One of the biggest frustrations I hear when photographers try to use exposure blending with luminosity masks to get beautiful skies is that they frequently get halos around hard edges such as the point where trees or mountains touch the sky. In my Exposure Blending Master Course, I teach several techniques on how to avoid halos in the first place. However, there are many times when you may still encounter halos for a variety of reasons, and it is important to know how to remove those halos easily.
With Lumenzia v8, you can now use the “Edge” button to do just that. It will quickly help you select the edge of any mask or selection so that you can paint white or black on your mask to remove the halos. See the video and the written summary below to learn how to save time and cleanly edges in your exposure blends.
Here’s a summary of the workflow to remove halos from the luminosity mask using Lumenzia:
- First, identify the cause of the halo.
- Are you seeing too much of the dark layer on top? Too much of the bright layer below? It’s critical to understand exactly what the issue is in order to know what fix you’ll need. Toggling the layers and masks off and on is an easy way to check.
- Once you know the problem, identify the solution you will need to do to the luminosity mask to remove the halo.
- Do you need to paint more white to reveal the dark sky layer, or black to remove some of the sky?
- Next, <ctrl/cmd>-click the luminosity mask to load it as a selection.
- The marching ants will show you roughly where the current edge of your mask is. Remember that the marching ants do not show pixels darker than 50% gray in the mask.
- Compare the rough edge of the selection to the solution you identified in the previous step. Do you need to select pixels which are inside or outside the existing edge? By how much?
- Use the “Edge” button in Lumenzia to convert the selection of the masked area into a selection of just the edge where you need to paint black or white.
- In the left side of the popup dialog, make sure “edges” is selected.
- Select a radius of about 1 or 2 pixels. It’s typically best to try starting with just 1 pixel, as painting outside the edge of the existing halo will likely just create a new halo.
- Select the number of pixels to expand (positive numbers) or contract (negative number) based on your evaluation from the previous step. Something between -2 and +2 is typically ideal. Due to the nature of this tool (with the radius and feathering), the edges tend to grow a little from where you think they are to begin. You also want to err on the safe side (so the center of the new selection shouldn’t go right over the halo, or the edges of the selection will go beyond it). Therefore, you will likely need to subtract about two pixels from what you would otherwise expect. For example, in the demo above would probably have guessed +1 pixel, but the correct choice was -1 to properly target the edge. So be sure to experiment with things a bit to find the best settings for your image.
- Click “Selection” to create the edge selection.
- You will be prompted to choose how much to blur the selection. The default generally works well, but you might try up to 1 or 2 pixels if you aren’t getting the results you like in the following steps.
- Given the work you’ve done to create this selection, now is a good time to click “Sel” and save the selection. If you need to create a couple different edge selections, this will be very helpful to switch back and forth.
- Now paint black or white as needed onto the layer mask through the edge selection you have created.
- If you aren’t getting the desired results in general, deselect and start over from step 3.
- If the selection works in some areas, but not others, repeat steps 3-5 as needed to create multiple different edge selections. If you have a complicated sky or foreground where the tonality changes a lot, you will likely need to use different selections for different areas of the halo.
- If you find a few pixels that stray outside your selection, don’t be afraid to paint free hand. This is quick and easy to do for small problems in the image. Just deselect (<ctrl/cmd>-D) and re-select (<shift><ctrl/cmd>-D) as needed to temporarily paint without the selection.