converting jpg to eps using 300dpi resolution

[MOS]

Hi,
I am having troubles using ImageMagick-6.8.8-1 and the convert command.

This works fine:
convert image.jpg -units pixelsperinch -density 300x300 resultimage.jpg
identify -verbose resultimage.jpg
the identify command shows that resultimage.jpg has 300x300 dpi resolution

This doesn`t work:
convert image.jpg -units pixelsperinch -density 300x300 result.eps
identify -verbose result.eps
the identify command shows that result.eps has 72x72 dpi resolution

This doesn`t work either, starting with a 300x300 dpi image:
convert resultimage.jpg -units pixelsperinch -density 300x300 result.eps
identify -verbose result.eps
the identify command shows that result.eps has 72x72 dpi resolution

what is wrong?

[fmw42]

EPS is a vector format and thus has no density. You have to give it a density when you read it in. In this case, you are putting a vector wrapper around a 72x72 dpi raster image. That is why you get 72 dpi from identify.

see
http://www.imagemagick.org/Usage/formats/#ps
http://www.imagemagick.org/Usage/formats/#vector

[MOS]

Thank you for the explanation about eps files.
But, if an eps file doesn't have dpi resolution, why the command identify returns 72x72 dpi as resolution?. I have also applied this command to other eps files and some of them appears to have 300x300 dpi resolution.

[fmw42]

I am not an expert on EPS files. But they are vector files with no dpi. If you imbed a raster image in an EPS and the raster image has some dpi, then perhaps IM is returning the raster image's dpi. Or it sees no dpi and just returns the default of 72 which is assigned to the vector eps.

Perhaps one of the other IM uses knows more about eps files and can correct me or confirm what is going on.