One way to get the most out of Photoshop masks that are based on pixel level data, like luminosity masks (where pixel luminance is the data source), is to always keep these masks in mind when solving problems or making adjustments in Photoshop. And the easy way to do that is to simply focus on the three basic characteristics that make up each pixel: Hue, Saturation, and Lightness. If the adjustment you have in mind or the problem you’re trying to solve can be isolated based on one of these three characteristics, then a mask from the TK8 Multi-Mask module might be of use. TK8 makes masks that target each of these characteristics as explained below.
Hue (or color)–If specific colors in the image need adjustment, an Infinity Color mask or Black & White Adjustment Layer mask can be used. Both make excellent masks that target specific colors in the image.
Saturation—Saturation masks are based on pixel-level saturation values. The more saturated the color, the lighter the pixels are in the mask. Inverting the base Saturation mask provides access to Vibrance masks, which are brightest in the unsaturated colors in the image.
So, if you examine your image in terms of its Hue, Saturation, and Lightness, then it’s easier to pick the right type of mask for what you want to accomplish. As an example, I recently had an email discussion with a TK8 user on alternate ways to make image vignettes. TK8 Combo and Cx modules use an adjustment layer set to Multiply blend mode and a layer mask to provide darkening at the edges of the image. The amount of vignetting can be controlled by changing the layer’s opacity. The user’s concern was that this method sometimes made dark colors too saturated or too dark. Yes, this is a potential problem with any vignette, especially if the image’s edges already contain saturated or dark colors. My usual solution had been to paint black at varying opacities on the layer mask of the vignette adjustment layer to conceal the vignette in areas where it affects saturation or darkens the image too much.
In the Quick Tip video below, Sean Bagshaw demonstrates an even better method and it’s a good illustration of the how to think about adding pixel-based masks to the workflow. The user’s main concern was that dark colors were sometimes being affected too much by the vignette. So the question then becomes: Is there a way to select dark colors in the image using a mask? Well, yes, of course, there is. That would be a Darks-series luminosity mask. So the next question becomes how to use a luminosity mask to subtract the dark colors from a vignette so the dark colors are less affected by the vignette. The video shows how easy this is while still creating a really nice vignette.
One of the nice things about using these pixel-based masks is how perfectly the effect is revealed in the image with no visible edges or halos. In the example of the Freehand Vignette in the video, the vignetting still looked perfect even after Sean increased the opacity of the vignette layer. Seamless blending is one of the defining characteristics of pixel-based masks, so using them provides considerable latitude in the degree to which pixels selected by the mask can be adjusted before creating unwanted artifacts.
Summary: Think about Hue, Saturation, and Lightness when deciding if a pixel-based mask or selection would be useful in the post-processing workflow. If one of these characteristics helps isolate the areas that need adjustment, then the TK8 Multi-Mask module can be used to generate and refine a mask to better target the adjustment to where it’s needed most.
Extra Credit Challenge: Sean used the TK8 Mask Calculator to create an ideal vignetting mask. Can you think of a way to use TK8 to paint the same effect directly onto the layer mask WITHOUT using the Mask Calculator?