We have had some test scans made of a pressed flower album, and are mightily puzzled by the difference in quality when we process the resulting JPGs through BookReader. There are 2 batches, each taken by different 3rd parties.

For Batch A, the original JPGs are ~3-4MB each, 1524 dpi, 24 bit depth. When passed through the BookReader, the resulting JPGs are ~20-25KB, 150 dpi, 24bit depth.

For Batch B, the original JPGs are ~700KB-1MB each, 200 dpi, 24 bit depth. When passed through the very same BookReader, the resulting JPGs are ~80-85KB, 150 dpi, 24 bit depth.

For Batch A, the quality when viewing in the BookReader is atrocious. Not surprising, I guess, given the resulting files are so small. Batch B comes up 'OK' in the BookReader.

What I can't figure out is why is it that Batch A comes out most poorly after being processed by BookReader, given the original file sizes and resolution are so much larger than Batch B. Can anyone shed any light?

When I look up the exif data of the files, Batch A has a compression factor of 6; while batch B is 1. Could this have anything to do with it?

Thanks.

Bernadette Houghton
Digitisation and Preservation Librarian
Library
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