Image quality issues

[afonit]

The source file is a pdf, that looks great.

I take the pdf on linux and do 'convert -72 to jpg' and the image quality looks pretty dang bad., but if I go to os x with the pdf and open it in preview and save as a jpg at 72 dpi the image is poor but looks pretty dang good.

so the same image converted to 72 dpi, one done it imagemagick on linux/the other in preview.app on os x.

Is there a setting I am missing?



http://img18.imageshack.us/my.php?image=37500391ts9.png

[magick]

Try this command:

• convert -density 400 image.pdf -resize 25% -quality 100 image.jpg

How's that look?

[afonit]

Try this command:

• convert -density 400 image.pdf -resize 25% -quality 100 image.jpg

How's that look?

wow! what a difference., that is perfect, I will play with those settings, I appreciate the pointers.

[anthony]

As a FYI the technique is known as Super-Sampling, and is useful for many image processing techniques.

See Text processing Postscript/PDF
http://www.imagemagick.org/Usage/text/#postscript

As well as general Super Sampling discussion
http://www.imagemagick.org/Usage/distorts/#super_sample