One-dimensional lookup table for simple tonal adjustments like gamma or contrast curves.
Definition
A 1D LUT (1D Look-Up Table) is a one-dimensional lookup table used in digital image processing for color and tonal correction. Unlike 3D LUTs, which process Red, Green, and Blue values simultaneously, a 1D LUT operates along a single axis, influencing only brightness (luminance) or individual color channels in isolation.
The 1D LUT assigns a specific output value to each input value, allowing for targeted gamma corrections, contrast adjustments, or simple color temperature shifts. These tables are particularly efficient for processing Log footage (logarithmic recording) from digital cinema cameras, as they can quickly convert the characteristic curves of different camera manufacturers to Rec.709 or other output standards.
Practical Application
In film production, 1D LUTs are primarily used during the preprocessing of raw footage before more complex color corrections are applied with 3D LUTs or manual tools. They are particularly suitable for standardized workflows where large amounts of footage need to be uniformly pre-processed.
On set, 1D LUTs enable an initial approximation of the desired look on monitors (on-set monitoring) without altering the actual camera data. In post-production, they significantly speed up the conform process.
Technical Details
1D LUTs typically consist of 256 to 4096 data points and require significantly less processing power than multidimensional variants. They support integer and floating-point processing and are available in common formats such as .cube, .3dl, or .csp.