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I use the command

convert *.png -flip -page 2647x3745+50+50 doc.pdf

to produce a pdf from scanned images.

I put the option flip in because convert uses the lower-left corner instead of upper-left as reference point. Now I need to flip the pages again.

convert doc.pdf -flip doc2.pdf

Hovever, now the result is very poor resolution (unreadable). Ideally I would like to tell convert to use the upper-left corner instead. I tried -gravity NorthWest but that placed each image with the image upper-left corner in the middle of the page.

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up vote 0 down vote accepted

Try to control the resolution through the density option. If your original scanned document was with a density of 300dpi you can use:

convert -set units PixelsPerInch *.png -density 300 -flip -page 2647x3745+50+50 doc.pdf
convert -set units PixelsPerInch  -density 300 doc.pdf -flip  -density 300 doc2.pdf

the downside is that it will increase the size.
You can obtain an equivalent output even with those 2 lines

convert *.png -flip -page 2647x3745+50+50 doc.b.pdf
convert -set units PixelsPerInch  -density 300 doc.b.pdf -flip doc2.b.pdf
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