Building a flame mask

Our composition is looking pretty great with the exception of this flame, which…doesn't look right at all.…Now, the thing about a flame is that it naturally increases the brightness of…the background behind it.…So it's a kind of anti-shadow in other words, and just as you would generally…set a shadow to the Multiply mode, we should set a flame to the Screen mode and…that way instead of this opaque and fairly scrawny flame, we'll end up with…something more like this.…And so in this exercise we'll mask the flame and then in the next exercise…we'll composite it.…Now to mask the flame I need to reinstate an opaque version of it.…

So over here in the layers panel I'll Alt+Click in a horizontal line between…the top two layers, and then I'll Shift+Click on the layer mask thumbnail for that normal layer.…Now let's check out what we have to work within the Channels panel.…I'll switch over to it.…Here's the Red channel and you can see that the flame is very bright against a…fairly bright background as well.…