll try our best to add it in the next release.

Usage

The first row, labeled "Source" should describe the the current Colorspace, White Point, and Transfer Function and the second row, labeled "Destination" should describe the target Colorspace, White Point, and Transfer Function. You can optionally disable either the Colorspace + White conversion or the Transfer Function conversion.

Bradford Matrix

The Bradford Matrix is a "chromatic adaptation" matrix that is mostly only useful for color scientists. It makes the result of the conversion look the same as the original when viewed in the same display/illuminant. So instead of the same XYZ values in a different colorspace, it alters the XYZ values to make the result match the source when viewed in the new target illuminant. If you apply a Bradford matrix (say D65 to D50) but you don't convert to D50 when you go back to RGB and you stay at D65, it will look as if it were exposed by the D50 illuminant. Essentially you are white balancing the shot. The Bradford Matrix is normally only used by people who know they need to use it.

Auto Adjust Scene Minimum

Often times Camera Log encodings will have different scene-minimum values due to the different ways the camera manufacturer handle their camera's noise floor. Enabling this adjustment offsets the scene linear data so that the minimum value of the source function matches the destination function.

Copy to Clipboard

For the more technical users, you are able to copy to the clipboard the transformation matrix based on the Primaries + White Point selection, the source NPM, and the destination NPM.

Warnings

Whenever Lattice thinks you shouldn't perform a certain kind of transformation, a warning icon next to the transfer function checkbox will appear. These warnings will not prevent you from performing the conversion. There are two types of warnings. One warning is for converting from Scene Linear to a Camera Log space when the LUT's input bounds don't encompass the full Scene Linear dynamic range of the Camera Log format in question. The other warning is for when you attempt to convert between display-referred and scene-referred spaces - converting between these spaces should strictly involve a creative tonemap as there are no real technical conversions between these two types of spaces.

Examples

Below are some example situations you might run into when converting between different spaces.

Converting from a Camera Log to Rec 709

This is one of the most popular questions we receive. There is no standard technical solution for converting between Camera Log (scene-referred) and display-referred space. In most cases camera manufacturers will provide their own conversion LUTs which contain creative tonemapping and usually some sort of colorspace conversion. If you want to hijack a certain camera manufacturer's tonemapping strategy for a different camera, you certainly could do that. For example, if you wanted to convert Blackmagic Film 4.6K to Rec 709 via Arri's standard Log C to Rec 709 LUT, you would do this conversion:

From there, you would just need to combine Arri's Log C to Rec 709 LUT on top of this LUT by either simply dragging the LUT from a Finder window into the LUT window, the "Combine" button in the toolbar, or Edit -> Combine -> Combine. 

Converting to DCDM-X'Y'Z' for Digital Cinema Packages

This is as simple as setting your source and selecting "DCDM-X'Y'Z'" as the destination colorspace - the rest of the settings will automatically be filled out. If you were grading on a calibrated monitor for Rec 709, you will most likely use Rec 709 / D65 / Gamma 2.4 as a source. If you were grading with a calibrated cinema projector, you will most likely use P3 / DCI White / Gamma 2.6.

You can easily perform a reverse transformation (Converting from DCDM-X'Y'Z' for viewing on a non-DCDM compliant device). You would just set your source as "DCDM-X'Y'Z'" and destination (for example) as Rec 709 / D65 / Gamma 2.4 for a Rec709 calibrated monitor, or P3 / DCI White / Gamma 2.6 for a P3 calibrated cinema projector.

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