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Scribus => PDF Generation => Topic started by: sebo on June 12, 2013, 07:16:36 pm

Title: PDF: 300 dpi wanted, only 72 dpi
Post by: sebo on June 12, 2013, 07:16:36 pm
Hey,

I searched the forum and Google for my problem but couldn't find a solution yet.

I am exporting a document as PDF. When I did this before (same computer, same scribus version), I got PDFs with 300 dpi.
However, I can't manage to this time, it always turns out as "Resolution: 72 x 72 dpi" (as ImageMagick's identify says). All pictures in the document have dpis > 1000.

Any suggestions?

Thanks!
Sebastian
Title: Re: PDF: 300 dpi wanted, only 72 dpi
Post by: GarryP on June 12, 2013, 09:54:19 pm
If the images in the PDF are at a resolution below that which you expected you can try checking the "Save as PDF..." Compression and Maximum Image Resolution settings.
You might have adjusted something by accident.
Title: Re: PDF: 300 dpi wanted, only 72 dpi
Post by: Boe on March 29, 2014, 02:29:53 pm
I have the same problem. I select File > Export > Save as PDF. All I have on the page is some text generated in Scribus and one jpg image which was 600 dpi when I got the image. When I go to export to PDF it creates a 72 dpi PDF. I want 300 dpi or more. I tried the suggested settings with compression such as 'None' ,  'Lossless - ZIP', etc. I also tried 'Embed as PDF & EPS files'. Every setting change I make still creates a 72 dpi PDF.
Title: Re: PDF: 300 dpi wanted, only 72 dpi
Post by: utnik on March 29, 2014, 08:19:33 pm
hi boe

what's the entry of the 'maximum image resolution' box in 'save as pdf'?
utnik
Title: Re: PDF: 300 dpi wanted, only 72 dpi
Post by: Boe on March 30, 2014, 04:58:45 am
Hi utnik,

'Maximum image resolution' is set at 300 dpi. I've tried it both ticked and unticked. That was the first thing I checked when I realised the dpi was defaulting to 72.
Title: Re: PDF: 300 dpi wanted, only 72 dpi
Post by: utnik on March 30, 2014, 08:54:34 am
could you upload a test file (.sla with image and .pdf) somewhere?

utnik
Title: Re: PDF: 300 dpi wanted, only 72 dpi
Post by: Boe on March 30, 2014, 09:28:10 am
I have been uploading the files to a site where they have an image wizard that tells you how many dpi the image is (its a tshirt manufacturer, so they provide an image wizard to check your image is the right size on the tshirt). According to every upload I do on this site, every change I make has resulted in a 72 dpi image.
Title: Re: PDF: 300 dpi wanted, only 72 dpi
Post by: utnik on March 30, 2014, 09:37:52 am
as long as you keep your files secret i'm not able to help!

a dummy file with an image would do, as long as it produces the same low resolution problem.

utnik
Title: Re: PDF: 300 dpi wanted, only 72 dpi
Post by: Boe on March 30, 2014, 01:29:50 pm
Sorry, you are talking with a complete beginner here, and I guess I did not take in the whole of what you said. I read "upload a test file" as yes, I have uploaded my files, and "somewhere" being, yes I have uploaded them to the tshirt manufacturer's site. I did not realise you wanted to scrutinize the files. What do you mean by "somewhere"?

BTW, I forgot to mention that when I export the files as images, whether as PNG or TIF, it creates the right resolution, i.e. I get a 300 dpi image. Does that help?
Title: Re: PDF: 300 dpi wanted, only 72 dpi
Post by: utnik on March 30, 2014, 01:55:01 pm
hi boe

What do you mean by "somewhere"?

if you have a dropbox (https://db.tt/8VAtgrb) account, it could be there – but almost every file hoster would do (like rapidShare (https://rapidshare.com/security/products), file-upload.net (http://www.file-upload.net/)…)
if putting the link into this thread is too public for you, send a pm.

Quote
…when I export the files as images … it creates the right resolution … Does that help?

at least it tells me that the image resolution is ok.

utnik
Title: Re: PDF: 300 dpi wanted, only 72 dpi
Post by: Boe on March 30, 2014, 02:58:26 pm
Thank, utnik. PM sent.  :)
Title: Re: PDF: 300 dpi wanted, only 72 dpi
Post by: utnik on March 30, 2014, 03:57:38 pm
hi boe

i need the same image files you used.

your .sla file is searching for a fille called:
i found the files:
try the function: 'file' – 'collect for output'
btw. it's not scribus, its the  definitions por portable network graphics (.png) which doesn't support cmyk…

utnik


edit: i have extracted the image of the bird from your .pdf file. it is a 300ppi image in rgb! – where is this resolution problem now?
Title: Re: PDF: 300 dpi wanted, only 72 dpi
Post by: Boe on April 07, 2014, 03:42:59 pm
Do you mean ppi or dpi? I need 300 dpi. If you upload the PDF to this page, what is the dpi?
https://printaura.com/image-wizard/
Title: Re: PDF: 300 dpi wanted, only 72 dpi
Post by: Nermander on April 07, 2014, 03:48:13 pm
Well, the DPI can never be lower than the PPI.

During printing, each Pixel (as in PPI) is made up of one or more ink Dots (as in DPI).
Title: Re: PDF: 300 dpi wanted, only 72 dpi
Post by: Boe on April 07, 2014, 04:00:04 pm
Nermander, so 300 ppi can be made from a file smaller than 300 dpi? eg, 300 ppi can be a 72 dpi file?
Title: Re: PDF: 300 dpi wanted, only 72 dpi
Post by: utnik on April 07, 2014, 04:10:37 pm
hi boe

the proplem is: you need 300ppi, but you don't know the difference – and lots of people (and some graphic programs) don't differentiate between the two…

utnik
Title: Re: PDF: 300 dpi wanted, only 72 dpi
Post by: Nermander on April 07, 2014, 04:26:27 pm
Boe, you are saying the opposite...

PPI is pixels per inch. This is what most people really mean when they say DPI.

A digital image normally only have pixels. It does not "have" a DPI or PPI. It might have a DPI number inside, but that number is nearly useless.
(Note: I just read the JPEG is the only image format containing a field for DPI!)

If you have an image that is 2000x2000 pixels and print it at a size of 2x2 inches you print it at 1000 PPI. If you print the very same image at a size of 5x5 pixels you print it at 400 PPI. The DPI value inside the image might still just say 72 DPI.


Now, when printing a pixel the printer needs to be able to give the pixel a certain color. However the printer only contains a finite number of inks, each with it's own color. To be able to give the pixel the desired color the printer must print one pixel using several dots. This becomes the DPI value.

For example a 1200 DPI inkjet printer will usually only be able to print 300 PPI, while using 4x4 ink dots for each pixel.

Look at the illustration on this page.

http://mydigitalcamera.us/ppi-vs-dpi-resolution-what%E2%80%99s-the-diff/

This means it is virtually impossible to print a 300 PPI image with less then 300 DPI (some types of printer can print a pixel using just one dot where they mix different amounts of the inks).


Found another page with some better illustrations and more info
http://99designs.com/designer-blog/2013/02/26/ppi-vs-dpi-whats-the-difference/
Title: Re: PDF: 300 dpi wanted, only 72 dpi
Post by: Boe on April 08, 2014, 06:26:20 am
Hi Utnik and Nermander,

I am just trying to conform to the tshirt printer's specification of 300 DPI.  So far all the tshirt printers I have checked out ask for the artwork in DPI. Here is an example of the specs from theprintbar.com:

"Our printers print at 600 x 600dpi or 1200 by 1440dpi (printers use only dpi) with large drops of ink."

Note "printers use only dpi".

At the end of the day Scribus has a DPI output feature but every change I make to any settings that affect the DPI still result in the default viewing resolution of 72 DPI.

You are teaching me a lot about ppi (which I appreciate  :D) but this doesn't resolve my problem with Scribus' DPI output, unless something you are saying is going over my head.
Title: Re: PDF: 300 dpi wanted, only 72 dpi
Post by: Nermander on April 08, 2014, 08:58:40 am
Read the pages I have linked to!

Quote
Today, “dpi” can also be used to mean printer droplets per inch (for inkjet printers) or maybe pixels
per inch (for photo files and full-color devices just like displays, photographic output devices,
and also dye sublimation printers). Quite simply, it doesn’t make reference to a single standard unit of
measure. That is the seriously confusing situation to get a lot of people.

Quote
Now, that being said, people say “DPI” when they really mean “PPI” all the time — so much so that it has become an established convention that you have to put up with (Apple, Microsoft and Adobe have all been guilty of this improper usage). The important thing is to be able to know whether someone is referring to actual DPI or really means PPI.

So, 9 times out of 10 (or even more), when people say DPI they really mean PPI.
Title: Re: PDF: 300 dpi wanted, only 72 dpi
Post by: utnik on April 08, 2014, 09:34:26 am
hi boe

the whole dpi versus ppi thing was initiated when you asked me if i mean ppi or dpi! (we knew that you're talking about ppi before, but we didn't mention it…)

for your initial problem, i told you all i could find in the files you provided.
yesterday you asked:
Quote
Still waiting for help on this one. Does anyone else have the answer? I'm desperate now.


so i think you're searching for someone who is willing to help without your cooperation…


utnik