Reparametrizing 3D Gaussian Splatting for Real-Time Palette-based Color and Luminance Editing

Professional color editing requires precise control over both color (hue and saturation) and lightness, ideally through separate, independent controls. We present a real-time interactive color editing framework for 3D Gaussian Splatting that supports palette-based recoloring, per-palette tone curves for color-aware luminance adjustment, and pixel-level color constraints. Rather than training a new representation from scratch, we reparameterize the spherical harmonics of a pretrained vanilla 3DGS to encode view-dependent palette weights. We simultaneously solve for weights and palette colors via a loss based on image-space sparsity. Luminance editing is realized as a per-pixel weight shift along the achromatic axis, which we show is equivalent to a per-pixel palette-aware luminance edit. This view-space formulation addresses a core limitation of prior primitive-space methods, where alpha-blending breaks per-Gaussian sparsity and causes edits to bleed into unintended regions. Our edits run in tens of milliseconds via an iteratively reweighted least squares and damped block-coordinate descent that couples tone curves and palette shifts under view-space sparsity. Our representation can be efficiently baked back into a vanilla 3DGS, preserving compatibility with standard viewers. We demonstrate sparser, more localized edits than prior palette-based 3DGS methods, while enabling independent luminance control per palette color and view-consistent pixel-level constraints, capabilities previously unavailable for 3DGS.