8 Replies Latest reply on Feb 24, 2017 4:14 AM by mibcd

    Image DPI

    mibcd Level 1

      Hi,

       

      I am designing a 12 by 3 billboard. My printer said it needs image res at 300 ďpi.

       

      My images are more than 2000 px w h. But at 72 ďpi. How to I change that?

        • 2. Re: Image DPI
          mibcd Level 1

          Its in meter. I am designing 120cm by 30cm.

          • 3. Re: Image DPI
            gener7 Adobe Community Professional & MVP

            120 x 30 cm at 300 ppi (pixels per inch) gives you 14173 x 3543 pixels.

             

            That seems 7 x the 2000 pixels needed.  You simply can't blow up pixel based artwork that artwork up that far. You would have to create it at those dimensions.

             

            I don't have experience in poster printing, but if you are in Europe, this may help.

             

            The designer's guide to printing a poster | Creative Bloq

             

            Then talk to your printer again, especially if your images are too small.

            Screen Shot 2017-02-23 at 10.08.36 PM.png

            • 4. Re: Image DPI
              davescm Adobe Community Professional

              There are two things here.

              First, the PPI that your printer has requested. That is easy - you use Image Size - with resample to give that resolution. That way you can send the printer the file he has requested.

               

              The second, which does not affect any vector parts of the image (i.e. text or shapes) but does affect the pixel image,  is how many pixels does your image need to be acceptable for viewing. Unless your billboard will be viewed from a few cm away with a magnifying glass then you don't need to start with 300ppi. The ppi needed depends on viewing distance. Our eyes can only resolve so much detail.
              As a rule of thumb - the viewing distance is about 1.5 x the diagonal so in your case - about 10-12 metres (approx. 480 inches)

               

              There is a formula in the link below for working out the ppi required at a given viewing distance. In your case it suggests around 15 ppi.  So your 12 metre length needs to be around 7000 pixels - anything else is a waste, because you won't see it at the normal viewing distance.

              What print resolution works for what viewing distance?

               

               

              In short get your image looking good at 100% zoom and 7000 x  1750 pixels. Then do a final increase in size to the dimensions required by your printer.

               

              Dave

              • 5. Re: Image DPI
                D Fosse Adobe Community Professional & MVP

                All of which can be quite simply summed up:

                 

                Any high-resolution camera image will work, at any physical print size. If it works as a magazine spread, it'll also work as a huge billboard. The file doesn't have to be upsampled and enlarged because of the bigger print size.

                 

                The bigger it is, the further away it will be seen from, and the lower the ppi needs to be.

                 

                This is because optical, perceived resolution is really about degrees of arc in your total field of vision, not absolute pixels. You will always tend to stand at a distance where you can comfortably take the whole image in - so the perceived size on your retina will be the same.

                 

                And just so it's clear - print size, ppi, is metadata, arbitrarily assigned. It is not a native property of the file, which is just pixels.

                • 6. Re: Image DPI
                  mibcd Level 1

                  My printer said 15 ppi output. Is that the final work combined with raster, text and vectors?

                  How do i input or ensure these values from Indesign or Illustrator?

                   

                  P.s im designing at 10 percent

                  • 7. Re: Image DPI
                    mibcd Level 1

                    My printer said 15 ppi output. Is that the final work combined with raster, text and vectors?

                    How do i input or ensure these values from Indesign or Illustrator?

                     

                    P.s im designing at 10 percent

                    • 8. Re: Image DPI
                      mibcd Level 1

                      ppi for what? the photo for the billboard or the whole artwork consisting of the text and vectors, like the final output?

                       

                      Here's my workflow:

                       

                      1. I created a 120cm by 30cm artboard in Illustrator. (Designing at 10%)

                      2. Not so sure..time to place my image onto Illustrator artboard..So right now, do i fire up Photoshop and blow up my image size?

                      3. Artwork done (after part 2). I export it as PDF with all bleed and marks. And I'm done.

                      Say my image is like I said above 2000px or even better 5000px, what do i do before placing in Illustrator?

                      So when ppl say 15ppi, do they mean I open the FINAL artwork in Photoshop and tweak the resolution?

                       

                       

                      PLEASE help me. I'm asking a lot. I really need good advice and help. Thanks.