What is non-destructive editing, exactly?
When you save a JPEG or single-layer TIFF image after editing, all the data from the original file is discarded and re-written.
So once you have closed the image all of the original data is lost. When you edit a raw file the new settings are stored alongside the original data.
These settings can be inside the file, or stored in a separate file, which is used by the editing software to remember your last settings.
Some programs, such as Photoshop Lightroom, offer a similar option for JPEG and TIFF files, storing the editing information along with the original file so that you can revert back to the un-edited image at any time.
This is true as long as you don’t overwrite the original file with a new one when you finally develop or export the images from Lightroom.
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