12 Replies Latest reply: Oct 28, 2009 9:34 AM by D Fosse-QDEaQ1 RSS

    Resizing DPI

    sfjedi Community Member

      Here's the scenario:

       

      I have this image that's 2162x3092 @ 72 dpi.

       

      I'm going to be airbrushing the white parts of this image and I want the absolute highest quality. How should I go about doing this?

       

      To help you answer this question, these are the ideas flowing through my mind:

       

      1. Maybe I can downsize it to like 1000x1430 and compensate for this by knocking up the dpi setting at the same time? No idea what dpi setting to use though.
      2. Maybe I can knock up the dpi to 300, but then what resolution would I put it at? Should it change at all? Is there a special formula to use here?

       

      Now, I'm assuming that the answer will probably be that I *should* knock the dpi setting up to 300 for airbrushing. That way at least the airbrushed parts will print out nicely (everything else will be less quality), but there's no reason to resize the image whatsoever, right?

        • 1. Re: Resizing DPI
          Q Photo Community Member

          In image size, replace 72 PPI with 300 PPI.  Be sure that RESAMPLE in NOT checked.  You will end up with an image that is slightly over 7" by 10" at 300 PPI.  DPI (Dots Per Inch) is a printer setting and has nothing to do with image size, which is stated in Pixels Per Inch.

          Make a copy layer and do your work on it, not the original background layer.

           

           

          • 2. Re: Resizing DPI
            Maneet Puri Community Member

            Hi,

             

            Yes, you are on the right track. Change the resolution to 300 dpi.

             

            Cheers,

             

            Maneet Puri,

            LeXolution IT Services

            • 3. Re: Resizing DPI
              D Fosse-QDEaQ1 Community Member

              Maneet Puri wrote:

               

              Hi,

               

              Yes, you are on the right track. Change the resolution to 300 dpi.

              This is very misleading when not qualified. Q has it right, but just to fill in:

               

              Image quality is determined by the pixel dimensions, nothing else.

               

              Resolution in ppi (not dpi) is just metadata to tell the printer what physical dimensions to print at. It helps you determine how many pixels you need for a given reproduction size. For commercial reproduction in books, magazines and so on the requirement is usually 300 ppi, so that tells you how big it can be reproduced with the pixels you have.

              • 4. Re: Resizing DPI
                sfjedi Community Member

                OK, let me clarify a little bit here.

                 

                Think of it as a coloring book, because that's exactly what it is. The black lines (drawing) is on its own layer on top of everything with a multiply filter so only the black portions show through. This image is at 72 ppi.

                 

                Now, the part I'm going to airbrush sits directly beneath this layer. If I increase the image resolution to 300 ppi, this layer will be 300 ppi because I'm painting fresh on it, right?

                 

                But then when I print it, won't the top layer look all pixelated, potentially? And the layer beneath it will look more clean? The layers won't be consistent in print, but it will be on the screen?

                 

                If this were the case, I might as well just keep it at 72 ppi and paint on that, no?

                 

                Maybe I'm missing something here?

                • 5. Re: Resizing DPI
                  shunithD Community Member

                  Jed,

                   

                  All layers will be at the same ppi as a simple check in Image Size will tell you. You can't have different layers set at different ppi in the same file.

                   

                  Please understand the following:

                   

                  1/ The size of the image is determined by the pixels (width) x pixels (height). A file of 900 x 900 pixels at 72 ppi is the same size as a file of 900 x 900 pixels at 300 or 600 or even 1000 ppi per inch.

                   

                  2/ The 72 ppi and 300 ppi is as follows:

                  a. At 72 ppi, the above file will print at 12.5 inches x 12.5 inches (larger print area, poorer quality)

                  b. At 300 ppi the file will print at 3 inches x 3 inches (smaller print area, better quality)

                   

                  But the file is the same size... Only information to the printer is different. So for best output quality, do what was suggested. Keep the pixels count intact. Just increase the ppi to 300 with the Resample option unchecked.

                  • 6. Re: Resizing DPI
                    sfjedi Community Member

                    shunithD wrote:

                     

                    1/ The size of the image is determined by the pixels (width) x pixels (height). A file of 900 x 900 pixels at 72 ppi is the same size as a file of 900 x 900 pixels at 300 or 600 or even 1000 ppi per inch.

                     

                    2/ The 72 ppi and 300 ppi is as follows:

                    a. At 72 ppi, the above file will print at 12.5 inches x 12.5 inches (larger print area, poorer quality)

                    b. At 300 ppi the file will print at 3 inches x 3 inches (smaller print area, better quality)

                     

                    Ding!!! Light bulb finally turned on! I've dealt with this confusion for YEARS and YEARS and I understood it to an extent, but only NOW do I finally understand it 100%!

                     

                    I even read all about it before, but I think the location of this setting has always been the source of my confusion. It seems like it belongs in the print settings to me.

                     

                    shunithD wrote:

                     

                    But the file is the same size... Only information to the printer is different. So for best output quality, do what was suggested. Keep the pixels count intact. Just increase the ppi to 300 with the Resample option unchecked.

                     

                    So, if I understand correctly, this change in the ppi really doesn't matter if I do it before or after I do my airbrushing, does it?

                    • 7. Re: Resizing DPI
                      D Fosse-QDEaQ1 Community Member

                      As long as you don't resample, no, it doesn't matter. It doesn't affect the file itself.

                       

                      And yes, that could have been in the Print dialog. The problem is that if  "resample" is checked, the whole thing turns into a completely different (and much more dangerous) animal. Another problem is that it's also used when placing smart objects.

                       

                      If it was up to me, resample should have been taken out of the image size dialog and put in its own file size dialog. That innocent-looking little checkbox is a stick of dynamite concealed as candy.

                       

                      BTW shunithD's post is a splendid explanation.

                      • 8. Re: Resizing DPI
                        sfjedi Community Member

                        D Fosse wrote:

                         

                        As long as you don't resample, no, it doesn't matter. It doesn't affect the file itself.

                         

                        Thank you!

                         

                        D Fosse wrote:

                         

                        BTW shunithD's post is a splendid explanation.

                         

                        I 100% agree and apologize to him that I am new to these "mark as helpful" and "correct answer" buttons and it seems that it's too late for me to go back and mark his as the correct answer, or I would have swapped yours for helpful as his as the answer.

                         

                        Sorry, shunithD!

                        • 9. Re: Resizing DPI
                          D Fosse-QDEaQ1 Community Member

                          That's OK. I owe you one, shunith...

                           

                          (And on second thought I suppose it couldn't be in the Print dialog for many other reasons, but...hypothetically...it could).

                          • 10. Re: Resizing DPI
                            shunithD Community Member

                            No problem Jed... As long as you've got the concept right!!

                            • 11. Re: Resizing DPI
                              shunithD Community Member

                              D Fosse wrote:

                               

                              That's OK. I owe you one, shunith...

                              I'll settle for a beer one of these days Even a virtual beer is better than these ive A$$ points!

                              • 12. Re: Resizing DPI
                                D Fosse-QDEaQ1 Community Member

                                You got it. I assumed you wouldn't mind