Hi Kyle, not a misprint. But I may have been a bit obscure. The original JPGs (of 1524dpi etc) were converted into PDF (using default settings); and it was from this PDF that the lower quality JPGs were derived. This same process was used for both Batch A & B.

Bern

-----Original Message-----
From: Code for Libraries [mailto:[log in to unmask]] On Behalf Of Kyle Banerjee
Sent: Thursday, 26 May 2016 9:20 AM
To: [log in to unmask]
Subject: Re: [CODE4LIB] JPEG question

Is that 1524 dpi for Batch A a misprint? If not, that's very likely to be your problem -- I doubt that's what the vendor really scanned at.

If you change the dpi values and try to reload, my guess is you'll get very different results.

kyle

On Wed, May 25, 2016 at 2:40 PM, Bernadette Houghton < [log in to unmask]> wrote:

> 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
> [Title: Deakin University logo]
> Deakin University
> Locked Bag 20000, Geelong, VIC 3220
> +61 3 52278230
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> >
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>
>
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