How to clear a .gif image from a filter by confronting with the original image

[Ambrus]

Hi!
Hi designed i simple "shutter" with GIMP, a layer painted with a brush and a level of opacity say of 30% I think. I saved the image in .png so I can import that image in an another program I use to work with gif animations.
I use no one, one or more of this shutter on each gif I work with.

The question is: If I have to remove the effect of the opacity layer I added to the gif animation as part of the workflow and I have the original .gif I can think of materially import in GIMP the original gif and the new one, and work some magic by confronting each and every frame of the two animation, one at the time...never ending story!!

So: There is a system to automate the process with gimp, confronting the new and variously worked gif with the original, maybe applying on the way a mask in small zones so in those zones they stay in the new form?
Thanks for reading me, hope to be enough understandable.

Thanks to all, have a nice day, night etc.
Ambrus

[Ambrus]

OK, I understand... corona virus has done more victims than expected. Sad, all dead.

[rich2005]

Not dead, not understanding the message.

Is it.
You added an overlay (png file) to an animation (gif file)
Now you want to use the same png file to remove the overlay from the animation.
You can do this on a one layer at a time basis but you want a batch process ?

then this

Quote: maybe applying on the way a mask in small zones so in those zones they stay in the new form?

What small zones ? Give a before and after example.

[Ambrus]

Thank you for your replay and please forgive me for my manners and my poor english.
Yes the first part you understood correctly.
A batch process to automate the work in all layers (one animation at the time) would be great.
Please do not take into consideration at all, the mask and small zones thing.
I think that a batch process wold do just fine. Can I find some instruction or tutorial to do the work manually, one layer at a time in a first .gif animation, so I can learn something about how to remove the overlay, and then, if possible, apply the batch process?
Thank you again
Ambrus

[Ofnuts]

If you found that applying your mask image again one one single frame with a given blend mode or opacity works, then you can use my ofn-interleave-layers script to do this on all layers.

But your mask likely obliterated too much data to make that possible.

[Ambrus]

Ok, I'll try in single frame first than we'll see. Thanks!!!