CurveUnscan is an application that performs curves, charts, or graphs digitization from paper. The digitized data are exported into a file that can be directly read from Excel or any plotting or spreadsheet program. Three different modes are available: automatic, manual, or densitometry. The automatic mode performs curve recognition: the curves are automatically identified, taking into account crossed or dashed curves. The line thickness is also taken into account for better accuracy. The manual mode can be used for digitization of scatter plots or bar charts, for instance. The densitometry mode handles band density, spectrometry, or molecular weight images. The coordinates systems can be linear or logarithmic, orthogonal or not, and may be not parallel to the side of the image (image scanning imperfection). CurveUnscan handles almost any existing image format. Furthermore, the TWAIN support allows to scan images directly from CurveUnscan.