Today’s Question: Is there a compelling reason to save the source images after they have been merged to make an HDR [high dynamic range] image in Lightroom Classic? My main reason for asking is that I use the Nikon D850 which creates large files and, while I understand storage is cheap, I just don’t see a reason to keep the source files since I can make further post processing changes to the HDR image.
Tim’s Quick Answer: Once you have created an HDR image based on bracketed exposures and confirmed there are no issues with the resulting DNG file created by Lightroom Classic (or Adobe Camera Raw), I would say there is not a critical need to retain the original raw captures used to create the HDR image. That said, I do personally prefer to retain those original captures “just in case”.
More Detail: Deleting an original raw capture file is often compared to throwing away a slide or negative (for those of us who remember the days when photography was only film-based). However, in the context of assembling an HDR image or a composite panorama from a set of original captures, this analogy doesn’t quite hold true.
When you assemble an HDR image in Lightroom Classic based on a set of bracketed raw captures, the result is an Adobe DNG file. That means in some ways you’re creating a raw capture that is a blend of several other raw captures. You have the same overall flexibility for making adjustments to that DNG file as you would for the original raw captures.
Therefore, there isn’t a significant reason to retain the original raw captures after creating an HDR based on those captures. However, there are a couple of things you’ll want to consider.
First, you’ll want to carefully evaluate the HDR image to make sure there are no quality issues. For example, if there was movement within the frame there may be ghosting artifacts, where a moving subject appears ghosted within the image. It is also possible that there would be alignment issues between the individual captures. So, zoom in and evaluate the overall image to make sure there are no quality issues in the HDR result.
Second, keep in mind that while software for processing raw captures has gotten rather mature, there is still the potential that new software updates will provide an advantage in terms of going back and re-processing the original captures into a new HDR result. I don’t consider this a serious concern, but it is worth giving some thought to.
I still retain my original raw captures even after blending them into an HDR result, but that is in large part just a state of mind on my part. It has been a very, very long time since I’ve gone back to re-process the original raw captures to a new HDR image after having created an HDR image that I was initially happy with.