JPG experimenting with density and PDFs
Posted: 2009-10-08T06:55:03-07:00
Hi
Thought I could invite comments on what I'm using imagemagick for:
I have some scanned images of A4 documents that came out rather big .. which is good, I get great detail that way. However, I do want to pack them all into a pdf. I will use pdftk to create one pdf out of several, so the art is all down to rendering a big JPG to a nice A4 PDF.
So, in no particular hurry, I looked at how to best control quality. So one or two questions.
As this will be a 2/3/4 step process, should I choose a non-lossy format as intermediate? I believe there is one such for imagemagick. Using PNG as an intermediate .. I think/believe would be counteractive, yes? Of course, it could be a simple 1 stage conversion if I include all the options on one line properly, whereupon this is a redundant question.
I tried simply reducing the density of these 300x300 Resolution images to 72x72. I was surprised to see only a small change in image byte size. Maybe I shouldn't have been ... because the size is the same, a similar amount of memory is required to store the image, however much the information (i.e. resolution) of the image has reduced. Is that good logic? It's an explanation anyhow.
I am finding it quite empirical right now ... I have to now find suitable resize parameters so that the JPG will convert to an A4 pdf. the "-page A4" doesn't seem to be the whole answer.
Anyhow, thanks for reading. Helpful appreciated.
Thought I could invite comments on what I'm using imagemagick for:
I have some scanned images of A4 documents that came out rather big .. which is good, I get great detail that way. However, I do want to pack them all into a pdf. I will use pdftk to create one pdf out of several, so the art is all down to rendering a big JPG to a nice A4 PDF.
So, in no particular hurry, I looked at how to best control quality. So one or two questions.
As this will be a 2/3/4 step process, should I choose a non-lossy format as intermediate? I believe there is one such for imagemagick. Using PNG as an intermediate .. I think/believe would be counteractive, yes? Of course, it could be a simple 1 stage conversion if I include all the options on one line properly, whereupon this is a redundant question.
I tried simply reducing the density of these 300x300 Resolution images to 72x72. I was surprised to see only a small change in image byte size. Maybe I shouldn't have been ... because the size is the same, a similar amount of memory is required to store the image, however much the information (i.e. resolution) of the image has reduced. Is that good logic? It's an explanation anyhow.
I am finding it quite empirical right now ... I have to now find suitable resize parameters so that the JPG will convert to an A4 pdf. the "-page A4" doesn't seem to be the whole answer.
Anyhow, thanks for reading. Helpful appreciated.