pdf to png text thickness

[TreborAlmasy]

So after searching through google reading all the documentation and trying just about every combo of 'filter' and 'blur' and 'unsharpen' I'm out of ideas.
Essentially what I'm trying to do is get the imagemagick preview of a pdf to look like photoshop:
Photoshop:


ImageMagick:


All that was done in photoshop was a simple resize, with bilinear interpolation.

I read... somewhere... that photoshop applies a sharpening mask after a reduction in size, but that just seems to make things worse in imagemagick. I tried all the examples in the 'help section (http://www.imagemagick.org/Usage/filter ... downsample), but none really even came close to photoshop.

[snibgo]

Have you played with "-density"? That's the most important option for getting quality from a pdf.

[fmw42]

As user snibgo suggested, try

Code: Select all

convert -density 288 image.pdf -resize 25% image.jpg

density 288 = 72*4 (four times nominal 72 dpi) so we are getting 4 times the quality from the pdf

So we resize by 1/4=25% to get back to nominal size. If the size is not quite correct, either adjust the density or the resize percent. Or just resize to whatever size you want.

[TreborAlmasy]

I had the density set to 330, but it still wasn't working.
BUT when I moved the density to before the 'image.pdf' it worked like a charm.
Huzzah!
Thanks for the help guys.

[fmw42]

Vector files such as pdf, eps, etc have no size until you read them in. But you need to specify the density before reading them so the reader knows what value to apply. Raster images have a size and density is used afterwards simply to apply a setting in the file so that printers know how to translate pixels to physical dimensions such as inches or centimeters.

[TreborAlmasy]

Ah, that actually makes sense.
Is that in the documentation anywhere? Because I searched for HOURS trying to figure out what was causing the issue with no luck (or examples) to go on.

[snibgo]

http://www.imagemagick.org/script/comma ... hp#density says: "This option specifies the image resolution to store while encoding a raster image or the canvas resolution while rendering (reading) vector formats such as Postscript, PDF, WMF, and SVG into a raster image."

I think some words could be added to the effect that "-density" should be set before the read or write.


http://www.imagemagick.org/Usage/basics/#density says: "You can set the resolution or density of an image as it is being read into IM by using the "-density" function, before reading or writing the image, or using "-set density" after reading the image. "


A search in these forums should also have helped. When I read the list of questions and see one about PDF, I automatically think, "The answer is to use density."

[fmw42]

Something about -density should be mentioned in http://www.imagemagick.org/Usage/formats/#ps, but it is now. But the link to http://www.imagemagick.org/Usage/text/#postscript does have some information about supersampling there.