Hi Graham,
Hope you're well! (except for that crappy weather...
)
Blending two images together should be pretty straightforward in StarTools, provided they are the same size (i.e. resolution).
It should just be a matter of launching the layer module with one image loaded and then clicking the 'Open' button to load the other. 'Blend' should already be selected by default and all you'd have to do is set the blend percentage (50% for a 50:50 blend).
StarTools is pretty strict when it comes to different sizes as avoiding stacking artifacts is paramount.
The StarTools Layer module differs quite a bit from traditional Layers in PhotoShop in that it focuses more heavily on transforming an image by building complex filters, and less on simple overlaying of graphics (for which PS is much more suitable and user friendly).
It was built to cater to professional image processing purists - the StarTools Layer module (more so when combined with a mask) allows you to do some pretty cool (and funky) things and emulate many different algorithms by chaining multiple operations together (Copy stores the Layer module's output in a buffer, while Paste->Foreground or Paste->Background pastes this buffer it into the new foreground or background respectively). It's the only module in StarTools that is not very beginner friendly, because it gives you 'VIP access' to a good number of the individual algorithms and filters that make up the different modules in StarTools.
That said, probably the most used Layers operation in StarTools is to blend a module's output with its input (by clicking the Undo->Foreground or Undo->Background) buttons. This allows you to control the strength of the last module's operation, reduce the noise of its output, exaggerate its output, use its output selectively, only use its output where it has added detail, etc.
Besides a vast array of options for the different blending modes (more than you'd find in PhotoShop) there are also a great number of filters that allow you to filter, enhance or mangle (parts of) your image to your heart's content.
If there is anything in particular you'd like to accomplish with Layers, let me know!
