Making Molecules

Step 1:

1. Create a new image, 150 x 150, 64M colours
2. Fill the background to black (this step is important). Set the foreground colour to white.
3. With the selection tool set to circle, draw a circle in the top left
4. Go to the fill tool, make the following settings:
   1. Fill mode to "Sunburst Gradient"
   2. Tolerance to 200
   3. Opacity to 100
   4. Options: Blend mode "lighten"
5. Fill the selected circle.

Step 2:

1. Now, move the selection (move tool, right mouse drag) or re-draw another selection circle to the right.
2. Switch to the fill tool and fill this selection.

   Because the "blend mode" on the fill tool is set to "lighten" then only those areas which are darker than the gradient colour coming in actually gets painted. That's what creates that lovely soft join.

Step 3:

1. Now repeat with a third circle. Circles can be of any size you like, or as many as you like.

Step 4:

1. Finally, switch to Colorise, or Adjust RGB to apply the colour scheme of your choice.

Tips: You can quickly switch between the fill and selection tools by pressing 'f' and 's' on the keyboard, makes working on this much quicker.

If you want to create more 3D like molecules, then you need to draw from the back forwards, so that near "atoms" overlay further "atoms".

I am indebted to Kai Krause who set me on the trail of this one.