When the PDF options panel opens, use the drop-down at the top and choose High Quality Print. That should do it, but if you are still in trouble, go through the other tabs in the pdf options panel, and choose 300dpi in Compression.
Thanks for your comment Trevor. Unfortunately I've already tried every options and still the dimensions have been reduced. Any other idea where i fail?
You need to look through everything right from the begiining then.
What units are you using? If inches you have a file
4 inches x 2 inches @ 300 dpi (Is that right and OK?)
What does the document consist of before you save to pdf? Are there any bit map layers (Photographs?) and what were their pixel sizes before importing them if there?
Upload a screen grab showing image and layers.
Then, just to be save, upload a screen grab of the Print preview panel with the printer set to 10x8 or A4 or whatever you use.
If all that checks out, then we'll look again at the PDF settings.
Can you also tell us what version of Photoshop you are using?
Hi. I replicated an image that has the same image setting (as your screenshots) and saved it as Photoshop PDF. I then viewed the image in Adobe Bridge, Preview, Illustrator and Acrobat Reader.
I got the same 'magic number' of 288x144 for the first 3 applications. I also found that the units used is actually 288x144 points and not pixels.
WIth 1 inch = 72 points, 288x144 points translates to 4x2 inch. So your image didn't strunk or downsize. It just describes the physical size of the image in points and not in inches.
Acrobat Reader (inder properties) indicated that the file is still 4x2 inch.
If I create a lower resolution image (from 300 to 72ppi) with the same 4inchx 2 inch and save as PDF with the same settings, the same apps above still indicates 288x144 points. Its just that the PDF file size is smaller than the one that is created from the 300ppi PSD file.
The physical size of the image does not changed when you save as Photoshop PDF and the resolution should remain intact as long as you do not downsample when you save as PDF. Hope this helps.
Thanks for your help, but honestly still doesn't get it:) Creating 72ppi document is not an option as i want to use 300ppi images in it. What i dont understand is that if i save the same document in Png instead of pdf it just remains with the right size 1200x600 300ppi, but with pdf it doesn't. Why is it such a problem?
When you saved and reopen Photoshop PDF in Photoshop, Did the resolution in Image Size changed to 72ppi?
Nope, it's normal in PS with 300ppi and the right dimensions. So there should be some very trivial answer for it, probably it's so simple that we missed it
Its still 300 ppi because physical size and resolution does not change when converted to PDF. You probaby have noticed that the qualify of the image have not degraded as it should have if it actually changed from 300 to 72 ppi.
If your concern is not for your images's qualitty to be degraded when converting PDF, the important thing to to set the Adobe PDF Preset as [Hige Qualify Print] (third screen shot from the top in post #4 that you posted) it should be fine. Cheers!