Today’s Question: Is there a difference in image quality in Lightroom Classic CC if you scale a photo versus cropping?
Tim’s Quick Answer: No, the final result will be the same in terms of image quality. Scaling essentially provides the same basic capability as cropping, though without as much control over the actual cropping of the photo.
More Detail: As I imagine most photographers are aware, Lightroom Classic CC provides a non-destructive workflow. That means that when you apply adjustments in the Develop module, you’re not actually altering the original source image. Instead, you’re effectively applying metadata updates to the image, and having the preview updated to reflect the changes.
The actual effects of your adjustments don’t get applied to the image until you create a copy of the image for sharing, such as by exporting or printing. At that point the actual changes in appearance will be reflected in the output you create.
The Scaling feature available for the Transform adjustments enables you to effectively zoom in (or out) on the photo. This would make it possible to zoom in on the image in order to crop it, so that a warped edge of the image can be cropped out.
Whether you use the Scaling adjustment or the Crop tool in order to crop the image, the final resizing of the image will be the same, and so the quality will be the same. The only real reason to choose the Crop tool over the Scaling adjustment is control.
With the Crop tool you can adjust the aspect ratio, and also fine-tune all four edges or corners of the photo independently. This provides considerably more control over how the image is actually cropped. However, if you’re able to achieve the desired cropping with either approach, the image quality will not be worse with one over the other.