Lumenzia: Apply Masks
The "apply" buttons are designed primarily to apply the orange preview layers or a lasso selection (any orange button can be used with the orange preview layers). This allows you to turn the previews into a selection, mask an existing layer, or create several different types of new layers and apply a mask to them. Additionally, the apply layers can be used without any mask preview (for example to sharpen the whole image or apply a general vignette).
Overview of Applying Masks
The "Sel" button has a few purposes: (1) to load orange preview layers as a selection, and (2) to save and reload selections.
Add, subtract, or intersect selections.
This shortcut (<alt> / <option>) will help you invert a selection or mask easily during both the preview and apply phases. This feature is particularly helpful to protect highlights / shadows (by selecting everything but a dark/light mask), or to protect a small area (by inverting the selection when using a group mask).
Use paths as an input to isolate your masks (works similar to using lasso selections).
Reduce the size of your files and abe her non-destructive workflows by converting lasso selections and paths to vector masks.
Contrast: Local Contrast Enhancement
The "Contrast" button is designed to quickly and easily increase contrast in a targeted area, without adversely impacting other parts of the image.
Create a custom vignette.
Dodge / Burn
Quickly create a new dodge/burn layer and load any luminosity mask preview.
Increase (or decrease) saturation with very natural results.
The "Sharp" button in Lumenzia gives you access to multiple forms of sharpening. While they are listed as being optimal for landscape or portrait, you can use either for any subject.
Note: The non-destructive Sharp video shows a much older version of the sharpen interface, but the behavior is the same.
Edge Protection (Sharpen)
Sharpening can create halos around high contrast edges. The "Edge Protection" feature inside the sharpening dialog is designed to help mask out these halos.
Mask, +, and -
Mask will replace any existing layer mask.
The +/- buttons will add/subtract the current preview/section to/from the active layer's mask to help refine the mask. For example, you can select L2 and then subtract L6 to remove blown highlights from the mask.