Luma Range Masking Pro

Layers / Layer Adjustment / Mask

Luma Range is a powerful masking feature that will let you use luminosity values to control which part of the image a Layer-based adjustment should affect.

Introduction

With the Luma Range you can specify that for example only the deep shadows, a midtone range, or the upper highlights should be included in your selected layer adjustments.

Let’s take an example. You have created a new filled Layer and increased Clarity and Saturation a lot to boost the image presence. However, you might find that the effect is a too strong in the shadows and highlights. With the Luma Range feature, you can tell Capture One 12 to exclude the shadows and highlights from the adjustment, and only include the midtones.

You control the luminosity range with the black and white Range points at the top of the Luma Range graph. The gray area in the graph presents which luminosity values that are included in the adjustment, while the black area presents those that are excluded.

The two Falloff points at the bottom of the Luma Range graph control the transition from full effect to no effect. It is important to have some Falloff to prevent an abrupt transition from the included to the excluded luminosity areas as you can otherwise get artifacts.

See the illustration on the right to get a visual summary over how you should setup the Luma Range to include only the deep shadows, a midtone range, or the upper highlights, respectively.

The possibilities are vast since the Luma Range feature works on all Adjustment Layers. The only thing to remember is that you need to have some kind of mask created on a layer before you will see any effect of the Luma Range feature. It works on all types of masks like the non-destructive Linear Gradient Mask and Radial Gradient Mask as well as masks created with the Draw Mask cursor or a mask covering the entire image created with the Fill Mask or New Filled Layer commands.

It is important to point out that the Luma Range works on top of a normal mask; only the masked areas will be considered when applying the luminosity range. It is meant as a further refinement, and this is what makes the feature so powerful: You have two ways to control what should be affected in the image; the mask itself and the luminosity range. You can also think of the Luma Range as a way to clip or clamp certain luminosity values.

Another powerful part of the Luma Range feature is the fact that it is non-destructive; you can always go back and readjust it later. You can even copy the Luma Range mask to other images and readjust the luminosity range after the fact on those, setting up a very efficient workflow.

It is also worth to point out that if you readjust how a Linear Gradient Mask or Radial Gradient Mask covers the image, the Luma Range feature will automatically update its influence on the resulting mask. Since these new making features are all non-destructive, you can copy those to other images and readjust the masking after the fact, potentially saving a lot of time.

Creating a Luma Range Mask Pro

As mentioned, you will need to have some kind of mask on a layer before you will see any effect of the Luma Range feature. You can actually create a Luma Range on an Empty Layer, but you will not see any effect before you apply some sort of mask.
  1. Go to the Layers tool. Long press the New Layer icon and select New Filled Layer. Alternatively, Long press the Mask icon and select Draw Mask (B), Draw Linear Gradient Mask (G) or Draw Radial Gradient Mask (T) and create a mask.
  2. Click on the Luma Range… button in the Layers tool (or select the menu Layer > Luma Range…)
  3. Enable Display Mask to see what parts of the image the Luma Range mask will affect.
  4. Set your desired Luma Range by dragging the black and white Range points at the top of the graph. Tweak the Falloff points to ensure that the transition from the included areas to those that are excluded are not too harsh. A difference of 20 between the Range and Falloff for each is a good start.
  5. You can invert the selected Luma Range with the Invert Range option. This basically flips the selected luminosity range, so if you have included only the highlights and then enable Invert Range, you will in effect exclude the highlights and include everything else. Note that this invert command only affects the masked area, not the whole image.
  6. It is possible to tweak the edge coverage of the Luma Mask further with the Radius and Sensitivity sliders. See below for details on this.
  7. Once you’re happy with the Luma Range adjustments, click Apply to close the dialog box.

Refining the Luma Range Mask Pro

The Luma Mask can in certain high-contrast circumstances introduce harsh transitions along the edge of the mask. These can be mitigated by tweaking the edge coverage with the Radius and Sensitivity sliders. Be aware that the two sliders work in conjunction: The Radius slider controls (in pixels) how broad an area the edge refinement should work on. The Sensitivity slider in turn adds an edge/contrast detection to the Radius value: If you set Sensitivity down to 0, you will just get a simple blur/feathering effect that is seldom useful. As you increase the Sensitivity slider, the edge detection mechanism will modify the feathering by excluding any high contrast areas found. At 100, it will work similar to the Refine Mask action. In most cases, the default value of 50 is the sweet spot, and you can concentrate on adjusting the Radius slider. A value between 0,5 to 1 pixel is a good starting point.

  1. Go to the Layers tool and select the desired layer.
  2. Zoom into the image at 100% to better judge the effect.
  3. Click on the Luma Range… button in the Layers tool (or select the menu Layer > Luma Range…
  4. Enable Display Mask to see what parts of the image the Luma Range mask will affect.
  5. Adjust the edge coverage with the Radius and Sensitivity sliders.
  6. Once you’re happy with the adjustments, click Apply to close the dialog box.

Tip: The default Mask Color Opacity is set to 50% which can make it tricky to fully evaluate how the Radius and Sensitivity sliders affect the Luma Range when you have the Display Mask option enabled. This can be changed under Preferences and Appearance. Click on Mask Color and ensure that Opacity is set to 100 percent. It can also be a good help to change the color to something garish, like pink. This will make it easier to see whether the Luma Range does indeed affect the areas you are intending.

Erasing parts of the Luma Range Mask Pro

If you find that the Luma Range mask covers specific areas that you do not want to include in the adjustment, you can brush those out with the Erase Mask (E) cursor. As an example, you might want to affect the exposure of the bride’s white dress, but not her white teeth. Note that this particular workflow is meant to be used on a mask created with the Draw Mask (B) brush. It doesn’t work with Linear Gradient Mask or Radial Gradient Mask unless you accept to rasterize those. 

  1. Create a New Empty Layer and brush over the desired areas with the Draw Mask (B) cursor tool.
  2. Select the layer in the Layers tool and click on the Luma Range… button.
  3. Enable Display Mask to see what parts of the image the Luma Range mask will affect.
  4. Set your desired Luma Range with the black and white Range points. Tweak the Falloff points as needed.
  5. Click Apply to close the dialog box.
  6. Hit the keyboard shortcut M if the Mask overlay is not already showing in the Viewer.
  7. Select the Erase Mask (keyboard shortcut E) and paint over the areas that you do not want to include.
  8. If you make a mistake and remove too much from the mask, select the Draw Mask (keyboard shortcut B) and paint back over the area to include it.
  9. You can also add to the overall mask with Draw Mask but note that the Luma Range feature will always exclude the chosen luminosity values. If you have excluded white, you cannot add white areas with the brush. This is by design (see below if you want to override the Luma Range selection).
  10. Hit the keyboard shortcut M to toggle the Mask overlay off to review that your image adjustments are made to the desired areas of the image.

The advantage of the above workflow is that you can always readjust the Luma Range in combination with tweaking the mask (by erasing areas or paint them back in).

Overriding the Luma Range Mask Pro

If you need to include areas of the image that are not currently covered with the mask you should first try to readjust the Range and Falloff points as well as adjusting the Radius and Sensitivity sliders. If that doesn’t get you the desired result, you can change the Luma Range mask to be a normal pixel-based mask. You can then paint on it with the Draw Mask (B) or Erase Mask (E) cursor tools to add or remove areas, but note that once you “bake” the Luma Range settings into a pixel-based mask, you lose the ability to readjust it after the fact.

  1. Select the Luma Range mask by right-clicking on the Layer and choose Rasterize Mask….
  2. Add to the mask area with the Draw Mask (B) cursor tool
  3. You can also remove areas with Erase Mask (E) cursor tool
  4. Click on the Luma Range… button in the Layers tool to create a new Luma Range mask control, if needed.