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kentmcpherson
kentmcpherson
Inspiring
October 13, 2020
Question

Export Image Sizing Question

  • October 13, 2020
  • 5 replies
  • 4224 views

In the Export dialog for LR Classic 9.4, one of the sections is Image Sizing. In that section, there is a field for Resolution.  This seems to default to 240 pixels/inch. I know I change it and LR will adjust the exported image appropriately.  But if a photo has higher than 240 pixels/inch resolution, I don't really want LR downsizing it to 240.  Is there a way to tell it to export the file in inherent resolution of the file inside of LR?

5 replies

DdeGannes
DdeGannes
Community Expert
October 16, 2020

Ok I just wish to put things in a simple thought process. I just like to keep my thought process like KISS (keep it simple sweet).

Applications available LrC and Photoshop.

I have a raw file from my camera the default is 4608 X 3456 pixels. That is the source file.

I need to create a print 30"X 20", clearly I need to crop and resize.

I have an Epson printer to make the print, for optional print quality the printer will print at 720 DPI a Canon Printer at 600 DPI.

Proceed to edit the raw file in Lightroom, crop to dimensions 3x2, send to Photoshop for further editing if needed a tiff / psd will be saved to Lightroom. Now I have a file 4608 X 3072 pixels.

 

Go to Print module in LrC and select the dimensions of the print size i.e. 30" X 20" and allow Lightroom to manage the print not the Printer. (I am not addressing other issues like Color management). Proceed to print and Lightroom will resize to the necessary resolution for the printer to print at the necessary DPI (720). 
If I need to send a file to a outside source for printing, I would allow Lightroom to "print to file" resizing to the 30" X 20" at 360 psi to create the necessary file in tiff format.

Regards, Denis: iMac 27” mid-2015, macOS 11.7.10 Big Sur; 2TB SSD, 24 GB Ram, GPU 2 GB; LrC 12.5,; Lr 6.5, PS 24.7,; ACR 15.5,; (also Laptop Win 11, ver 24H2, LrC 15.0.1, PS 27.0; ) Camera Oly OM-D E-M1.
Todd Shaner
Todd Shaner
Brainiac
October 13, 2020

Not sure how you managed to clear the Resolution value as 1 is the lowest number it will except. You can check 'Resize to Fit,' change the Resolution value to whatever you want, and then uncheck 'Resize to Fit,' Why do you see this as an issue after what we've explained to you?

kentmcpherson
kentmcphersonAuthor
Inspiring
October 13, 2020

As I mentioned, Resize to Fit was not checked. I didn't turn it on and then off.  It was just off.  I changed the Resolution value by double clicking it and pressing Delete.  Then did the export.

 

I care because when I give someone a photo to print, doesn't the resolution matter?  For example, in LR itself if I use the Print module, it will show me at my desired print size, e.g. 11x14, the ppi value is X;  in this case with this file, it says 259dpi at 11x14.  If I wanted to print larger, the dpi might drop below 240. e.g. a 17x24 size the dpi is only 178 which might not provide the best quality print.  Maybe I have to create different files for different size prints.  Still trying to figure it all out but it seems like a single file might not be the right approach.

 

D
dj_paige
Brainiac
October 13, 2020

If your photo is 4269x2846, it will print at 240 pixels per inch giving you a print of 17.7875x11.853 inches. The exact same photo, exported at 4269x2846 and the meaningless 240 pixels per inch in the resolution field will print at 300 pixels per inch at 14.23x9.487 inches. The exact same photo, exported at 4269x2846 and the meaningless 240 pixels per inch in the resolution field will print at 600 pixels per inch at 7.115x4.743 inches.

 

The number you are trying to assign meaning to in the Export dialog box is meaningless.

Todd Shaner
Todd Shaner
Brainiac
October 13, 2020

"Doesn't this mean that if I try to print this file, the max resolution I get is 240 pixels/inch?"

 

No, the actual print size is determined by your LrC Print module or printer driver settings. As dj_paige mentioned the Resolution value is only used in the LrC Export module when 'Resize to Fit' and in or cm are selected. You would use these settings when creating a output file that will be sent to an outside printing service by entering the desired print dimensions (in or cm) and the recommended resolution from the printing service (usually 300 ppi).

    kentmcpherson
    kentmcphersonAuthor
    Inspiring
    October 13, 2020

    Todd, I have not checked Resize to Fit.  See below.  I've even deleted the Resolution value. But the resulting print comes up with the dimensions in my earlier post, i.e. 240x240 Resolution.  LR must default to 240 if you don't specify.  What am I missing?

    R
    richardplondon
    Community Expert
    October 13, 2020

    It is part of the specification for a JPG image (possibly for other types of image as well) that some Resolution value is compulsory. Whether the particular value entered, is actually useful to anyone or not: Lightroom happens to default to 240ppi just to put something in.

     

    • If you un-check resizing then you just export whatever pixels there natively are (and PPI is incidental).
    • If you resize to a stated number of pixels wide/high, that is what is exported (and PPI is incidental).
    • If you resize to a stated number of inches wide/high, then PPI comes into play in order to help define the number of pixels that are to be exported: which is simply, one number multiplied by the other.

     

    If the result of this resizing reduces the number of pixels below what's coming from the camera original, that is a simplification / reduction of the picture detail included. That affects the detail content achievable for any prospective print or on-screen viewing.

     

    If the result of this resizing is to define more pixels than what's coming from the camera original, no extra picture detail can be invented so this is merely an equivalent "re-stating" of the full original detail that would have been seen without resizing.

      Per Berntsen
      Per Berntsen
      Community Expert
      October 13, 2020

      The real "resolution" of an image file is its pixel dimensions.

      Ppi is optional metadata, and is only used for printing. An image can exist without a ppi value at all, and for screen viewing, the ppi value has no effect – the image will display on screen according to its pixel dimensions regardless of the ppi value.

       

      To calculate print size, divide the pixel dimensions with the ppi.

      Your image is 4269 x 2846, so at 240 ppi it will print at 17.78 x 11.85 inches.

      If you want to print an image at a particular size, choose inches (or cm), and enter the desired ppi value.

      Lightroom will do the math for you, and export at the correct pixel dimensions.

        D
        dj_paige
        Brainiac
        October 13, 2020

        Uncheck "Re-size to fit".


        Also, resolution has no impact on the exported file, unless you choose a dimension in inches or centimeters.

          kentmcpherson
          kentmcphersonAuthor
          Inspiring
          October 13, 2020

          I don't have anything checked in the Image Sizing box at all. I chose no dimensions but LR filled in the 240 resolution.  See below.  Doesn't this mean that if I try to print this file, the max resolution I get is 240 pixels/inch?

           

          D
          dj_paige
          Brainiac
          October 13, 2020

          "I chose no dimensions but LR filled in the 240 resolution. See below. Doesn't this mean that if I try to print this file, the max resolution I get is 240 pixels/inch?"

           

          NO

           

          If you have not checked "Resize to Fit", you get full resolution, every single pixel, that is in your photo (or if you have cropped it, every single pixel in the cropped area).

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