Black and white images (text and line drawings, but not halftone shades of gray or photographs) compress very well compared with grayscale or colour images as very small file sizes can be obtained if the images are saved as TIFFs with CCITT G4 ('fax') compression, or using the newer but less widely supported JBIG2 compression.0kelvin wrote:How much quality do I lose by using maximum compression of black and white pages?
And both types of compression are actually lossless, so there is absolutely no loss of quality despite the very small file sizes that can be obtained compared with files of grayscale or colour images. Those compression methods can be applied directly to image files (although free-standing JBIG2 files are not widely used) or to images contained in a PDF file, which generally adds very little overhead to the total size of the images contained in the file, although OCR'ing the file to make the text contained searchable naturally increases the final file size.
Edit:
JBIG2 compression exists in lossless and lossy versions so naturally only the lossless version is lossless; the lossy version can sometimes shrink files to really small sizes, although when high compression settings are used, at some risk of the misidentification of characters, leading to the possibility of incorrect characters being substituted in the text.