When you choose 45-bit image files, image data are stored in individual files with .tiff extensions (double f). These are TIFF (Tagged Image File Format) files with 48 bits per pixel - 16 bits per color. Only the most significant 15 of the 16 bits are used to store image information. The least-significant bit is used for housekeeping information such as noting which areas of a warped image do not correspond to areas of its original, unwarped image.

When you choose 24-bit image files, image data are stored in individual files with .bmp extensions. These are Windows device independent bitmap files with 32 bits per pixel - 8 bits per color. Only 24 bits of each 32 are used to store image information. The additional 8 bits are used for housekeeping information such as noting which areas of a warped image do not correspond to areas of its original, unwarped image.

Color data stored in .tiff files within the project remain unaffected by color correction values. That is, the color correction values affect only the display of the .tiff files.

When you save image files with the Salva immagine corrente con nome... / Save current image as... command (File / File menu), BMP and JPG files are always color corrected.  For TIFF and PNG formats, you may choose to store corrected or uncorrected colors.  See the Impostazioni TIFF / TIFF settings dialog box and the Impostazioni PNG / PNG settings dialog box for more information.

Images with uncorrected color information are probably unsuitable for printing or importing into other applications.