Creating the Initial Gradient|
Initially, create a new gradient with plenty of knots. Then simply capture the gradient from an image. Remember, you can view how the captured gradient looks using one of the in-built texture generators. The two handles for the gradient sample in the image window can be adjusted with instant feedback allowing the gradient capture to be fine-tuned.
Using the Gradient in Darktree|
Once you have your gradient it is a simple task to use it directly in Darktree. Just add the Enhance:DT GradientPercent as a color component and attach the input to any percentage component. A background can be added and use can be made of the alpha channel in the gradient allowing any number of layering options to be created. Alternatively, you can use the gradient or its alpha channel as a percentage to control any aspects of the shader component.