[build 403 bug] Adaptive compression results in blank page

[Mathew]

When using "enhance scanned pages" I'm getting a blank page if I use adaptive compression on a page scanned in color:

image.png

results in (the redacted/blurred portions remain):

image(1).png

adaptive compression bug.pdf

[Sean - PDF-XChange]

Hi Mathew,

Could you please clarify what your goals are with enhancing this page? If it's merely to perform OCR and remove the blotches then you can do so with the OCR feature's "Fine Page Content" option:

image.png

I hope that helps,

[Mathew]

This is just part of a scanned document. My goals are to reduce the file size and ocr. With a document that is mostly black text and some color marks I get large reduction in file size using mixed raster compression on other software. I’m assuming Adaptive compression is PXCE name for MRC and it used to work in previous versions of PXCE

Related post viewtopic.php?p=179735#p179735

Scanned file size is important for many reasons in my mind:
- storage
- emailing/sharing of files
- speed of file opening/saving

[Sean - PDF-XChange]

Hi Mathew,

Okay, thanks. The steps detailed above should take care of the OCR component for you. As far as compression goes, have you tried using the Save as Optimized feature? You may find what you need there:

image.png

Kind regards,

[Mathew]

Thanks for the workaround Sean: I do need to set it to MRC though to get good compression:

image.png

I look forward to a fix because the workflow Scan > OCR > Save as Optimized > Open optimized file (to check it) is a bit roundabout.

[Mathew]

Sean,

A side note as I see in your footer "Technical Writer": In the online manual, it mentions "Adaptive Compression" only in this feature, but does not define it:
https://help.pdf-xchange.com/pdfxe10/en ... ompression
and in the save options, it does not mention MRC:
https://help.pdf-xchange.com/pdfxe10/sa ... ns_ed.html
although there is a very useful tooltip on the actual option:

image.png

So maybe "Adaptive Compression" is something else and I made a wrong assumption it was MRC? Anyway, for now I'll not use "Enhanced Scanned Pages".

Mathew.

[Sean - PDF-XChange]

Hi Mathew,

Thanks - I'll take a look into that in due course.

Kind regards,

[Sean - PDF-XChange]

Hi again Mathew,

I had some input from the development team on this. When the Adaptive Compression box is selected, it results in using MRC for page images before using compression. The image is separated into multiple layers: a background layer (for images and colors), a selector/mask layer (a high-resolution binary layer for text contours), and a foreground layer (for text color). Different compression algorithms (e.g., JPEG for background, JBIG2/TIF G4 for masks) are applied to each layer to optimize file size and quality. If the Adaptive Compression box is not selected, then PDF-XChange Editor will just use the compression settings that you specify in the Enhance Scanned Pages dialog box, without using MRC to separate images into multiple layers before being compressed.

I hope that clarifies things for you, and thanks for the feedback - I will update the manuals to include this information to ensure that everything is clear for users from now on.

Kind regards,

[Lyxius]

Hi,

I encountered the same Problem today as described by Mathew. When using the Adaptive Compression you get an empty page.

After searching a while i think the culprit is the Blend Mode under Page Content Properties.
Since Adaptive Compression uses multiple layers and the Blend Mode stays at Normal, it only shows one layer.
By changing it to Multiply you can see the text and pictures again.

I don´t know if this is indeed a bug or intended to work that way.

[Sean - PDF-XChange]

Hi Lyxius,

Could you please share the problematic document here so that we can take a look?

Kind regards,

[Lyxius]

Hi,

thanks for the quick reply. I attached two files. Document1 is affected by the issue and by changing the Blend Mode to Multiply everything looks good. Document2 contains mostly text and for some reason it works perfectly fine without any changes.

1.png

2.png

3.png

Document1.pdf

Document2.pdf

[Sean - PDF-XChange]

Thanks for that Lyxius, I passed this issue on to the development team for review. They have confirmed that a bug is present and a ticket has been created:

Ticket #7762: Blank Pages Created when Using Adaptive Compression

Kind regards,