We launched a new IT training category! Check out the 140+ courses now.

Easy-to-follow video tutorials help you learn software, creative, and business skills.Become a member

Selecting from a channel

From: Photoshop Selections Workshop

Video: Selecting from a channel

In this lesson I'm going to show you one of my all time favorite techniques for creating a selection in Photoshop. This method makes use of a color channel as the basis of a selection. Let's take a look at how it's done. The first thing we need to do is to evaluate the individual color channels for the image. So, I'll go to the Channels panel and then click on each of the thumbnails for the red, green and blue channels in turn. What we're looking for is good contrast in the area that we want to select.

Selecting from a channel

In this lesson I'm going to show you one of my all time favorite techniques for creating a selection in Photoshop. This method makes use of a color channel as the basis of a selection. Let's take a look at how it's done. The first thing we need to do is to evaluate the individual color channels for the image. So, I'll go to the Channels panel and then click on each of the thumbnails for the red, green and blue channels in turn. What we're looking for is good contrast in the area that we want to select.

In this case, I'd like to make a selection of the poppy. And so, I'm looking for good contrast between the poppy and the sky. Here you can see we have some good contrast for example the flower petal up here at the top has pretty good contrast relative to the sky but down below there's not as much contrast. Taking look at the green channel you can see we have an image that seems to represent a better starting point as a black and white imae But we do have the same problem where portions of the pedals blend very smoothly into the sky. Taking a look at the blue channel, you can see we have great contrast between the Poppy and the sky.

As a result the blue channel is the best starting point for this particular image. In fact that's why I chose this image to demonstrate the technique but I assure you that in many situations even when you don't think it's going to be possible to make a selection this technique can work really well. All you need is a little bit of color contrast. There doesn't even need to be very obvious luminance contrast between the area you want to select and other areas of the image. Since we've identified the blue channel as the best starting point, I'm going to make a copy of the blue channel. If I were to work directly on a color channel, I'd be altering the color appearance of the image, and I most certainly don't want to do that. So I'll drag the thumbnail from my blue channel down to the Create New Channel button, the blank sheet of paper icon at the bottom of the Channels panel. This will create a blue copy channel which is an alpha channel. In other words not a color bearing channel.

It's not one of the red, green or blue channels that determines the color of pixels within the image. I can therefore work directly on this blue copy channel being as destructive as I want knowing it's not going to actually effect the appearance of the image. Now this channel represents good contrast between the poppy and the sky. But I need great contrast so I'm going to choose image adjustments levels from the menu in order to apply a levels adjustment directly to this blue copy channel.

I'll bring the white point inward in order to turn the sky completely white, and I'll bring the black point inward in order to make the poppy completely black. I can also adjust the mid point of the slider as needed. Basically what I want to accomplish is squeeze both of these sliders, the black and white sliders together, so that they are compressed and every pixel in this channel is either pure black or pure white. As you can see, that creates a great silhouette so I've now defined a good outline for my poppy. I'll go ahead and click okay to apply that levels adjustment. Of course in this case I have some problem areas up in the corners of the image.

Perhaps if I had adjusted the sliders in the levels dialog a little more carefully, I might have been able to avoid that. But the important thing, is that we can very easily clean this up. I'll simply choose the brush tool, and then make sure I'm working with white as my foreground color, and then simply paint to clean up these areas. In this case I'll press the right square bracket key to increase the size of my brush, so I can work a little more quickly. And there we go. All of those areas are cleaned up. Similarly if there were some specs inside the poppy, I could switch my foreground color to black and then paint over those areas.

At this point, I have a great silhouette for my poppy so I'm ready to create a selection. All I need to do is to click the load channel as selection button, the dashed circle icon at the bottom of the channels panel. This will cause white areas to be selected, and black areas to be deselected. This happens to be the opposite of what I want, and so I'll choose Select > Inverse, from the menu, in order to get the opposite selection. In this case the selection of the poppy. I'll go ahead and click on the RGB tile, so that we can get back to the full color image, and as you can see we've got a great selection. The individual color channels that make up the full color information in an image often contain unique contrast that can be put to use to create a selection for what might otherwise be a tricky situation.

As a result, using a channel as the basis of a selection is the selection technique I use most often in Photoshop.

Show transcript

This video is part of

Image for Photoshop Selections Workshop
Photoshop Selections Workshop

31 video lessons · 2065 viewers

Tim Grey
Author

 

Start learning today

Get unlimited access to all courses for just $25/month.

Become a member
Sometimes @lynda teaches me how to use a program and sometimes Lynda.com changes my life forever. @JosefShutter
@lynda lynda.com is an absolute life saver when it comes to learning todays software. Definitely recommend it! #higherlearning @Michael_Caraway
@lynda The best thing online! Your database of courses is great! To the mark and very helpful. Thanks! @ru22more
Got to create something yesterday I never thought I could do. #thanks @lynda @Ngventurella
I really do love @lynda as a learning platform. Never stop learning and developing, it’s probably our greatest gift as a species! @soundslikedavid
@lynda just subscribed to lynda.com all I can say its brilliant join now trust me @ButchSamurai
@lynda is an awesome resource. The membership is priceless if you take advantage of it. @diabetic_techie
One of the best decision I made this year. Buy a 1yr subscription to @lynda @cybercaptive
guys lynda.com (@lynda) is the best. So far I’ve learned Java, principles of OO programming, and now learning about MS project @lucasmitchell
Signed back up to @lynda dot com. I’ve missed it!! Proper geeking out right now! #timetolearn #geek @JayGodbold
Share a link to this course

What are exercise files?

Exercise files are the same files the author uses in the course. Save time by downloading the author's files instead of setting up your own files, and learn by following along with the instructor.

Can I take this course without the exercise files?

Yes! If you decide you would like the exercise files later, you can upgrade to a premium account any time.

Become a member Download sample files See plans and pricing

Please wait... please wait ...
Upgrade to get access to exercise files.

Exercise files video

How to use exercise files.

Learn by watching, listening, and doing, Exercise files are the same files the author uses in the course, so you can download them and follow along Premium memberships include access to all exercise files in the library.


Exercise files

Exercise files video

How to use exercise files.

For additional information on downloading and using exercise files, watch our instructional video or read the instructions in the FAQ .

This course includes free exercise files, so you can practice while you watch the course. To access all the exercise files in our library, become a Premium Member.

Join now Already a member? Log in

Are you sure you want to mark all the videos in this course as unwatched?

This will not affect your course history, your reports, or your certificates of completion for this course.


Mark all as unwatched Cancel

Congratulations

You have completed Photoshop Selections Workshop.

Return to your organization's learning portal to continue training, or close this page.


OK
Become a member to add this course to a playlist

Join today and get unlimited access to the entire library of video courses—and create as many playlists as you like.

Get started

Already a member ?

Become a member to like this course.

Join today and get unlimited access to the entire library of video courses.

Get started

Already a member?

Exercise files

Learn by watching, listening, and doing! Exercise files are the same files the author uses in the course, so you can download them and follow along. Exercise files are available with all Premium memberships. Learn more

Get started

Already a Premium member?

Exercise files video

How to use exercise files.

Ask a question

Thanks for contacting us.
You’ll hear from our Customer Service team within 24 hours.

Please enter the text shown below:

The classic layout automatically defaults to the latest Flash Player.

To choose a different player, hold the cursor over your name at the top right of any lynda.com page and choose Site preferences from the dropdown menu.

Continue to classic layout Stay on new layout
Exercise files

Access exercise files from a button right under the course name.

Mark videos as unwatched

Remove icons showing you already watched videos if you want to start over.

Control your viewing experience

Make the video wide, narrow, full-screen, or pop the player out of the page into its own window.

Interactive transcripts

Click on text in the transcript to jump to that spot in the video. As the video plays, the relevant spot in the transcript will be highlighted.

Are you sure you want to delete this note?

No

Your file was successfully uploaded.

Thanks for signing up.

We’ll send you a confirmation email shortly.


Sign up and receive emails about lynda.com and our online training library:

Here’s our privacy policy with more details about how we handle your information.

Keep up with news, tips, and latest courses with emails from lynda.com.

Sign up and receive emails about lynda.com and our online training library:

Here’s our privacy policy with more details about how we handle your information.

   
submit Lightbox submit clicked
Terms and conditions of use

We've updated our terms and conditions (now called terms of service).Go
Review and accept our updated terms of service.