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

[Liam R E Quin <liam holoweb net>]

On Sat, 2021-03-27 at 00:31 +0100, Zoltán Kluik wrote:
> I have only point 9 which is not working. When I do Image --> Crop to
> content or Zealous crop the GIMP said: Cannot crop because the image
> is
> already cropped to its content.

So in that case maybe you don't need to crop the image?

If you still  do,  maybe there were some pixels around the edge that
were not selected.

An alternate workflow to using fuzzy select:

(4) use Rectangle Select to draw a rectangle around the coin, slightly
larger than the coin.
(4b) use Select->Invert so the edges of the image are selected
(4c) use fuzzy select on the gree but holding down SHIFT so that it
adds to the selection.
Now continue as before.

Or, if you prefer, when you get to cropping, if gimp gives that
message, use the Crop  tool from the toolbox to drag a rouch rectangle
around the coin. It doesn't have to be perfect (and you can adjust it),
as long as it doesn't touch the coin. Then press ENTER to do the first
crop.
After, you can use image->crop to content, and it should work OK.

slave liam


>  (Here the background is white and on the
> picture there is only the coin.)
> Thank You for Your help in advance.
>
> Zoltan
>
> Liam R E Quin <liam holoweb net> ezt írta (időpont: 2021. márc. 26.,
> P,
> 0:09):
>
> > On Thu, 2021-03-25 at 17:24 +0100, Zoltán Kluik wrote:
> > > Dear Liam,
> > >
> > > Yes, the image is in RGB colour 8 bit.
> > > What does it mean?
> >
> > Colour means as opposed to greyscale (just grey, no colur allowed).
> >
> > RGB means that any pixel can be in any colour, as opposed to
> > indexed
> > which would mean a fixed list of colours
> >
> > 8-bit means  each of red,  green, blue (RGB) can take any whole
> > number
> > value from 0 to 255 - this is appropriate for JPEG images for
> > example.
> >
> > With the following image I did this:
> >
> > (1) open the image in gimp
> > (2) select the Fuzzy Select tool from the toolbox
> > (3) in Tool Options, make sure the threshold is good - i used 13.
> > The
> > higher  this number ,the more the Fuzzy Select tool will select
> > colours
> > that are not quite the one you click on.
> > (4) i clicked on the green background 9still with fuzzy select).
> > This
> > selected eveything except the coin.
> > (5) i used select->grow to increase the selection by 2 pixels. This
> > makes sure that if e.g. there's a pet hair in the picture, it gets
> > selected out. But this also selects the edge of the coin, which we
> > don't  want.
> > (6) then, i did Select->shrinl and entered 1 pixel, to get back the
> > edge of the coin.
> > (7) Probably we don't want an ugly hard edge so i used Select-
> > > Feather
> > by 1.5 pixels to soften the edge of the selection.
> > (8) i did edit->cut (or Control-X), to remove the green. If you
> > don't
> > have the default black and white colours selected in the two small
> > panels  under the toolbox, press d to reset them to defaults and
> > then
> > do cut.
> > (9) then i did Image->Crop to Content, to get rid of the extra
> > white
> > areas.
> > (10) finally i exported the image.
> >
> > This is much faster to do than to describe. Maybe ten seconds at
> > most.
> >
> > Just before exporting ,i actually also used  Colours->Levelsand
> > pressed
> > Auto Input Levels; you may not want that; it makes the dark  parts
> > of
> > the image black. You can get a better result by including a photo
> > card
> > (you can get them on ebay or from any photography shop) in the
> > picture
> > and using the white and the black as white and black points in
> > Levels.
> > It's pretty  much instant although then you have to crop the photo
> > card
> > out of the picture.
> >
> > Interesting coin.
> >
> > slave liam (ankh)
> >
> >
> > >
> >
> > --
> > Liam Quin - web slave for https://www.fromoldbooks.org/
> > with fabulous vintage art and fascinating texts to read.
> > Click here to have the slave beaten.