GradientXTerminator was created by Russ Croman to remove gradients
from astronomy related images. The procedure on this page uses the
software to enhance a dark area of an image. This for the "pretty
picture" astro-artist and not the faint of heart purist.
shows an image that has a darker region of nebula on the right side that
is difficult to show without making the left side too bright.
The first step, with PhotoShop, is to copy the image to a new layer.
This is easily done with the Ctrl J shortcut.
Then use the Lasso Tool, to select the
bright part of the central nebula. See Figure 2.
Next, invert the selection... see Figure 3. So far we are
following the standard GradientXTerminator process.
Now execute GradientXTerminator with the Detail set to Fine and the
Aggressiveness set to High. See Figure 4.
Figure 5 shows the result after executing GradientXTerminator.
The final step is to set the blend mode to Lighten and flatten the
image. See Figure 6 for the final result. You can blink Figure 6 back
and fourth from the starting image to the final by rolling your mouse
over the image.