5 Replies Latest reply on Apr 29, 2016 11:54 AM by trshaner

    Exporting in Lightroom and Resolution Size

    Nigel1985

      Hi All,

       

      I a recent Bridge/Photoshop convert to Lightroom/Photoshop. I want to start using Lightroom to resize my images instead of Photoshop. But, if I really crop an image and export at 1440x960 ( at 150 PPI), I run the risk of resizing up the image, which I don't want. I understand there is the "Don't Resize" button in Lightroom.

       

      My question: What gets ignored if Lightroom needs to increase the image size based on my inputs and the 'Don't Resize' box is checked?

       

      Here's my old workflow in Photoshop (client wants these dimensions)

      RAW: 5184x3456 at 300PPI

      Resize to 150 PPI (which changes dimensions to 2592x1728)

      Resize to 1440x960 at 150 PPI

      Save to JPG sRGB

       

      But, sometimes if I really crop an image I can't get 1440x960 at 150 PPI and have to keep the PPI at 300.

       

      SO...

       

      If I export a really cropped image in Lightroom at 1440x960 at 150 PPI (dont not resize checked) and it can't meet the dimensions at that resolution what get's ignored?

        • 1. Re: Exporting in Lightroom and Resolution Size
          dj_paige Level 9

          The whole idea of using PPI on digital photos is causing your confusion.

           

          Digital photos are measured in pixels. They are not measured in inches, nor does PPI have any meaning for digital images (it does have meaning when you print and the photo then becomes a physical photo, not a digital photo).

           

          So when you say

          But, sometimes if I really crop an image I can't get 1440x960 at 150 PPI and have to keep the PPI at 300.

          Please note: an image that is 1440x960 is the exact same image with the exact same pixels at 300 PPI versus 150 PPI. There is exactly no difference.

           

          Here's another example of how using PPI misleads you

          RAW: 5184x3456 at 300PPI

          Resize to 150 PPI (which changes dimensions to 2592x1728)

          Simply not true. if the photo is 5184x3456, changing the PPI does not change the number of pixels.

           

          Why? Because PPI has no meaning for digital photos.

          • 2. Re: Exporting in Lightroom and Resolution Size
            99jon Adobe Community Professional & MVP

            Simply export from the original raw file and choose 1440 long edge & 150 ppi

            • 3. Re: Exporting in Lightroom and Resolution Size
              Nigel1985 Level 1

              Thanks for the quick reply. I understand the digital v physical implications of DPI and that (1440px is 1440px regardless of 150 or 300 PPI).

               

              I am confused when you say it doesn't change the dimensions. When I alter the Resolution field (pixels/inch) under Image Size field in Photoshop, it changes the W and H of my image, as described above. I simply cannot change my file from 300 > 150 PPI and keep the original 5184x3456 dimensions.

               

              So, what happens when I resize my 300 PPI image at 5184x3456 in light room? It asks for both W/H and resolution. So if I enter 1440x960 and 150, wouldn't the change in PPI from 300 to 150 reduce first the overall dimensions (as it does in Photoshop) and then reduce further to meet my 1440x960 dimensions?

               

              If that is true, what will be ignored (either PPI or dimensions) if the Don't Enlarge is checked and it cannot meet both the 150 and W/H?

              • 4. Re: Exporting in Lightroom and Resolution Size
                dj_paige Level 9

                If you have specified the export to be a specific number of pixels (width and height) and change the PPI, the number of pixels (width and height) does not change, the exported photo has the same number of pixels regardless of the PPI.

                 

                It's only if you are exporting and the units in the Image Sizing dialog box are set to inches or centimeters when PPI makes a difference.

                 

                So which are you doing?

                • 5. Re: Exporting in Lightroom and Resolution Size
                  trshaner Adobe Community Professional & MVP

                  Nigel1985 wrote:

                   

                  Here's my old workflow in Photoshop (client wants these dimensions)

                  RAW: 5184x3456 at 300PPI

                  Resize to 150 PPI (which changes dimensions to 2592x1728)

                  Resize to 1440x960 at 150 PPI

                  Save to JPG sRGB

                  Client wants what dimensions? If this is for layout usage or prints a specific dpi AND size in inches must be specified. I suggest asking the client to provide both of those numbers.

                   

                  In your above example here's what you have:

                   

                  2592x1728 @150 ppi = 17.28 in. x 11.52 in. So what is the client trying to do? Makes no sense!

                   

                  If you specifically want an image that is 1440x960 @ 150 ppi then use the suggestion provided by .

                   

                  "Simply export from the original raw file and choose 1440 long edge & 150 ppi."

                   

                  Concerning cropping that causes the image to be enlarged you'll know immediately if the Cropped Dimensions as shown in the LR Library module are less than 1440x960. Use the 'I' key to cycle the Loupe view Info selection if you can't see the Cropped Dimensions.