PoliBrush is a freely distributed, stand-alone software designed for teaching exploratory multivariate analysis in the frame of color RGB and spectral imaging. PoliBrush implements principal component analysis (PCA) as its core method. It features a single main window that provides users with essential tools for spectral image preprocessing and exploration. The software emphasizes an interactive brushing approach, enabling users to gain a comprehensive understanding of the relationships between PCA score space and image pixel space. Example datasets can be downloaded from: XRF-HSI Vermeer dataset 10.5281/zenodo.8143464 NIR-HSI Venus dataset 10.5281/zenodo.8143550 A detailed user guide is provided in the following open-access tutorial paper: R. Rocha de Oliveira, C. Malegori, G. Sciutto, P. OliveriPoliBrush – A user-friendly software to aid multivariate image analysis disseminationChemometrics and Intelligent Laboratory Systems, 240 (2023) 104918https://doi.org/10.1016/j.chemolab.2023.104918

Financial support provided by Università degli Studi di Genova (Research Project Curiosity Driven 2020: "3Depth – From 2D to 3D hyperspectral imaging exploiting the penetration depth of near-infrared radiation", CUP: D34G20000100005) is gratefully acknowledged.