Title:Using Channels to make Selections Software:Photoshop Author:spdfreak_95 Description:(Please read the following)
Selections can be made using a variety of different methods. But you first need to take a look at the image you are working with, and decide which method would be BEST suited for its intended result. For me (and I’m sure everyone else would take the same approach), I would ordinarily opt to do the fastest/easiest method i.e. the Magic Wand Tool. We know this tool is good when there is a high degree of contrast between the intended selection area and the background; but 99.9% of the time this is not always the case. So we find ourselves slowly making our way through the other methods we may have learnt. These methods may include but are not limited to, the Extract Filter, the Magnetic Lasso Tool to maybe the masking method. And in some cases using the technique described in the following tutorial……” Using Channels to make Selections”. This method is often used when other methods have not given us the results we were expecting. I’m not saying this is the “Be all to end all” in method types for making selections. It’s just another method that can be added to your arsenal of techniques for making selections. In saying that however, this method is used where there are a lot of fine edges i.e. hair, fur, grass, leaves on trees etc. and the results obtained from using this method will yield far better results than any other. The tutorial may look/sound complex at a glance, but in actual fact it’s easy and not a long process at all, and some amazing results can be had by using this technique. What is hard however, is making the best adjustments possible in the Levels Options (Step Four)
Open a RGB image (or convert your image to RGB... (Go to>Image>Mode>RGB)).
Go to the Channels Palette.(There should be a Tab next to the Layers Tab called Channels). If not, go to Windows>Channels.
You now need to decide which Channel Colour (Red, Green or Blue) will give you the best starting point for making a black and white mask. Toggle through each colour and select the colour with the best contrast. For this tutorial Green was the best option.
Here’s the result I got for step two
Duplicate the channel by dragging the Green Channel down to the New Channel icon (as indicated by the arrow in the image below). Make sure its active (i.e. the one you are working on).
Go to>Image>Adjustments>Levels (Ctrl+L)
Now move the left and right sliders towards the centre (as illustrated below) to make your channels’ light areas lighter and the darker areas darker….
Basically, what we are trying to do here is give the best contrast of black and white over the entire image. (Make sure you focus on what you want to be selected…. (the hair) These are the areas where you want the contrast most to take place…. Don’t worry about the other areas at this stage). Once you are happy with the contrast obtained click OK.
NOTE: (It’s not going to be perfect, but we want it to be as close to black and white as possible)
Here are the settings I have used for this example (They will vary from image to image).
Here is the result I got for Step Four
Make sure you have your Foreground and Background colours set at default (Black and White), and start to paint with the Brush Tool all the light areas with white and the darker areas with black You need to make sure that all of the black area (circled in image below), is completely filled i.e. the small white dots and the dogs’ nose etc, because this is the area that will “end up” being our selection and any white dots left inside the black mask will not be selected (i.e. appear transparent)
Here is the result I got for Step Five
At this stage it is a good idea to give the channel a Gaussian Blur of 0.5-1.0 pixel. (Go to>Filter>Blur>Gaussian Blur). I used a Radius of 1.0 This will eliminate some of the hard jiggered edges
Load the channel as a selection (Ctrl+clicking the Alpha Channel). Next, Go to Selections>Inverse (Ctrl+I) While still in the Channels Palette, click on the RGB Channel (to make active). All the other channels should now be visible Go back to the Layers Palette by clicking the layers Tab
Select the Background Layer (original image) Go to Edit>Copy (Ctrl+C) Go to Edit>Paste (Ctrl+V) Your selection of the image should now be on its own layer.
Here is the final result that I got with a gradient background and a drop shadow added. It has a sound for those curious
