Re: scanning letters
I will scan it as 100 dpi and try several various formats to see which works best.
The best settings for scanning text are:
~ B&W only (aka Monochrome, Lineart) -- this is not grayscale, but rather only black and only white pixels (if you need to scan a pencil drawing, use grayscale, but never color -- unless there is color in there somewhere)
~400 dpi (good), 600 dpi (better), or 1200 dpi (best) resolution-- If your scanner only shows scaling in percentages, than anywhere from 300% to about 1000% should be good
If you save the images as B&W only, the file size will be quite small even at a high resolution. Still, this depends on the format you save it in.
~JPEGs are never good for saving quality text scans in. If scanning in B&W only, try saving the files in either PCX or GIF format. Both of these will save the B&W image with lossless quality while keeping the file size down as well. If neither of these options are available to you, then saving them into a PDF file will work as well.
If scanned and saved in this way, the files will flexible enough to use for PDFs on the web and OCR (text recognition) as well.