How do I change default scan settings?

Ah, so are you saying the new computer's running XP, too? If so, same deal. Just remember that you can reach the scanners through start -> control panel -> printers and scanners.

I think it's something deeper in the XP OS than the property settings. Both machines are running XP. I have triple checked that all the usual places where settings can be modified are the same on both machines. I don't think the Canon software has anything to do with it, since I removed it from both machines, rebooted, and experienced the same thing using Windows fax and scan.

I can't really imagine that this is in the OS; if they're both running XP, then that's the same on both machines, too, right? And the OS shouldn't muck about much with the scan-to-PDF function; that's the Canon software's job. Which leaves hardware. Hmm. What software are you using to scan to PDF? Describe the process; are you scanning from another program like Photoshop? Are you just clicking on an icon that says "scan to PDF?" Is there a Canon scanner program?

I had a similar issue with some xerox documate 510s. Solution was to uninstall the software, and then the scanner driver. And then uninstall the device which was "hidden". http://www.tech-recipes.com/rx/504/how-to-uninstall-hidden-devices-drivers-and-services/. After that I downloaded the latest drivers from the xerox. (So this doesn't address the cause, but I figured maybe as a last resort if you needed one).

Do you have Adobe Acrobat V9 installed on your own machine? I noticed that my scans seem to be larger and slower (with the same resolution), since I updated my version of Acrobat. I am wondering if the default PDF conversion settings are somehow different for newer versions of Acrobat. Another thing I noticed is that my scanned PDF files look more bitty/noisy with the new version of Acrobat unless I magnify them to 100% resolution - previous versions looked fine at lower magnifications. There is an optimize function in Acrobat: in the Document menu, select Optimize PDF. You can make the file a lot smaller by trying some of these settings (although some affect the display and print quality - don't overwrite the original scan). There are a set of preset scanning options in Acrobat. I'm not sure if they operate globally or not. (Acrobat settings do tend to overwrite application defaults, so they may). I played with these; they seemed to make some difference to file size but not as much as I hoped. To configure scanning presets (Windows) 1. Choose File > Create PDF > From Scanner > Configure Presets. 2. In the Configure Presets dialog box, select a preset: Black & White Document, Grayscale Document, Color Document, or Color Image. 3. Adjust the settings as needed. 4. Click Save to save the preset, and then click OK.

old PC creates a fast scan with small output file, Are you sure its the same? Stuff like DPI and color depth bit might be hidden from the menus you are used to looking at. Grayscale vs B&W vs color make a difference too. Also your app may scan at the same quality but save at different ones. A jpeg with a quality of 95 will produce and filesize bigger than one at 35. Check those settings too. Not to mention your compression scheme can only do so much. A tiff or jpeg thats a simple black and white document will be much, much smaller than something busy and complex or with a busy background or photo. So if youre used to scanning business type letters and are now scanning photos or things with more graphics then you'll get a larger file size. You can always resave jpegs using Paint.NET or another free editor and shave down their quality settings. Or if you want PDFs you can make PDFs for free with PDFCreator and select the quality level you like.

Maybe there's some http://en.wikipedia.org/wiki/Optical_character_recognition happening? Can you highlight text in the PDF and copy to another document? That could both slow things down and bloat the files (but that shouldn't change file size so drastically, right?