How to Create a Luminosity Mask in Affinity Photo
Posted on 19th June 2023
What is a Luminosity Mask?
A luminosity mask is a selection in an image based on the brightness of the pixels. Luminosity masks are created using an algorithm that looks at the brightness of each pixel and selects a range of brightness values. The selection can be based on the total brightness of the image, or on a specific brightness range.
Luminosity masks are used in image editing to make precise selections based on the brightness of the pixels. For example, a luminosity mask can be used to select all the pixels in an image that are brighter than a certain value. This can be useful for making adjustments to only the bright pixels in an image, or for removing objects from an image that are brighter than the background.
How to Create a Luminosity Mask in Affinity Photo
Affinity Photo has a tool called the “Luminosity Mask Creator” which can be used to create luminosity masks. To use the Luminosity Mask Creator, select the “Tools” menu and then choose “Luminosity Mask Creator.”
The Luminosity Mask Creator tool has two options: “Create Mask” and “Edit Mask.” The “Create Mask” option will create a new luminosity mask based on the brightness of the pixels in the image. The “Edit Mask” option will allow you to edit an existing luminosity mask.
To create a new luminosity mask, select the “Create Mask” option and then choose the “Brightness” option. This will create a mask that includes all the pixels in the image that are brighter than the selected brightness value.
Next, select the “Mask Type” option. There are three options for the mask type: “Selection,” “Layer,” and “Channel.” The “Selection” option will create a mask that can be used to make a selection in the image. The “Layer” option will create a new layer that contains only the pixels that are included in the mask. The “Channel” option will create a new channel that can be used to make a selection in the image.
Finally, select the “Output” option. This will determine how the luminosity mask is outputted. There are three options for the output: “Selection,” “Layer,” and “Channel.” The “Selection” option will output the luminosity mask as a selection in the image. The “Layer” option will output the luminosity mask as a new layer. The “Channel” option will output the luminosity mask as a new channel.
Once the options have been selected, click the “Create” button to create the luminosity mask.
How to Use a Luminosity Mask
Luminosity masks can be used to make precise selections in an image. For example, a luminosity mask can be used to select all the pixels in an image that are brighter than a certain value. This can be useful for making adjustments to only the bright pixels in an image, or for removing objects from an image that are brighter than the background.
To use a luminosity mask, select the “Select” menu and then choose “Luminosity Mask.” This will open the “Luminosity Mask” dialog.
In the “Luminosity Mask” dialog, select the luminosity mask that you want to use from the “Mask” drop-down menu.
Next, select the “Invert Mask” checkbox if you want to invert the luminosity mask. This will select all the pixels that are not included in the luminosity mask.
Finally, click the “OK” button to close the dialog and apply the luminosity mask.
Luminosity masks are a great way to make local adjustments to your photos without affecting the rest of the image. By isolating areas of brightness or darkness, you can selectively apply adjustments that would otherwise be difficult to target.
In Affinity Photo, there are two ways to create luminosity masks: through the Channels panel, or by using the Selection brush.
To create a luminosity mask through the Channels panel:
1. Open the Channels panel (Window > Channels).
2. Select the channel that contains the most contrast. This is typically the Red channel for landscapes, or the Blue channel for portraits.
3. Click the Create New Channel button at the bottom of the panel.
4. In the New Channel dialog, name the channel and click OK.
5. In the Layers panel, click the new channel to select it.
6. Press Cmd/Ctrl+A to select all, then Cmd/Ctrl+C to copy.
7. Switch back to the RGB channel and paste the copied channel (Cmd/Ctrl+V). This will create a new layer containing the luminosity mask.
8. In the Layers panel, change the layer blend mode to Luminosity.
9. Add a layer mask and use a black brush to paint over any areas that you don’t want to be affected by the luminosity mask.
To create a luminosity mask with the Selection brush:
1. Select the Selection brush from the toolbar.
2. In the brush settings, set the mode to Add and the strength to 100%.
3. Paint over the area of the image that you want to target with the luminosity mask.
4. In the Layers panel, click the Add Layer Mask button.
5. In the Add Layer Mask dialog, select Luminosity from the drop-down menu and click OK.
Now that you’ve created your luminosity mask, you can use it to make selective adjustments to the brightness or contrast of your image. Simply add a new adjustment layer (Layer > New Adjustment Layer) and clip it to the luminosity mask layer. Then, use the adjustment layer to target the areas of the image that you want to affect.
Now that you have your black and white image, it’s time to create your luminosity mask.
To do this, go to the “Select” menu and choose “Color Range”. In the “Select” drop-down menu, choose “Luminosity”. Then, click on the black and white image in the “Source” field and click “OK”.
You should now see a white mask over your black and white image. This is your luminosity mask.
Now that you have your luminosity mask, you can use it to make selections in your image. To do this, go to the “Select” menu and choose “Invert”. This will invert your selection so that you can select the areas of your image that you want to lighten or darken.
Then, go to the “Edit” menu and choose “Brightness/Contrast”. In the “Brightness” field, enter a positive number to lighten the selection, or a negative number to darken the selection. In the “Contrast” field, enter a positive number to increase the contrast, or a negative number to decrease the contrast.
Click “OK” when you’re done. You should now see your luminosity mask selection applied to your image.
