Legacy ImageMagick Discussions Archive

Jean-Pierre Coulon wrote:Then is there the right filter for me in grayscale?

Without seeing the original, I can't say.

The original may be printed at a resolution of 6000 dpi, but you are scanning at only 600 dpi. This gives antialiasing: gray pixels at the boundary of black and white.

If you want to save space, try saving the grayscale as JPEG, at different quality settings.

snibgo wrote: ↑2018-06-24T06:51:37-07:00

Jean-Pierre Coulon wrote:Then is there the right filter for me in grayscale?

Without seeing the original, I can't say.

You can obtain a greyscale example by replacing the header of my brief example with P2 50 15 255 and changing all 1 into 255's.
I could have named my topic: Filter to improve some jpg or png images

The original may be printed at a resolution of 6000 dpi, but you are scanning at only 600 dpi. This gives antialiasing: gray pixels at the boundary of black and white.

The jag comes from the irregularity of the paper and printing process

If you want to save space, try saving the grayscale as JPEG, at different quality settings.

I want a monochrome result.

The filter I need should be called -unjag or -dejag

Jean-Pierre Coulon wrote:You can obtain a greyscale example by replacing the header of my brief example with P2 50 15 255 and changing all 1 into 255's.

The result will still be black and white only. It won't replace data that has been lost.

How did you create the black and white version? Please show the exact command. If you dithered, this might account for some of the noise.

snibgo wrote: ↑2018-06-25T01:04:58-07:00

Jean-Pierre Coulon wrote:You can obtain a greyscale example by replacing the header of my brief example with P2 50 15 255 and changing all 1 into 255's.

The result will still be black and white only.

Sure. But some complain about my using tif or pbm.

It won't replace data that has been lost.

Please read again my request: "I would be happy if my 6th line was transformed into0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 "
I am not trying to replace lost data.

How did you create the black and white version? Please show the exact command. If you dithered, this might account for some of the noise.

Simply with a scanner at 600 dpi.