Unwanted Lines after Optimize to Deskew

[Shcomst]

I'm using Adobe Acrobat Pro XI. I have a number of image files that were converted to PDF by a client who inherited them from a gentleman who is no longer with the company. These were large documents that were scanned in slices, then compiled into a single image before being converted to PDF. The PDF's are slightly skewed and no border lines show up between the image slices. If the Adobe Acrobat Edit Text & Images is chosen, each slice of the image can be selected.

The problem I'm having is with the Optimize Scanned PDF command in the Document Processing menu. If I use this feature, the resulting image shows the border between each slice of the image, which is unacceptable. I suspect the image may have been purposely skewed so these faint black hairlines don't show up on the screen. Note that these unwanted lines don't appear when printed to an 8.5X11 sheet of paper on a printer.

Is there any means to deskew an image made of multiple slices and NOT get the unwanted border lines around each slice on the screen view in the process?

[Luke_Jennings]

You could try to open the combined PDF in Photoshop, which will combine the sections into a single image, then rotate (Image> Image Rotation> Arbitrary), then save as a Photoshop PDF. If that doesn't work, you can combine the individual slices in Photoshop using File> Automate> Photomerge. This works really well to combine multiple images seamlessly, e.g. when you take multiple horizontal pictures of a landscape and combine them into a single panoramic image.

[Shcomst]

While that might work for a single page, but it sounds rather impractical for the large number of documents that I have to process when compared to the budget of time available. I was hoping to find a method that keeps Acrobat Pro from introducing the unwanted lines when the document is "Optimized".

[Luke_Jennings]

If my Photoshop suggestion works, you could probably create a Photoshop Action to semi-automate the process.

So you have an image PDF that appears to be made up of multiple image sections, are you sure it was scanned in multiple sections? sometimes an image will get broken up into smaller pieces when a PDF is flattened. This is usually not a big problem unless someone tries to edit the image in Acrobat, or possibly when you tried to optimize scanned PDF. If you are seeing faint white or black lines on screen only, these are stitching lines, which are also caused by flattening, you can confirm they are stitching lines by zooming in on them, if they don't get any bigger, they are stitching lines. Stitching lines are a display issue only. Why are you optimizing? is it to reduce the size? there are other ways to do this that won't flatten the PDF- File> Save as> Optimized PDF.

[Shcomst]

The reason for optimizing was simply to deskew the drawings. This command is the only one I know of in my version of Acrobat Pro XI that will adjust skew. The stitching lines only show up after a deskew and I've tried every combination of optimize settings to prevent them from showing up to no avail. Very frustrating as you can imagine.

The client migrated their proprietary ANSI E size drawings to film initially. Then they went from film viewer technology to an electronic format back in the 90's. The only way to get the resolution called for in their spec with the scanning technology available at the time was to scan each section. If the final version was printed on paper, I could ignore the stitching lines. This isn't the case - they have gone paperless and these drawings are only viewed on monitors.

[Luke_Jennings]

You could turn off the Acrobat and Reader preference- Preferences> General> Page Display> Smooth Line Art (uncheck), which usually causes the stitching lines to vanish, although every person would need to do this on their computer.

This is just a guess, but you could try Tools> Print Production> Preflight> Changes (the blue wrench icon)> Page Contents> Detect & Merge Image Fragments. Do this before Optimize and deskew.

PitStop is an Acrobat plug-in that can rotate pages, I don't know if it will work for you without creating the unwanted lines.

Opening and rotating the PDF in Photoshop, and saving as a Photoshop PDF might be your best option, if it works.

[Shcomst]

The client stated that the first solution will not work as there is no way to enforce this policy on the employees computers. Apparently there's some history of problems with trying to do that. The second proposed solution did not work. Although this did sound like the functionality I was looking for, the fragments are apparently too big or the feature simply doesn't work. I mentioned the PitStop plug-in to the client as a potential solution, but they became rather uninterested when they heard the $799 price tag and I couldn't guarantee it to work.

Thank you for looking into this and identifying ideas for solution. Unfortunately, it appears the only solution is to keep the old-school minor skew so the stitching lines don't appear on the monitor. Rather ironic that the "optimize" command actually does the opposite for this type of PDF by introducing stitching lines, which can't be corrected without using additional software and a significant time investment.

[Luke_Jennings]

If you have access to the original CAD files that were used to generate the film versions, you can possibly save or export them as vector PDFs, which would be ideal. Another way to remove the stitching lines is to export to a TIFF or PNG from Acrobat (File> Export to> Image) this will combine the fragments and remove the stitching lines. You can then open the TIFF or PNG in Acrobat and save-as a new PDF (PNG will produce a smaller file). You can also do this in Photoshop, if you have it. I tested this on a file that had stitching and it worked well, as long as Anti-aliasing is turned off. There are several ways to rotate an image in Photoshop, You could try File> Automate> Crop & Straighten Photos.

[Shcomst · Accepted solution]

The client reported that the original CAD versions do not exist. I'm using Acrobat XI Pro, so there is no (File> Export to> Image). There is a (File>Save As Other>Image), which is apparently the same thing. Unfortunately, this method did not combine the 102 fragments in the PDF either.

I'm aware that Photoshop will stitch images together so they become one. The time it takes to do this process is not available on this project. Fortunately the client is willing to keep the minor skew that hides the stitching lines on the monitor in the final print production.