ColorMatrix

ColorMatrix [CMx] is a standard Fusion 2D color node for numerical Red, Green, Blue and Alpha channel transforms. Unlike a LUT or artistic grade, it explicitly combines input components into each output channel using coefficient rows.

The preserved original Inspector shows a five-by-five numeric grid, Update Lock and Invert. No other open menus are captured. The searchable matrix-cell names [row,column] in this guide are editorial coordinates, not invented labels claimed to appear inside the application.

The starting state is a 5×5 identity. The first four rows send R, G, B and A to matching outputs. The final row [0,0,0,0,1] represents the homogeneous coordinate, not a fifth image channel.

Horizontal rows correspond to outputs and vertical columns to input contributions. The fifth column called Add provides the per-channel constants for R, G, B and A. The bottom row is not the ordinary Add-offset row.

For red the model is R_out = m11×R_in + m12×G_in + m13×B_in + m14×A_in + m15. Green, Blue and Alpha each use their own corresponding row. Setting an individual cell to zero or one affects that contribution, not the global tool state.

To exchange red and blue, set the Red output to the Blue input and the Blue output to the Red input, keeping Green and Alpha at identity. Applying the same channel swap twice can restore the original RGB because the transformation is invertible.

For monochrome, repeat an identical input RGB blend in each output color row. A sample 0.2126/0.7152/0.0722 weighting can illustrate a suitable linear RGB pipeline; it is not automatically accurate physical luminance on arbitrary gamma-encoded footage.

A photographic negative uses the separate 1−RGB formula: set the RGB diagonal entries to -1, their Add constants to +1, and preserve Alpha. Intermediate or downstream float values may be negative or above unity even when the eventual display looks clipped.

The Invert checkbox computes the inverse matrix; it is NOT the same as the RGB negative effect. A red scale of 1.25 followed by the same coefficients with Invert on should undo the scale when the matrix is invertible. Singular configurations such as a zero row have no inverse.

Update Lock stops ColorMatrix rendering while several entries are being edited. Release it before comparing the Viewer and exporting; the checkbox is neither a pixel freeze nor a safety lock preventing a user from changing a value.

Alpha is another matrix output like R/G/B. Editing the alpha row changes transparency; using alpha as an input to RGB can change colors near premultiplied edges. On sensitive alpha workflows consider explicit AlphaDivide and AlphaMultiply stages, and inspect edges over contrasting backgrounds.

The optional blue Effect Mask is different from the matrix alpha row: it restricts where the completed transformation appears. A Rectangle mask can isolate a local negative while keeping the matrix alpha row at identity.

Matrix arithmetic can generate values outside the nominal 0…1 interval. Floating-point processing, the Viewer LUT, scopes and export bit depth may display or clamp them differently. Judge the transform using values and scopes, not only the monitor appearance.

This matrix is linear/affine with respect to channel values; it does not replace nonlinear gamma curves, hue operations, HSL qualification or spatial effects. Color Corrector and Color Gain are better for many intuitive creative operations; ColorMatrix is for explicit channel math.

For a reliable test use reference color bars, a gray ramp, a simple spatial mask, the Alpha view and two sequential inverse operations. Change one cell or output row at a time and document numbers to keep the procedure reproducible.

The lesson Flow diagrams are editorial type-checked image/mask connections, not importable .comp files or a native Resolve render. The saved Inspector confirms visible controls, and Blackmagic documentation establishes the transform semantics; a live Resolve 21 verification remains pending.