Crop to Pixel Dimensions


Today’s Question: I need to crop an image to specific measurements (pixels) on each side [in Lightroom]. I can see the image dimensions in the Library module but the crop tool is in the Develop module. So as I adjust the crop I have no idea what the image side measurements are. Other than switching back and forth between Develop and Library on a trial-and-error basis is there a more efficient solution?

Tim’s Quick Answer: In this case I recommend cropping to the desired aspect ratio for the final pixel dimensions, and then exporting the image sized to the specific pixel dimensions you need for the final result.

More Detail: When you crop an image within Lightroom, you aren’t actually making changes directly to the source image. Instead, you are simply applying adjustment settings within Lightroom, with the preview image updated accordingly. It isn’t until you export an image that the adjustments are truly applied to pixel values. In other words, it is the exported image you want to focus on here.

Therefore, you can think of this as a two-step process. First you can use the Crop tool in Lightroom’s Develop module to apply a crop based on the desired pixel dimensions. Note that if you prefer you can create a Virtual Copy first, so that you are applying the crop to a second version of your master photo.

After selecting the Crop tool, you can click the popup to the right of the Aspect label, and choose “Enter Custom” from the popup menu. In the Enter Custom Aspect Ratio you can then enter the pixel dimensions you want to use for the final image in the two fields provided. Enter the width as the value in the left field and the height in the right field. Click OK to apply the aspect ratio change. You can then fine-tune the overall crop for the image based on the aspect ratio you’ve established.

Next, return to the Library module and click the Export button at the bottom of the left panel. Within the Export dialog you can specify the specific settings you want to use for the image file that will be created as part of this process. In the Image Sizing section be sure the “Resize to Fit” checkbox is turned on. Then select “Width & Height” from the popup to the right of the checkbox, and enter the desired pixel dimensions in the “W” (width) and “H” (height) fields. Make sure the popup to the right of those fields is set to “pixels”.

After confirming all of the other settings you can click the Export button. The file that is created as part of this process will have been cropped and resized to the specific pixel dimensions you needed, based on the settings for the Crop tool and within the Export dialog.