Frequently Asked Questions

Where Optical Character Recognition is to be applied to text-based material, the minimum recommended standard is 8-bit greyscale at 300 pixels per inch.  Where text is very small a resolution of 400-600ppi is recommended.

If the images are being created to preserve significant detail above and beyond Optical Character Recognition, the following formats and standards are recommended:

For sources containing text with colour illustrations or backgrounds: TIFF or JPEG2000, resolution of 300 ppi, bit depth of  24bit, with no compression or  lossless compression.

For sources containing text with black-and-white illustrations (pictures or shades of grey): TIFF or JPEG2000, resolution  of 300 ppi, bit depth of 8bit, with no compression or  lossless compression.

For sources containing text with or without line drawings: TIFF or JPEG2000, resolution 600 ppi, bit depth of 1, with no compression. If compression is necessary for storage purposes, lossless is recommended.

For more information on standards, see the Image Capture chapter in the IMPACT Decision support tools:  <available shortly>

For more information on digital storage, see the IMPACT Storage Estimator (ISE).