Reduce an image with text makes text blur

Discussions on NConvert - the command line tool for image conversion and manipulation

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Olivier

Reduce an image with text makes text blur

Post by Olivier »

When i use nconvert to reduce the size of a bmp file, i see that text becomes blur.
But when i reduce the size of original picture in MS Word, everything is fine.
I tried to play with "-rtype" : lanczos, mitchell, linear but to no avail.

Any idea ?
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helmut
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Joined: Sun Oct 12, 2003 6:47 pm
Location: Frankfurt, Germany

Re: Reduce an image with text makes text blur

Post by helmut »

Olivier wrote:When i use nconvert to reduce the size of a bmp file, i see that text becomes blur.
But when i reduce the size of original picture in MS Word, everything is fine.
I tried to play with "-rtype" : lanczos, mitchell, linear but to no avail.
When reducing an image with text the text in the image will become blur due to the anti-aliasing. Using a method which does not do anti-aliasing would help, but the results are bad since the algorithm will remove lines and rows of pixels.

Perhaps Word has a better algorithm which is optimized for reducing images containg text, but I doubt that the results in Word are better.

My recommendation:
Here's my personal technique/trick to reduce image with text (typically screenshots):
1.) Reduce the image's size with a good algorithm, e.g. Lanczos
2.) Sharpen the image a bit (Filter->Misc->Sharpen, e.g. 10)

I'm not so familiar with NConvert, so you have to translate this to the appropriate command yourself. Let us know how you go. Perhaps you can post the NC command here.

Greetings, Helmut