Removing purple fringe and chromatic aberration

[shikamu]

It is my understanding that there are 2 types of chromatic aberration:

1. lateral (transverse)
2. longitudinal (axial)

I have read that the LrC Remove Chromatic Aberration option can remove lateral, but not longitudinal. Sometimes if you switch to the Manual tab and carefully by trial and error adjust the Defringe color sliders you can remove some of the longitudinal, but I have found that it often works poorly and will also change similar non-chromatic aberration colors in the photo to monochrome also.

Sometimes in photos I get purple fringing, especially things that are against a bright background (sky, etc.).

Recently I noticed in the masking tool that there is a Defringe control in the Detail section. I tried it on some purple fringe and it seems to do a good job most of the time.

Sometimes the purple fringe is in various places so you must use the brush to mask multiple areas before using Defringe. I then wondered if I was to make a Gradient mask that covered the whole image if I could then turn Defringe up and it would get rid of the purple fringing anywhere in the photo, but not cause harm elsewhere. I tried it on a couple of photos and I didn't see any harm elsewhere. Maybe I was just lucky in those 2 photos though. I will try some more.

I have a couple of questions:

1. Is there any harm in always having the Remove Chromatic Aberration turned on for all photos?
2. Is there any harm in doing like I said above about having a Gradient mask covering the whole photo if there is purple fringing and then using the masking Defringe control?  Is there any downside to doing it this way?

[Ian Lyons]

Lightroom Classic edits are non destructive. You can reset any edit or all edits any time you choose. If you choose full reset, then file will return to its original state.

Is there any harm in always having the Remove Chromatic Aberration turned on for all photos?

No. It's really up to the user to decide whether they believe that CA correction is applicable or not. In some cases it may not be and in others it may be necessary.

Is there any harm in doing like I said above about having a Gradient mask covering the whole photo if there is purple fringing and then using the masking Defringe control?  Is there any downside to doing it this way?

No to both questions. If the results on a particular image are to your taste, then use the approach you describe. If not, then just reset the adustment or step back in history.