Re: [Gimp-user] Change background colour with GIMP 2.10.22

[Zoltán Kluik <numizmatikakz gmail com>]

Dear GIMP users,

I would like to ask your help regarding removing background and change it
to white.
I'm dealing with coin pictures mainly medieval silver coins. I take the
photo about coins with green / dark green background. In the past on Ubuntu
I used the GIMP 2.8.16 version where I applied the foreground selection
tool. Here I just simple rounded the coin, press enter and the program
after some seconds selected my coin. I loved this method, because it takes
only seconds to select the coin.

Last year I have upgraded GIMP to version 2.10.22, but from this time I
have a big problem with time consumption and also with the quality of the
changing the background. Now in 2.10.22 I open a picture, using foreground
selection tool, but in this version there is a motor feature where I can
select Global- and Levin matting. I use both with iteration value 1. First
Global is selected, coin is rounded, pressing enter, selecting the
foreground with the mouse, again pressing enter. Here the problem is that
under the coin where the green background’s colour was a little bit darker
there are green dots. So after Global,  I apply the Levin matting. With
this the dots are deleted, good, but where it is not selected the coin,
there the surface (mainly at the edge) is not the original, blurred or not
as the original was. Here I can use the adding to background selection or
adding to the background within extra zoom possibility to make sharper the
edges. Finally after 10 minutes however it is the same result as in 2.8.16
was 30 seconds and automatically.

So what did I wrong or how I should do to make this process easier and
faster as it was in the earlier version?

Thank You in advance for Your advice!

Zoltan

Zoltán Kluik <numizmatikakz gmail com> ezt írta (időpont: 2021. márc. 23.,
K 14:10):

> Dear GIMP users,
>
> I would like to ask your help regarding removing background and change it
> to white.
> I'm dealing with coin pictures mainly medieval silver coins. I take the
> photo about coins with green / dark green background. In the past on Ubuntu
> I used the GIMP 2.8.16 version where I applied the foreground selection
> tool. Here I just simple rounded the coin, press enter and the program
> after some seconds selected my coin. I loved this method, because it takes
> only seconds to select the coin.
>
> Last year I have upgraded GIMP to version 2.10.22, but from this time I
> have a big problem with time consumption and also with the quality of the
> changing the background. Now in 2.10.22 I open a picture, using foreground
> selection tool, but in this version there is a motor feature where I can
> select Global- and Levin matting. I use both with iteration value 1. First
> Global is selected, coin is rounded, pressing enter, selecting the
> foreground with the mouse, again pressing enter. Here the problem is that
> under the coin where the green background’s colour was a little bit darker
> there are green dots. So after Global,  I apply the Levin matting. With
> this the dots are deleted, good, but where it is not selected the coin,
> there the surface (mainly at the edge) is not the original, blurred or not
> as the original was. Here I can use the adding to background selection or
> adding to the background within extra zoom possibility to make sharper the
> edges. Finally after 10 minutes however it is the same result as in 2.8.16
> was 30 seconds and automatically.
>
> So what did I wrong or how I should do to make this process easier and
> faster as it was in the earlier version?
>
> Thank You in advance for Your advice!