LPI, PPI,DPI conversions

Here is a conversion chart for DPI (Dots per inch) to LPI (Lines per inch) or PPI (Pixels per inch)

180 DPI................31 lines/inch or 68 PPI
360 DPI................63 lines/inch or 138 PPI
720 DPI................127 lines/inch or 280 PPI
1440 DPI..............255 lines/inch or 561 PPI
2880 DPI..................510 lines/inch or 1122 PPI

If you plan to enlarge your image, it is better to enlarge it when you're scanning rather than in your application. Each time you modify
an image, you lose some quality. Keep in mind when you enlarge a small photo, such as a 35 mm slide or wallet-size photo, you'll need
to scan at a high enough resolution to retain your image quality, but not so high that your file size is too large to be efficient. You must
manually adjust the resolution (dpi) to maintain the same image quality when you resize your image. For example, if you have a 300
dpi 2 x 2-inch image that you want to enlarge to 4 x 4 (a factor of 200%), increase the Scale setting to 200% or change the resolution to 600 dpi.