How to check PDF DPI

[Pravin]

Hi ,
I am using the html2pdf PHP lib. to create PDF file which contents
text and images.
I want to check DPI of that generated PDF.
is there any tool or way to check that

Thanks
Pravin.

[Robert Kochem]

Pravin wrote:

PDF is in general an vector format and is therefore not affected by the
"resolution-problem". Only embedded images, bitmap fonts and similar things
have their own resolution. But that is individually to each embedded item
and does not apply to the pdf itself.

Robert

[Bernd Alheit]

You can check the resolution of images with the Preflight Tool of Adobe
Acrobat.

[booklover]

Robert (and other PDF experts ... ),

I have heard that said before -- PDF is resolution independent -- but
I haven't quite understood that.

Here is what is confusing me.

On my PDF software export, I have 3 options:

Highest quality (for hi-quality printing)
Laser printing quality
Smallest size (for viewing PDF on the web)

Most of my documents in PDF have NO images; so what is the difference
between these three versions of PDF -- if that difference is not
"resolution" ?

This problem has been confusing me for a long time !

Thanks very much,

RW

[Peter Flynn]

booklover wrote:
> Robert (and other PDF experts ... ),
>
> I have heard that said before -- PDF is resolution independent -- but
> I haven't quite understood that.
>
> Here is what is confusing me.
>
> On my PDF software export, I have 3 options:
>
> Highest quality (for hi-quality printing)
> Laser printing quality
> Smallest size (for viewing PDF on the web)

This probably refers to images only.

> Most of my documents in PDF have NO images; so what is the difference
> between these three versions of PDF -- if that difference is not
> "resolution" ?

Probably no difference at all. Have you tried it and made a comparison?

///Peter

[booklover]

On Nov 21, 6:14 pm, Peter Flynn <peter.n...@m.silmaril.ie> wrote:
>
> Probably no difference at all. Have you tried it and made a comparison?
>
> ///Peter

Yes, I did -- after I got your message.

For 2 pages of text, with no images:

+ Smallest size (for viewing PDF on the web) ... around 16 KB
+ Laser printing quality ...
around 47 KB
+ Highest quality (for hi-quality printing) ... around 145 KB
+ Highest quality + tagged PDF ... around 150
KB

Thanks, Peter

RW

[Bernd Alheit]

Can you post links to the samples?

[booklover]

> Can you post links to the samples?

Thank you for asking.

Here is a link to a zipped folder that contains the 4 PDF files that
I've just made:

http://www.box.net/shared/lr5t35e13i

From this page, click the big DOWNLOAD link, unzip and then you will
see the 4 files.

There are 4 PDF files inside only; nothing else.

RW

[Bernd Alheit]

booklover schrieb:

I can see following differences:

test-pdf-003-high.pdf - fonts are full embedded

test-pdf-002-medium.pdf - fonts embedded with subsets

test-pdf-001-smallest - fonts not embedded

[booklover]

Thank you, Bernd. I am starting to understand this a little better.

Does anyone know if it is possible to change a PDF (from one of these
three types, to another type) ?

Or must that kind of setting be made, as I did, in the source file
that is not a PDF file ?

Thanks again,

RW

On Nov 22, 4:38 pm, Bernd Alheit <be_9...@yahoo.de> wrote:
> booklover schrieb:

[Robert Heller]

Right. None of these affect the *formatting* or the dot resolution of
the text. The first is more 'portable' and is what publishers want, the
last one is great for on-line access, where minimuzing download time and
disk usage is desirable. You only *need* fonts to be embedded if you are
NOT using one of the 14 'standard' Adobe fonts.

>

--
Robert Heller -- 978-544-6933
Deepwoods Software -- Download the Model Railroad System
http://www.deepsoft.com/ -- Binaries for Linux and MS-Windows
hel...@deepsoft.com -- http://www.deepsoft.com/ModelRailroadSystem/

[booklover]

Thank you, Bernd and Robert ! ... I am getting the picture about text
in PDF.

About images in PDF:

1. When we talk about the resolution in PDF, we are talking about the
dpi of the included images? Yes / No

2. When two or more images are included in one PDF file, then the
resolution of these images must be the same dpi: if one image is 300
dpi, then another image cannot be 72 dpi ? Yes / No

3. When a PDF file has text but not searchable or editable text (let's
say: that a book page is scanned but is not OCR converted: just
scanned to PDF) -- then does this PDF file have a resolution -- just
as if the scan of the book's page had been the scan of a
photograph? ... Yes / No

Thanks again for the help !

RW

[Bernd Alheit]

booklover wrote:
> Thank you, Bernd and Robert ! ... I am getting the picture about text
> in PDF.
>
> About images in PDF:
>
> 1. When we talk about the resolution in PDF, we are talking about the
> dpi of the included images? Yes / No

Yes

> 2. When two or more images are included in one PDF file, then the
> resolution of these images must be the same dpi: if one image is 300
> dpi, then another image cannot be 72 dpi ? Yes / No

No, different images can have different resolutions

> 3. When a PDF file has text but not searchable or editable text (let's
> say: that a book page is scanned but is not OCR converted: just
> scanned to PDF) -- then does this PDF file have a resolution -- just
> as if the scan of the book's page had been the scan of a
> photograph? ... Yes / No

When scan a book page you will get one image for this page

[Robert Heller]

Unless the scanning is followed by OCR (Optical Character Recognition).

>
> > Thanks again for the help !
> >
> > RW
>

--

[booklover]

Thank you very much, again, Bernd and Robert.

And thanks once more, for any help with this last question:

How can I learn more about PDF ?

RW

[Robert Heller]

Adobe has the spec book available for download. Or you can buy a hard copy
from Amazon.com.