how to make a color transparent in GIMP


I realize there are a ton of questions like this, but they are all way overcomplicated for what I am trying to do.

What I want to do is very simple. I want the background of my image completely transparent, and the foreground completely opaque. My background is white while my foreground is a pale blue and gold. Whenever I use color to alpha I end up with the foreground being semi-transparent.

How do I make the background transparent without changing the transparency of the foreground?

7/28/2014 4:22:00 PM

Accepted Answer

Whenever we choose to change a color to transparent with the Layer > Transparency> Color to alpha tool we will also introduce semi-transparency of colors different to the selected. Below this is shown for making white in the background transparent:

enter image description here

In case this is not wanted we need to select only a single colored area for transparency. This can be done with the select by color tool enter image description here.

  • Make the threshold of selection low to zero to select only a single color.
  • Feather the selection for a smoother transition.
  • Add a transparent layer if not yet present (Layers > Transparency > Add Alpha Channel)
  • Clear (Edit > Clear or Del) the selected color to make it transparent:

enter image description here

7/28/2014 8:12:00 PM