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Low resolution when scanning with "Single Scan"


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Hi all,

I use a Canon MX925 and its TWAIN driver to scan paper documents to PDF. When using "Single Scan", Nitro downsamples the resulting scan to 96dpi, even though the scanner resolution in Canon's ScanGear application is set to 300dpi (or 600, it does not matter). When I use a profile (either one of the default or a custom one), this does not happen and Nitro downsamples the document to whatever is set in the scan profile. However, it is a bit tedious to either change a profile or create a new one to make a few changes for a single scan; which is probably why the "Single Scan" method exists in the first place.

Am I missing something? Is there a global setting that defines the output resolution for "Single Scan" documents? Is it a limitation of the Canon driver?

I would appreciate any help.

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  • 6 months later...

It seems I am the only user of this functionality. :( Just in case I am not and somebody else comes across this in the future, I would like to leave some more pieces of information below.

I have collected a few more clues and they lead me to believe that creating a PDF from an image is quite broken in Nitro, irrespective of whether the image comes from a scanner or a file:

  • I need to revise my original observation, the scans from the Canon end up in Nitro as 150dpi images (not 96dpi as I thought before); this happens with "Single Scan" and a scan profile set to 300dpi and it does not matter what resolution I set in the Canon driver (kind of, the scan takes longer with the higher resolution, the result is the same, since the downsampling happens sometime after the optical element).
  • An Epson WorkForce DS-1630 with its particular driver results in the same downsampled images of 150dpi.
  • I have looked for this setting everywhere with no luck. At some point, I got desperate and tested if Nitro's PDF printer settings affected anything (thinking "who knows, maybe the software 'prints' the image to PDF instead of creating it directly"); it does not.
  • If I use the scanner's software and scan to an image at 600dpi (PNG or TIF), correctly tag the image with Xresolution=Yresolution=600, and then create a PDF from these files (carefully making sure that the creation options are set to "custom" and to keep the image resolution), I end up with another PDF @150dpi.
    • I also tried selecting an actual value such as 300 to downsample to instead of keeping the current resoltion. It does not change the result, I end up with an image that is 1/4 the number of pixels in each dimension and has a resolution 150dpi.
  • If I replace the image in this PDF with the same one from disk that I used to create the PDF, lo and behold, I finally manage to have a 600dpi image in my PDF. What a strange and not at all wonderful journey that was.

I have now found a usable workaround, by scanning from my scanner's software to a PDF (at the resolution that I specify, it would seem this is possible after all!) and then open this PDF in Nitro for any additional steps.

Unfortunately, while I was a huge Nitro fan and recommended it to anybody who would listen, this whole problem and my inability to get support from the company (since I did not have an active support contract and could not buy one when I upgraded to version 12) has left me kind of disillusioned and I will start to look for a serious alternative; I am also going to recommend to friends and family to look for a PDF tool somewhere else.


Edited by l-c-g
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I've got the same problem.. It wasn't always like this but has been so for awhile. I just don't have time to maneuver the complicated user account sign-in community forum to report it.  

I have been using an old Brother MFC-7820N for 11 years.. Been working great until I broke the hinge on the ADF recently.. Just setup a new HP Color LJ Pro M281fpw and it has the same  exact problem.. I hit the "PDF From Scanner" button from Nitro's PDF menu and I get a poor quality scan..  I create a profile with the exact same scan settings as the default and it works fine. I get a nice quality scan but I have to open the PDF menu and choose the profile every time..  This is too time consuming.  

I would like to know how to adjust the default scan profile settings..   99% of the scanning I do is grayscale, 300dpi so I need to set the default scan to do this..   This wasn't a problem in earlier version of Nitro Pro but since upgrading to 11 or since the interface was changed to resemble a  Microsoft Office ribbon bar it's been a pain in the butt to use for scanning. 

Where do I change the settings for the default scan profile?  If I can't fix this I'm going to search for alternate software for scanning.  I've been a Nitro Pro user for 15 years.   I've uninstalled and reinstalled NitroPro and it doesn't address the problem. 



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  • Official Nitronaut
Allain Umailin

Hello @Buster Scruggs @l-c-g,

Thank you for reaching out to us through our Community Forums!

To further assist you with your concern, I created support tickets on your behalf.

I will wait for your responses through the support case.


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  • 2 weeks later...

I appreciate the support incident but there was not nearly enough time to respond to it before it was closed and no one has responded back from efforts to reopen the case.   The problem is not resolved and I have taken my time to submit a significant amount of information through the support incident process as requested. 

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