Averaging multiple images

[tclune]

I want to do a simple thing, and I'm sure it's easy to do. But I run afoul of all the fancy options when I try to search for it. I want to simulate using a neutral density filter by taking multiple images and combining them into one -- I just want to average the multiple shots. The effect I'm after is like using an ND filter on a waterfall. I am using 64-bit PSP 2018. Help!

[Forriner]

You use an ND-filter if there's just too much light for your camera's shortest possible exposure time, or to create a long exposure. I don't know if there are any more recent discussions, but I remembered this one some time ago (edit: almost five years ago):
"Blending Multiple Images Together Simulating Long Exposure?"
https://forum.corel.com/viewtopic.php?f=56&t=59953

Perhaps there's something in there for you.

[tclune]

Thanks for the lead.