Richard O'Brien | 14 August 2014
Q&A on some basics of Photoshop layer masks
Just having come back from a week away from work with my kids, I felt I had to write this short post following on from a question that my daughter - who's studying photography - asked me last week.
"Dad, can you show me how to do layer masks properly [in Photoshop]?"
It transpires that as part of her photography course at college, she's expected to use Photoshop but sometimes the information they're given is too brief (either that or she's not listening!).
So, I thought I'd put together a quick Q&A on some basics of layer masks.
Q:What is a layer mask?
A: A layer mask hides, or masks to content of a layer, thus revealing the contents of the layer beneath it
Q:How do I create one?
A: Select the layer that needs to be masked and click the 'Add a mask' icon at the bottom of the Layers panel. Alternatively, if you add an adjustment layer it automatically comes with its own layer mask.
Q:How does it work?
A: To the right of the layer will be another icon - the layer mask. You paint on the mask using a regular brush. Anywhere you paint in black will be hidden (masked out), anywhere you paint in white will be visible. As someone far wiser than me once said "black to conceal, white to reveal". Here a layer mask has been used to hide the sky in the layer.
Q:Why use them?
A: Simply, they're non-destructive. No pixels have been deleted, just hidden. Thus by painting in white they can be revealed if necessary. This makes editing image very flexible indeed.
Q:Anything else I should know?
A: Lots! But two very simple tricks - hold SHIFT and click on the layer mask thumbnail to disable/enable it, hold ALT (Mac: Option) and click on the layer mask thumbnail to show the mask in the main window/revert to normal display, and lastly painting in shades of grey to hide some of the layer allows you to control opacity (kind of) for individual parts of the layer.
And there you have it - a quick lesson in layer masks. And in the time it took me to write this post, my daughter went from not really understanding masks to being fully conversant with the basics of how they work and how to use them!