Editing and enhancing masks

Mask / Layers / Layer Adjustment

Masks can be edited and enhanced by a number of features like refining the edge of the mask or applying a feather to it.

Overview

Inverting a mask

The Invert Mask option is used to create a reverse selection of a mask. This is adopted, typically, when drawing a mask on a small area and reversing the selection to include the rest of the layer is the simpler option. The option can also be used to invert the Display Grayscale Mask so that the edge and the selection may be more clearly seen. The Invert Mask option is always used on a single layer, but it can be used to copy a selection to a second layer.

One common technique, favored by fashion photographers working on location, is to make the subject standout from the background using color to emphasize the distance between them. Although the human visual system can compensate for color differences under a mix of lighting conditions, it is hardwired into our subconscious that distant scenes such as mountain ranges always have a cool-blue look, while features much closer to hand have a warmer-look about them. This effect can easily be accomplished using layers and the Invert Mask option and the local Color Balance tool.

  1. Go to the Layers tool.
  2. Click-on the Create New Layer button (+ icon) in the tool’s foot bar to create the first adjustment layer, leave as Layer 1.
  3. With the layer selected in the Layers tool (indicated by an orange or silver-colored bar, depending on focus), select the brush tool (B) from the tool's foot bar and draw a mask on the subject that you want to isolate from the background.
  4. Verify the accuracy of the mask drawn, toggle Always display Mask (M) and tidy-up the mask as necessary. (Use shortcuts to switch between the brush (B) and eraser (E).
  5. To add a second mask with a separate adjustment, a new layer must first be created. Repeat step 2, leave as Layer 2.
  6. Click-on the Layers Action menu button (... icon), or ctrl/right-click on Layer 2, and select Copy Mask From > Layer 1.
  7. Repeat and click-on the Layers Action menu button (... icon), or ctrl/right-click on Layer 2 a second time, and select Invert Mask
  8. Double click on Layer 1 in the Layers tool to rename it. Add a meaningful name to aid organization, such as foreground or subject. Repeat for Layer 2 and add a relevant name, such as background.
  9. Select Layer 1 (foreground) and adjust the Color Balance tool, adding a warm color balance setting as desired.
  10. Repeat the process with Layer 2 (background) using a cooler, blue color balance setting, or a use a suitable preset.

Filling in a selection

The Fill Mask option enables you to quickly fill-in an outline drawn with the brush. It's an ideal aid to your workflow when working with large selections, particularly when there are areas that require intricate brush-work. Simply select the brush, draw around the edge of the area that you want to mask, then use this option to complete the selection. If there are multiple areas on a layer, the Fill Mask command will fill each. If you haven’t drawn an outline, the Fill Mask will completely fill a layer with a mask (like the New Filled Layer option), which is useful when brushing away adjustments is the simpler option.

  1. From the Layers tool, long-press on the Add or Erase Mask button and select the brush using the Draw Mask (B) option. Repeat and select the Always Display Mask (M) option. 
  2. Carefully draw around the edge of the area that you want to apply the mask to; the outer edge of the brush stroke will form the edge of the mask. Ensure that there is a continuous outline around the area required.
  3. Go to the Layers tool and click-on the Action menu button (... icon) and select Fill Mask from the menu. The selection is filled automatically with a mask.
  4. Toggle the mask off using shortcut (M), or select Never Display Mask (M) option from the Layers tool.
  5. Apply the desired adjustments to the masked area.

Add a feather to the mask edge

The Layers tool offers a feather mask feature, which enables you to expand the width of the mask’s transition border after the mask has been drawn. The Radius slider determines how broad the blending along the edge of the mask will be and is measured in pixels. It is especially useful when masking elements of images with indistinct edges from high noise levels or low contrast.

In general, start with the default setting, enable the Display Mask (M) and set the image magnification to 100%, actual pixels, then gently move the slider to the left for a smaller radius and thinner, more defined and accurate edge, or to the right when working with an uneven edge or a smoother look is required. The tool only affects the mask(s) on the selected layer and doesn’t work with offline images. Note that while you can use the Feather Mask feature on any Radial Gradient Mask or a Linear Gradient Mask, you will be prompted to rasterize the mask once you click Apply. You will be able to see and adjust the feathering effect before you commit, but you cannot readjust the Radial Gradient Mask or the Linear Gradient Mask itself once you have added the feathering. Because of this, it might be a better idea to adjust the feathering directly on those two types of masks by dragging their control lines.

  1. Go to the Layers tool and right-click on the layer in the list that you would like modify.
  2. Select Feather Mask… from the list. The Feather Mask dialog window will open.
  3. Drag the Radius slider to the left, beneath 10 (default) to reduce the feathering effect, above to a maximum of 100 to increase. The image will be updated with the effect in the Viewer. Toggle the Display Mask option on and off to view and hide the mask overlay.
  4. Click Apply to confirm the setting or Cancel to reject it. If you are working on a Radial Gradient Mask or a Linear Gradient Mask, you will be prompted to rasterize the mask once you click Apply.

Refining the mask edge

The Layers tool offers a refine mask option, which enhances the precision of the mask along the border. When applied, the tool affects all the masks in an individual layer, whether that’s one or several. The Refine Mask tool’s edge-detecting technology makes it ideal for fixing edges, creating accurate and clean selections of complex elements from backgrounds, such as when masking hair or fur, or other objects with intricate or fine details. It can also be used to improve brush work along the horizon in landscapes and cityscapes, for example, as well as other elements with high-contrast edges. If the image has high noise levels or has low contrast, the Feather Mask should be used instead.

The Refine Mask tool should be used at the end of the workflow. However, it is typically an iterative process, and some tidying of the mask edge may be necessary using the eraser brush (E) before reapplying the Refine Mask command. Adjusting the Radius slider or text box alters the width or radius of the edge of the mask in pixels (px), with a range of 0-300 and a default of 10px. However, the tool will recall the previous set value. In general, start with the default setting, enable the Display Mask (M) or Display Grayscale Mask (Alt-M), then gently move the slider to the left for a smaller radius and harder, sharper edge, or to the right when haloing or other unwanted artifacts are observed and a slightly softer edge is required, with wispy hair, for example. The tool doesn’t work with offline images.

Note that while you can use the Refine Mask feature on any Radial Gradient Mask or a Linear Gradient Mask, you will be prompted to rasterize the mask once you click Apply. You will be able to see and adjust the refine edge effect before you commit, but you cannot readjust the Radial Gradient Mask or the Linear Gradient Mask itself once you have added the feathering.

  1. Go to the Layers tool and right-click on the layer in the list that you would like modify.
  2. Select Refine Mask… from the list. The Refine Mask dialog window opens.
  3. Drag the Radius slider to the left, beneath 10 (default) to improve the quality for hard, clean edges, or above to the right to a maximum of 300px for softer edge transitions when masking fine detail such as hair. The image will be updated with the effect in the Viewer. Toggle the Display Mask option on and off to view and hide the mask overlay.
  4. Click Apply to confirm the setting or Cancel to reject it. If you are working on a Radial Gradient Mask or a Linear Gradient Mask, you will be prompted to rasterize the mask once you click Apply.