10 Replies Latest reply on Oct 14, 2009 10:27 AM by Kathlene Ruhan

    Images size above 120%

    Tomchook Level 1

      I'm using InDesign CS3. How large can I resize my images without affecting the quality? When I used to work with Quark I could resize up to 120%, and if I wanted to increase further, I would have to do it in Photoshop. Is it possible to increase in InDesign more than 120% without using photoshop?


      I know it's mostly a matter of taste, but I would really appreciate your opinion!

      By the way, some of my images are 72dpi and only few are 300dpi. I'm creating a document for press (newspaper)


      Thank you!



        • 1. Re: Images size above 120%
          [Jongware] Most Valuable Participant

          Repeat after me:

          The scale does not matter, nor does the initial resolution.


          The scale does not matter, nor does the initial resolution.


          The scale does not matter, nor does the initial resolution.


          ... until you believe it! The only thing that matters is the effective resolution -- the product of both initial image resolution and scale! This ought to be high enough for your printing process -- 300 dpi is for rather good printing (books), 450 dpi and higher for glossy magazines. For newspapers, which I guess will be printed around 120 lpi, 240 dpi is enough.


          To check the effective resolution, all you need to do is select an image and look in the Info panel.



          By the way: If you need an image with an higher resolution than provided, get a new one. Scaling an image up is useless, as you are 'inventing' new image data (esp. when "upsampling" an image from 72 dpi to printing rez).

          • 2. Re: Images size above 120%
            Petteri_Paananen Level 4

            In InDesign scaling % is irrelevant, because you have different ppi values used with your images. Instead of that, you could monitor your image´s effective ppi. You will find it from Info panel (Window>Info) Every time you have image selected, you will see actual ppi and effective ppi of that image. Actual ppi is not important, it´s just a value that has been given there in Photoshop or even Digital Camera... Effective ppi measures your image´s current resolution after scalings. If it´s more than 240ppi, I would say you´re safe.... (with normal coated printjobs)

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            • 3. Re: Images size above 120%
              Printer_Rick Level 4

              A good goal is for effective PPI and output PPI to be the same thing.


              To explain better, when you make a PDF you have an option to downsample all images. A print standard value is 300 PPI, which should well work for you. So if you have a 300 PPI placed at 100%, the effective = output.


              Whenever effective = output, when you view at actual pixels in Photoshop, you get to see the most important resolution of all. Optical resolution. Unfortunately this has no number. It's the clarity if the image.


              300 PPI placed at 100% gets you there, and I believe there is a script which achieves this (I will try to locate it's at the InDesign secrets website). But even without a script there's a simple formula. Output PPI X Scale % = Photoshop PPI. For example 300 X 25% = 75 PPI. Bicubic sharpen downsample in Photoshop (for reduction) to 75 PPI (make a copy of the original first). Now look at the image at 100% in Photoshop to see an approximation of print clarity.


              This is important because you never can be too sure about the history of an image, or how it was made. I have seen images with too low a PPI that look pretty decent. I have also seen images with too high a PPI that look horrible, probably because some bozo upsampled to "help" the poor quality image. (If only it worked like it does in the movies)


              Oftentimes I get the question "are the images low resolution"? The true answer is no, because on the press sheet the numerical resolution is the same for everything (it all comes from the same plates). What matters is what the images look like, and you can't assign a number to appearance.


              To answer your original question - if you have a 300 PPI in Photoshop and it looks good at actual pixels, keep the scaling in a window of tolerance, maybe between 75% and 125%. This window yields 400 PPI - 240 PPI (effective). Just remember the more you scale, the more removed you are from the optical resolution you see at actual pixels in Photoshop.

              • 4. Re: Images size above 120%
                Printer_Rick Level 4



                The script is called "Resample Images to 100%", it may be useful. Whenever an image is placed at 100%, actual and effective PPI are both the same, so there's a lot less confusion.

                • 5. Re: Images size above 120%
                  RorohikoKris-u5pUJw Level 2

                  This might be of interest: our FrameReporter plug-in allows you to quickly check the effective PPI of multiple images - instead of checking them one by one via the Info palette:


                  Check it out at:  http://www.rorohiko.com/framereporter

                  • 6. Re: Images size above 120%
                    Mike Ornellas Level 3
                    The scale does not matter, nor does the initial resolution.


                    This is completely wrong in some situations.  Though effective resolution is true, this statement is inaccurate when you are dealing with Photoshop clipping paths and images placed at extreme increase or decrease percentages.


                    For example,


                    the receiving RIP will either blow up the files or create very rough edges from clipping paths and or vector masks.




                    So to have a blanket statement would be misleading.  There is more then resolution in play here.

                    • 7. Re: Images size above 120%
                      RorohikoKris-u5pUJw Level 2

                      P.S. The podcast mentioned earlier by Rick also has interesting info in this respect - I remember listening to it, and David mentioned something about applying unsharp mask. If I remember correctly, depending on the material at hand, you often want this sequence:


                      a) scale image in Photoshop to desired resolution

                      b) apply unsharp mask in Photoshop

                      c) place image at about 100% in InDesign


                      If you rely on InDesign scaling, the sequence of operations is often reversed:


                      a) apply unsharp mask in Photoshop

                      b) place image in InDesign

                      b) scale in InDesign


                      which can have negative side effects.

                      • 8. Re: Images size above 120%
                        [Jongware] Most Valuable Participant

                        Mike, can you show a concrete example of what you mean? The "flatness" of an exported path is resolution-dependent, but it's expressed in pixels. E.g., a flatness of 0.5 indicates half a pixel, regardless of what the resolution of the image is.


                        I still think my rule-of-thumb is always true, for a large value of "always".

                        • 9. Re: Images size above 120%
                          Mike Ornellas Level 3

                          Yes in general your rule of thumb is correct, but sometimes you can't actually see the clipping path issues in Acrobat and they can only be seen on a hard copy proof. RIPS such as Rampage or Creo Scitex that has a CT and LW workflow will for sure distroy the files when paths are pushed beyond reasonable scaling sizes.

                          • 10. Re: Images size above 120%
                            Kathlene Ruhan Level 3

                            I am afraid resolution does matter -


                            If you have a a resolution of 300ppi and you scale it to 300%, well, your image resolution will be 100ppi. Your intended resolution is 300 and you can output/export and or print that but really, applications other than your image application do not have the ability to interpolate the surrounding pixels and create an new pixels based on the information in that image file and will chop and dice your resolution to make it 300ppi on output, but it is not actually a pixel of true information. To change a bunch of improperly res'd files in Indesign, you can trick it by making as PS blank file and placing it with transparency effects, but there again, the pixel interpolation process is not of the highest standards. Depending on your standards, you can do it any way you want, although 72ppi res files are not print quality images. Your halftone at 72ppi would be around 36dpi.

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