How to check brightness (exposure) spatial uniformity ?

[benoitvm]

I need to verify (and, if possible, adjust) spatial brightness (exposure) uniformity, on a set of home-studio photos taken with basic light setup.
Photos are from hand drawings on white flat rectangular sheets, and uniform exposure is important (but the available lighting set is a simple pair of 5600 LED spots, albeit carefully placed for subjective visual uniform exposure).
If needed, I may want to correct excessive brightness uneveness: what tool, beside some gradient matte ?
I'm still on PSP X9

[JoeB]

While this won't help with actually checking the brightness uniformity, if the uneven lighting if perceptually obvious than maybe some of the information in this thread might be useful to you in finding ways to make it more even:

viewtopic.php?f=56&t=64359

[Jean-Luc]

It is always better to take the correct pictures with the correct light.
Place a white paper, take the shot and measure the luminosity (RVB) in PaintShop Pro.
Move the spots until you get an uniform exposure on center and on each corner.
I know it will not be perfect but you will get less tweaking in post-production.

[bruce1951]

Jean-Luc if it was as simple as 'take thecorrect pictures' then there would be little need for photo editors!
Either fixing errors or having fun is why we have PSP isn't it?
Besides not all scenes are evenly lit.

bruce

[benoitvm]

Ha, apparently I didn't miss an obvious tool, much like e.g. a scope in video editing software: why isn't that included in PSP ?
(granted, I can simply import my picture in such video editing software and roundtrip with PSP to correct in trial-and-error mode )

[Jean-Luc]

Jean-Luc if it was as simple as 'take thecorrect pictures'

It is simple to take correct pictures...
You may use a correct lightmeter :
https://www.sekonic.com/

Years ago, I worked with a Gossen Lunasix when I needed to take photos from painted pictures in a studio. We did an incidend light measure on each picture corner and we moved the lights (spots) until we had equal luminosity on each corner.
I see you don't have such lightmeter. It is the reason why I suggested to do it with a white paper and the "lightmeter" from PSP (the Dropper)...

[bruce1951]

Jean-Luc it's 'simple' on a flat image etc. But many images suffers from dynamic range issues. This is when editing skills come into play. So it's always helpful to know how to extract extra details from either over or under exposed areas. And sometimes it's just nice to poke into the darker areas just for the fun of it.

bruce