I've just started scanning my families negatives. When I get the scan, it's a bit brighter than the print that was made that I can compare it to, but the print has less details in the dark areas.
Alas, if I bring down the exposure in post, I get an image more in line with the print, but instead those before mentioned shadows swallow some detail. Is there a right way do do it. Which is the "true" image?
I would say that "true image" is a fallacy. There is no true image. Match your scans to your prints if you want. I wouldn't. That's the point of scanning negatives – to draw out as much of the image as possible – more than the original print may show. Edit it however you want it to appear. Photo editing is intrinsically a subjective process.
I use Adobe Photoshop. If you do too, look into the "Curves" tool. I use it to adjust input/output highlights/shadows independently, and if desired you can operate on RGB channels independently. Any other good image editing software will offer the same feature (maybe under a different label).
Couple of links on the Curves tool:
https://www.cambridgeincolour.com/tutorials/photoshop-curves.htm
https://helpx.adobe.com/photoshop/using/curves-adjustment.html
Once you have a scan that contains detail in all parts of the dynamic range, you can tweak it in post processing. Lowering overall exposure is only one option. You can brighten or darken the dark and bright regions separately.
How to do this exactly would depend on your software.
