Painting in the missing details

In this exercise we're going to go ahead and mask in the missing details, which…in our case includes the rim around the mask, as well as the snorkel tube.…And these are the kinds of details that aren't necessarily going to be…automatically accounted for by the Calculations command or Apply Image for…that matter, so we are going to take advantage of the automated selection…functions inside Photoshop.…I've gone ahead and saved my progress as Blue screen mask.psd, found inside the…01_calculations folder and I am going to switch back to the RGB composite image.…Now there is couple of ways that we might select these items.…

One is we can go up to the Select menu and choose the Color Range command.…Because after all, the snorkel tube is fairly uniformly white and the rim around…the mask is uniformly blue.…However, color range isn't going to work too well, because after all we've got…all kinds of other blues associated with the background and we are going to end…up picking them up with this command.…