5 ms·
That's a 1bit scan saved as JPEG. This should have been saved as 1bit PNG. http://i.imgur.com/2wAcBdL.png http://i.imgur.com/2wAcBdL.png (23.43 KB) For nicer
by ahoge 12y ago
That's a 1bit scan saved as JPEG. This should have been saved as 1bit PNG.
http://i.imgur.com/2wAcBdL.png http://i.imgur.com/2wAcBdL.png (23.43 KB)
For nicer looking images, scan as grayscale and then use Photoshop's Image -> Adjustments -> Curves to turn everything almost-white to white and everything almost-black to black:
http://i.imgur.com/ktj8WkE.png http://i.imgur.com/ktj8WkE.png
Alternatively, do a high-DPI 1bit scan, convert the document to 8bit, and then scale it down.
E.g. when you go from 1600 DPI to 100 DPI, you have 16x16 1bit pixels per 8bit pixel. The result will look smooth and crispy.
- jacobolus 12y ago1-bit images should generally be saved using JBIG2 compression (as far as I know the best lossless compression scheme for 1-bit images), rather than PNG. In some cases CCITT Group 4 compression might be used, for compatibility reasons, e.g. in a TIFF wrapper.
- beagle3 12y agoJBIG2 might be the best compression for bitmap images, but you probably never want to use its lossy mode for text images[0] The fact that a single difference in a configuration bit (lossy/non-lossy) can introduce subtle and easy-to-miss errors (to the point that this went unnoticed by Xerox QA and thousands of their customers!) is an indication to me that while JBIG2 might be superior in terms of the compression it offers, it's not a solution I would use without very serious consideration and deliberation. Just to make this more clear: if you borked the compression setting on jpeg, you get smeared images. If you bork the lossy/nonlossy flag on JBIG2, you get images that look great but may have a random letter or digit swapped for another. [0] http://www.theregister.co.uk/2013/08/06/xerox_copier_flaw_means_dodgy_numbers_and_dangerous_designs/ http://www.theregister.co.uk/2013/08/06/xerox_copier_flaw_me...
- BorisMelnik 12y agothank you! and great tips. the original image was something I grabbed from the web, part of some research. either way really appreciate the tips and the info.