12 Replies Latest reply on Sep 5, 2008 7:12 AM by PeterFDuke

    Resizing photos

    Bruce Chastain
      I'm reading an older book on Premiere Elements. It stresses that all digital photos must be resized BEFORE importing in to PE.

      It has to do with the aspect ratio of the final video. Digital photos are generally 4:3 while the video frame is 3:2.

      First, since the book is old, is that still true of PE 4.0? That ALL photos must be resized to 3:2 BEFORE importing to PE?

      Does that apply to all types of projects? In other words, if I was preparing a WMV project for posting on a web site, would I also resize to 3:2, or should I leave them at 4:3 because the viewer will be a PC screen?

      Am I correct in assuming photos need to be resized ONLY if the destination is a DVD project?

      Bruce.
        • 1. Re: Resizing photos
          Ann Bens Adobe Community Professional & MVP
          No need to resize the photo's before hand unless they are of large resolution and Elements has a hard time processing them.
          Just make sure they have the right aspect ratio. You can check in the project panel/rightclick on a photo and interprete footage.
          • 2. Re: Resizing photos
            Steve Grisetti Adobe Community Professional
            No, a standard video frame is 4:3, just like your photos.

            But it is a good idea to rez your photos down to no larger than 1000x750 pixels in size before you bring them into the program, no matter what you plan to output.
            • 3. Re: Resizing photos
              Bruce Chastain Level 1
              Thanks Ann. I was wondering what that "Interpret footage" was for but hadn't yet gotten around to needing it yet. Now I know!

              And thanks Steve. What the book (Adobe Premiere Elements for Dummies) say is:

              "The frame size of NTSC video is usually 720 x 480. Do the math and you'll find this does NOT work out to be 4:3 (it's actually 3:2). However, it still APPEARS to have a 4:3 aspect ratio because NTSC pixels are slightly taller than they are wide. Too account for this difference, you have to adjust the image size of your still photos before you import them into Premiere Elements".

              "For output to NTSC video (in North America, Japan, and the Philippines), your images should be 720 x 534 pixels BEFORE you import into Premiere Elements".

              I have no idea where the 720 x 534 comes from. It's neither exactly 4:3 or 3:2. So the book makes no sense.

              Anyway, thanks for the help. I won't bother to preadjust my photos except to downsize them as you said.

              Bruce.
              • 4. Re: Resizing photos
                Steve Grisetti Adobe Community Professional
                Boy, is that confusing, Bruce! You should have bought my book instead! ;)

                Actually, what the author is saying is true. Video frames are 720x480 pixels. But, in video, the pixels are only 90% as wide as they are tall (NTSC) for technical reasons dating back to the development of television.

                So, if you do THAT math (multiply 720 x 90%), you'll see that 720x480 video pixels is equivalent to 640x480 square pixels -- and THAT is a 4:3 aspect ratio. (That's why, when you output a WMV file from your video, it comes out as 320x240, half of each dimension of 640x480.)

                Does that make sense?
                • 5. Re: Resizing photos
                  PeterFDuke Level 1
                  Steve and Chuck's "In a Snap" book is unfortunately in error in a number of places on page 98. Let's see if I can get it right :)

                  Standard NTSC's 720x480 is equivalent to 640x480 square pixels
                  Standard PAL's 720x576 is equivalent to 768x576 square pixels
                  Widescreen NTSC's 720x480 is equivalent to 864x480 square pixels
                  Widescreen PAL's 720x576 is equivalent to 1024x576 square pixels

                  Note that standard and widescreen videos have the same pixel dimensions, but the pixels are non-square in both cases and have different pixel aspect ratios.

                  If you have have photos with larger pixel dimensions than the equivalents above, in theory you won't lose any quality, but practical resizing algorithms may differ slightly from the ideal. Photos with lower pixel dimensions will show some fuzzyiness. Also note that the DPI (dots per inch) of a photo is irrelevent in video work - it only affects printing size or display size on a computer screen.

                  P.S. The value 864x480 for widescreen NTSC is strange because I would have expected 853x480 which is 16:9 ratio. I determined 864x480 by trial and error in PE2, so it may no longer be true.
                  • 6. Re: Resizing photos
                    Ann Bens Adobe Community Professional & MVP
                    If you do resize for video you best set it at 72 dpi.
                    • 7. Re: Resizing photos
                      PeterFDuke Level 1
                      DPI is irrelevant in video work.
                      • 8. Re: Resizing photos
                        Bruce Chastain Level 1
                        Ok, as usual, simple questions have a habit of getting more complicated than I'd hoped. :-)

                        Steve, I do understand what you said and it makes sense. While you didn't mention the book's 534 number, it just so happens that 90% of 534 is 480 (480.6) so I assume that's not just a coincidence. Luckily for me, PE does the adjustment for me, so I won't be needing a calculator to do a video project. :-)

                        BTW, I looked up your book on Amazon and the table of contents looks very interesting and covers topics I want to understand better, so I ordered a copy. :-)

                        Peter, I'm confused by one thing you said. You said:

                        Standard NTSC's 720x480 is equivalent to 640x480 square pixels
                        Widescreen NTSC's 720x480 is equivalent to 864x480 square pixels

                        I'm having trouble getting my head wrapped around that. I've always assumed that widescreen has more horizontal resolution than standard, as your pixel count shows. But if so, then why do you refer to both standard and widescreen as 720x480? Does widescreen have more horizontal resolution than standard or doesn't it?

                        Bruce.
                        • 9. Re: Resizing photos
                          Steve Grisetti Adobe Community Professional
                          Good man, Bruce!

                          Bring it by the house and I'll be glad to autograph it for you! ;)
                          • 10. Re: Resizing photos
                            PeterFDuke Level 1
                            The encoded video pixels are the same for standard and widescreen, but of course in digital TVs there are more pixels in widescreen. The pixel shape changes, that is all. Widescreen video has wide pixels.

                            Widescreen stretches the pixels so a purist might argue that widescreen looks fuzzy in the horizontal direction, but I have never heard or seen such a comment.
                            • 11. Re: Resizing photos
                              Ann Bens Adobe Community Professional & MVP
                              > DPI is irrelevant in video work.

                              Sorry: pii
                              72 ppi is what Photoshop/Premiere uses to import/export grafics.
                              • 12. Re: Resizing photos
                                PeterFDuke Level 1
                                I took an image 768x576 pixels at 72 dpi and resampled it in my image editor to be 768x576 at 300 dpi. When viewing in the print preview of the editor, the 72 dpi version was too wide for the paper, whereas the 300 dpi version was quite tiny. So changing the dpi changes the size the image is printed on paper. The two versions had exactly the same file sizes. When imported into PE with "scale to frame size" off, the two images appeared identical. Since I use PAL, 768x576 just fills the screen. So the dpi is irrelevant during import into PE.

                                So far as export is concerned, the dpi field in the image header has to be set to something, and it is set to 72 dpi as you say. This is quite arbitrary, but no doubt 72 dpi is used because it is very common. My still camera also uses 72 dpi. This probably dates back to those old dot matrix ribbon printers which preceded inkjet printers.