In this last part of this tutorial, we are going to add a simple frame to our image. One way to do this is to create a solid color layer (which will become the frame) and then clip out a transparent area in the middle of the image through which the other layers below may be seen.

• Add a new, fourth layer, name it Frame, and remove the transformations on the Mapping tab.
• Click on the Formula tab of the Layer Properties tool window and replace the current (Newton) formula with the Mandelbrot formula in Standard.ufm.

Before we go on, notice the black area on the inside of the Mandelbrot figure. Up until now, in the images with which we have worked, we have only dealt with “Outside” points and “Outside coloring.” In this layer, we are going to work with the Inside points.

The coloring of inside points is controlled on the Inside tab of the Layer Properties tool window. Switch to the Inside tab and notice the Transfer Function setting. When the Transfer Function is set to None, the coloring algorithm is ignored and the Solid Color setting takes effect.

To see how this works, let’s change the solid color to something other than black.

• Click on the Solid Color swatch on the Inside tab. Click and drag the Luminance slider to 255, and note that the inside of the Mandelbrot figure becomes solid white.