[Gimp-user] At 100%, my selection hasn't the size it should have

[rich404 <forums gimpusers com>]

> Tell me if I'm wrong, but this time, when the second layer will be
> scaled in place, there will be a loss of quality of the second layer ?
> This loss of quality is due to the scaling, which is intrinsic to the
> tool whether you scale up or down. It also depends on how much the
> scaling is important no ?

If you need to combine 3 images into one image somehow and two of those need to
be scaled to match, then you will have to accept that scaling down throws away
some pixels and scaling up guesses added pixels. You have an additional factor
in that the original image(s) are jpeg and there can be jpeg artifacts along
edges.

I saw your other post and while the reply was very detailed there is not
indication of the amount of scaling and the algorithm used. Gimp choices are
None - Linear - Cubic - Sinc(Lanczos3) Usually Sinc is better than the default
Cubic.

If the amount of scaling is large say 50% down to 25% then it is customary to
give the image a pre-blur using Gaussian blur with a suitable radius value ( 2
for 50%, 4 for 25% ) In my opinion not worth scaling to less than 50%.

Always difficult to give a proper answer when working in the dark. I have no
idea of the nature of the images you are using.

-- 
rich404 (via www.gimpusers.com/forums)