It is this bit I was commenting on. You do not have to keep resetting your chosen interpolation method
However, while linear interpolation is faster than the better quality more recent methods, it has little to do with the original post.
A 5000 x 4000 pix flattened image, so 1 layer, then scaled down 36 % takes 5 minutes.
A quick test here: similar sizes, 20 layers flattened. In memory showing 1.4 GB Using noHalo interpolation takes 3 seconds.
I would suggest that the OP problem is more that the interpolation method.
Quote:...Unfortunately, after the interpolation is changed manually to 'Linear' and GIMP is closed, 'Cubic' comes back as a default after restarting GIMP. It has to be changed manually every time after closing GIMP.
However, while linear interpolation is faster than the better quality more recent methods, it has little to do with the original post.
A 5000 x 4000 pix flattened image, so 1 layer, then scaled down 36 % takes 5 minutes.
A quick test here: similar sizes, 20 layers flattened. In memory showing 1.4 GB Using noHalo interpolation takes 3 seconds.
I would suggest that the OP problem is more that the interpolation method.