how to remove background residual after DBE

[blackdragon72]

In one of my image, after DBE there is still some residual visible with auto stretch, not perfect but acceptable. It means that after HT it also shows up, and eventually becomes much worse. So what is the best time to fix it, and what process shall be used?

[georg.viehoever]

Apply DBE multiple times. Play with the Tolerance value.
Georg

[blackdragon72]

Practically, what is the max # of DBE can be applied? Eg, whether or not excessive DBE will degrade image qualify, or can not improve residual anymore.

[georg.viehoever]

- In theory, it should be possible to apply it a large number of times without degradation.
- Usually, 2x or 3x is enough
Georg

[blackdragon72]

Thanks!

And I found out that the 1st DBE works better with "Divide" option than "Subtract".

[blackdragon72]

- In theory, it should be possible to apply it a large number of times without degradation.
- Usually, 2x or 3x is enough
Georg

For one of my images, I could not get flat background with DBE. The background was smooth but with visible gradient. DBE seemed to be able to detect gradient but could not get rid of it even after a few tries.
I used the same image with ABE, the background was much flatter.
What is main different between ABE and DBE? and what parameters I should try with DBE to get better background? I played with sample size and # of samples, they do not seem help.