Gemini Watermark Tool is a desktop application that removes Gemini AI watermarks from images using reverse alpha blending.
The tool solves the problem of unwanted watermarks on Gemini-generated images by mathematically inverting the alpha blending equation that creates the watermark, rather than relying on generative inpainting. It uses calibrated reverse-alpha masks for both standard and half-scale watermark variants to reconstruct the underlying image detail. The approach is deterministic and works offline without requiring cloud services or AI hallucination.
The tool suits developers and users who need reliable, reproducible watermark removal without external dependencies. It works as a portable executable with no runtime requirements, making it suitable for automation, batch processing, and pipeline integration. The project offers both a native C++ GUI for interactive use and a command-line interface for scripting. It supports automatic detection and removal of both legacy and Gemini 3.5 watermark profiles, with optional GPU-accelerated denoising for additional cleanup. The README does not compare this approach to alternatives.
Development shows active maintenance with recent updates addressing edge cases. The project added support for free-tier half-scale watermarks with improved detection robustness on complex backgrounds. Support for the Gemini 3.5 watermark profile was implemented with automatic fallback to legacy detection when needed. The maintainer has extended the reverse alpha blending technique to a companion video watermark removal tool, demonstrating continued evolution of the core method.
