Photoshop tutorial 7

Easy Selections with Channels

Overview:

This tutorial will show you how to use Channels to create a Mask.

This method is best used for hard to select objects on high contrast backgrounds.

STEP 1: Open and Duplicate your image

File -->Open (Ctrl-O) Open your image.

Duplicate your background by dragging the ‘Background’ layer (in the layers palette) to the ‘Create new layer’ icon at the bottom of the ‘layers palette’.

STEP 2: Pick your best Channel

Open your ‘Channels’ palette (Windows --> Channels). With the palette open click on each RGB channel (Red, Green and Blue). Look for the channel with the most contrast between your object and the background. For this picture I choose Blue (Ctrl 3). We don’t want to destroy this channel so grab it and drag it down to the ‘Create New Channel’ button at the bottom of the ‘Channels’ palette. This will make a ‘Copy’ of the Blue channel for us to use for our mask.

STEP 3: Create more Contrast

For our Mask to work we need to get rid of all our Mid-tones. We want the final mask to be only black and white. To do this we need to start with a levels adjustment.

With your ‘Blue copy’ selected in the ‘Channels’ palette, open the ‘Levels’ dialog box (Image --> Adjustments --> Levels). In the ‘Input Levels’ area of the dialog box, drag the Black slider in until the darks are dark, real dark. As dark (Black) as you can get without losing edge detail. Now do the same with the ‘White’ slider. Click ‘OK’.

Notice below that I used the ‘Blue’ Channel. Not the ‘Blue Copy’. Oops. I had to go back and re-do it (Ctrl-Z, to undo).

STEP 4: Paint the Background

With the ‘Lasso’ tool selected (L), make a loose selection around the flower.

Now we have our flower selected, but we want the background selected instead. To do this hit Ctrl-Shift-I (Select --> Inverse).

We need the background solid black. So with our background now selected click ‘D’ to give us our Default Foreground/Background colors and ‘Backspace’. Everything in the selection should now be black. Ctrl-D, to de-select.

If you still have some lighter areas around the flower, choose your ‘Brush Tool’ (B) from the ‘Tools’ palette. In the ‘Options’ palette, select ‘Overlay’ from the ‘Mode’ drop down menu. With Black as your foreground color (‘D’ then ‘X’), start to paint around the flower. This will make the dark pixels darker but will not change the light pixels. You might have to go over some areas a few times. Now hit ‘X’ to make White the foreground color and paint on the flower. This will make all the lighter pixels white.

We need to get rid of the black center section now. Set White as your foreground, and in the ‘Options’ palette, set the ‘Mode’ back to normal. Now just paint the center white.

*Note*

At this point you might want to ‘Blur’ the edges of your selection. To do this you will need your mask selected in the Channels palette. Select the ‘Blur’ tool (R) from the ‘Tools’ palette, and just run around the edges of the mask.

STEP 5: Load mask as a Selection

To make our Mask a Selection, click on the ‘Load Channel as Selection’ button at the bottom of the Channels palette.

Select the ‘RGB’ channel (Ctrl ~), and hit Ctrl-J (Layer --> New --> Layer Via Copy) to create a new layer via our selection. We now have a selection of the flower on its own layer.

STEP 6: Add a new background.

With your “new” background open in another window (Ctrl-O), select the ‘Move Tool’ from the tools palette. Hold down the Shift key as you drag the ‘new background’ ONTOP of your flower selection. Holding down ‘shift’ will center your new layer.

Now for the magic. Grab and drag your new layer (Layer 2) down below ‘Layer 1’.

VOILA!

An even better way to do this is to drag ‘Layer 2’ below the ‘Background copy’ layer. Then with the ‘Blue copy’ channel selected (in the channels palette) click on the ‘Load Channel as Selection’ button at the bottom of the Channels palette. With your mask now selected, select the ‘Background copy’ layer in the ‘layers’ palette. Click on the ‘Add Layer Mask’ button on the bottom of the ‘layers’ palette and BOOM! You now have a “non-destructive” layer mask.