There are a couple of hidden gems within the new Photoshop for Creative Cloud (Photoshop CC), and these are under the Filters/Other menu item. The two filters Minimum and Maximum are typically used to refine selection masks, but up to Photoshop CC were limited to squareness and to whole numbers only. Inside Photoshop CC both of these filters have been enhanced to support a bias toward roundness as well as squareness on the mask, as well as supporting decimals on the roundness preservation setting of each.
Here is a picture of a spoon that i shot in a Bhutan kitchen, and i may want to extract and include as part of another composition.
Using the Pen tool I am able to make a pretty good mask, but won’t be as tight to the object as i need it to be. Also, when i blend this into another image, there will most likely be some haloing on the around the edges.
For each pen path, I have created separate paths (under the paths panel), as the shapes/masks are slightly different (one is more square and one more round), which may be used later in the extraction .
Once the paths have been created, the selection for each can be made, first of all the handle. to make the selection from the path, select the path and right click it, or use the fly out menu on the paths panel.
I want to make sure that there is a feathered edge on the final selection, so that the mask that is created is not so aggressive.
Add a mask to the image to extract the handle, however, as the background layer is locked, I suggest duplicating the background layer (CMD+J on the Mac, CTRL+J on a PC), then select the new duplicate layer. Create a new mask on this layer by clicking on the new mask icon (at the bottom of the layers panel)
(I have also created a new layer between the background and the masked layer, so i can see the final effect)
To apply the filter, select the mask layer then use the menu item Filter/ Other / Minimum
The Maximum filter has the effect of applying a choke—spreading out white areas and choking in black areas.
The Minimum filter has the effect of applying a spread—spreading out black areas and shrinking white areas.
The Maximum and Minimum filters are useful for modifying masks, the filters look at individual pixels in a selection, within a specified radius. Maximum and Minimum filters replace the current pixel’s brightness value with the highest or lowest brightness value of the surrounding pixels, meaning that the feathered edge will be supported with these filters.
(There is another way of modifying the mask, and that is to use a Levels adjustment directly on the mask (this is different from using an Adjustment Layer). The levels adjustment won’t preserve the feathering as these filters do)
By default the settings will be “Preserve = Squareness” and the Radius set to 1. Ultimately the Radius size won’t be huge, but to demonstrate the feature, i’ll push it much higher than normal. By increasing the Radius to 30 pixels, the mask has been restricted and has taken on a bias towards preserving squared edges, which on a round section, isn’t desirable.
If the Preserve option is changed to “Roundness” (notice that decimals are also accepted into the Radius value), the bias on the mask (section highlighted in Red) is more towards preserving the round edge.
Once both selections have been completed the mask is tight to the extracted object, and has kept the feathered edge.