Modifiers are the most advanced feature of Producer. They’re not well documented so, much relies on your knowledge and understanding of how Producer works. That generally means advanced users will be the ones experimenting with and using them.
Modifiers allow the user to perform effects that would be otherwise impossible or extremely difficult and time consuming to do. As such, they can be an extremely powerful. However, there are limitations to what they can do. There is no hierarchical processing of actions (for example, a math equation may use parenthesis to control the order of a calculation). A value of the layer may not be directly multiplied with the value of another layer (a intermediate layer is required at this time). A modifier only applies to a set of keyframes (e.g., keyframe 1 and keyframe 2) or all keyframes. It cannot apply to a range of keyframes (e.g., keyframes 1 through 4 of a set of 6), except indirectly.
That said, modifiers are just another tool to help you display the images in your slideshow. The effects you create on your images can be simple (panning, for instance) or complex (multiple functions applied such as sine/cosine with panning, or a multiple set of actions across a set of different features: panning, zooming, rotation, opacity, blur, brightness, etc). They can automate tedious operations or reduce the workload of adjusting an effect you’ve created to display your image(s).
Modifiers “modify” a value that you’ve entered into Producer. They work either by single actions or multiple actions, where an action is simply a line that changes/modifies a Producer value. Modifiers can work with multiple layers to create values that a specific layer can use (that is, intermediate results are created with modifiers on intermediate layers).
To get the basic introduction to Modifiers, hit F1 in the main Producer program window, and search for Modifiers.
This section should provide some helpful tips and hints on using modifiers in your shows.