Converting a bunch of pdf files to pnm without loosing resolution

[Andy Green]

Somebody in the thread at some point said:
> On 8/24/07, Andy Green <andy at warmcat.com> wrote:
>> Somebody in the thread at some point said:
>>
>>> Is there any way of converting a bunch of pdf files to pnm without
>>> loosing resolution?
>> What happens when you use the -dpi= option on pstopnm?
> 
> OK, Andy, but how can one find out the dpi's of our pdf file?

Well the pdf is not normally already rasterized in the case of text, so
for that there is no "dpi of our pdf file".  It will render the text
nicely according to the dpi you asked for.

If there are raster images (at various dpi) in the pdf then it will
scale them to the dpi you asked for AIUI.  So I guess you should pick a
dpi that is close to the highest image dpi in the pdfs (eg, 300) and run
with it.

-Andy