PSC 18: Quick Mask

One of my frequently used tools in Photoshop is the quick mask. It's a very visual way to edit selections on pictures, and by using it, you can easily do a few things that are much harder to do with other methods.

Let's for example take the image of my eye that I used as the cover image for tips from the top floor #145

Not a very special picture, just a close-up of an eye. My idea was to make something special out of this, and as I've recently seen a similar picture of Al Gore on the cover of the May issue of the Wired magazine, where he had incredibly blue eyes, I thought why not give this a try with one of my own pictures and see if I can recreate a similar effect.

The Quick Trick

Now what something like this usually involves in Photoshop is to do very selective changes that only apply to parts of the image, and if you have closely followed the previous episodes of Photoshop Corner, you know that we use masks to do this.

To mask an irregular shape, such as the iris of an eye, the quick mask tool does the trick quickly and with ease. Just hit the Q key and you're in quick mask mode. You can now paint your selection onto the picture with a black brush. In the case of our eye picture, I used a brush with a soft edge, to make the selection feather into the surroundings.

Red-Eye

"But why is it painting red?" I hear you ask. Well, the red colour is a visual representation of your selection. It's not actually painting the colour red. Once you are finished painting your selection, just hit the Q key again and you're back in selection mode. And there you go: you have painted a selection. The areas that you painted on are unselected, and everything else in the picture is selected.

Marching Ants

This is almost what we're looking fore, but not quite. So let's invert the selection by going to the menu and choosing Select / Inverse. Now the pupil is selected in the picture. And even though the selection is showing you a hard boundary in this view, the actual selection is feathered, just as you painted it.

Blue Magic

And now comes the neat part. Let's click the half-black half-white circle at the bottom of our layers palette and bring up a Hue/Saturation layer. As we had a selection to start with, the Hue/Saturation layer automatically picked up the selection and transformed it into a mask. So all the operations that we now do on that layer will only affect the selected iris.

Slide the Hue slider back and forth a bit and see how the colour of the iris changes. Neat, isn't it? 

Plain Old S-Curve

The next step I did in that picture was to apply an overall curves layer to increase the contrast a bit with an S-curve. Nothing spectacular there, I just wanted to give the image a bit more pop this way.

Same Old Selection

But I'm still missing a bit more brightness in the blue eye, so what I want to do is to apply another curves layer, but to the same selection that I had before. Now I didn't save the selection, but here's a trick that lets you recover that exact same selection easily. Go to the layer palette and CTRL/Option-click the mask that is attached to the Hue/Saturation layer that we created earlier.

This will bring back the selection, and now it's just a matter of adding another curves layer, which will also automatically pick up that selection as a mask, and this way apply some midtone adjustments to bring up the brightness of the iris separately from the rest of the picture.

Take A Sharp Look

And the last step in the process as usual is the sharpening. And in addition to applying some regular Unsharp Mask, I also selected the sharpening tool from the tool palette, and applied some additional sharpening to the iris by simply painting over it with the sharpening brush.