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

Selecting from a channel

From: Photoshop CC Selections and Layer Masking Workshop

Video: Selecting from a channel

You're probably already aware that the color information in our photos comes from individual channels. A typical image has a red, green, and blue channel, each of which indicate the intensity of red, green, or blue light that is reflected in each pixel. In other words, those channels define the actual color for each pixel in our images. But we can also use that information to create a selection. Let me show you how. We'll start off by going to the channels panel, if your Channels panel is invisible, you can choose it from the Window menu.

Selecting from a channel

You're probably already aware that the color information in our photos comes from individual channels. A typical image has a red, green, and blue channel, each of which indicate the intensity of red, green, or blue light that is reflected in each pixel. In other words, those channels define the actual color for each pixel in our images. But we can also use that information to create a selection. Let me show you how. We'll start off by going to the channels panel, if your Channels panel is invisible, you can choose it from the Window menu.

And then we're gong to click on each of the individual channels for this image. First, I'll click on the thumbnail for the red channel, so that I can take a look at that channel, and see if it might be a good candidate as a starting point for my selection. In this case, that's certainly not the case. I want to create a selection of this poppy including the stem. And you can see that on the red channel, parts of the poppy are very bright relative to the background and parts of the poppy, especially the stem, are very dark relative to the background. And that means we're not going to be easily isolate the poppy from the background using the red channel.

Next we'll take a look at the green channel, so I'll click on that thumbnail. And you can see that we have a better looking image. We have night contrast overall, but still not good contrast to separate the poppy from the background. When we take a look at the blue channel, however, we see a very good starting point. The poppy overall is very dark, and the background is very light. And that makes sense, of course, because the blue channel reflects the amount of blue light. The sky contains lots of blue, the poppy contains no blue or very little blue. And in fact, it contains the opposite of blue, lots of yellow. So the blue channel, in this case, is the best starting point. And actually you'll find that in many cases the blue channel is the best starting point for this technique, especially when a sky is involved. But for portraits, the red channel might work out better, and in some cases the green channel will work best.

You'll want to take a look at all three channels though to decide which one will give you the best starting point. Of course, the blue channel provides a great starting point, but not a final result. So, we're going to need to apply some adjustments here in order to enhance the contrast that already exists. Of course, I don't want to modify my blue channel directly, because that would affect the color in my image. And so instead, I'm going to drag the thumbnail For that blue channel, down to the blank sheet of paper icon, that create new channel button, at the bottom of the channels panel. And that will produce a blue copy layer.

Now, I can apply changes directly to this blue copy because it is an alpha channel. It's an extra channel you might say. Not one of the red, green, or blue channels that define the color in my image. Image. So to adjust that channel, I'll go to the Image menu and choose Adjustments followed by Levels, and then I'll drag the black point inward to darken the poppy, and the white point inward in order to brighten the sky, and ultimately I want to try and bring them all the way right next to each other, so that I end up with a really good selection here.

Well it's not a selection yet but it will be shortly but I want to have that silhouette effect. I want the poppy to be entirely completely black and the sky to be entirely completely white. And with this level's adjustment that appears to be the case so I will go ahead and click okay. In order to apply that change, but now I notice there's a little bit of a problem. Up toward the top right, you'll see that the entire sky did not go white, and I have some black areas up there. Now, you might assume that I would want to modify that levels adjustment in order to get those areas white, but in this case, that simply wasn't going to work.

If I applied a different adjustment, sure, I might get those areas to be white, but I would also cause some problems for the poppy. The form, here, would no longer match the exact edges of the poppy. So instead, I'll use a slight variation, here. I'll just choose the Brush tool from the toolbox. And then I'll press the letter D on the keyboard to make sure my colors are set to the default values. Which, in the case of a channel is white for the foreground and black for the background. I can then move my mouse out over the image and adjust the brush size as needed, using the Left Square Bracket key to reduce the brush size.

And the right square bracket key to increase the brush size. I'll also make sure that the blend mode on the options bar is set to normal and that I'm working at a 100. Percent opacity for my Brush tool. And then, with white as my foreground color, I can press X as needed to switch foreground and background colors. I'll simply click and paint over those areas in order to effectively erase those black spots in the sky, replacing them with white. (SOUND) And of course I could also paint with black in the poppy if I needed to tune any areas, but at this point I think I'm in good shape. I have a black poppy set against a white sky and that is a great basis for selection.

So at the bottom of the channels panel, all I need to do is click on the load channel as selection button. That dash circle icon. And that will create a selection where all white areas of this alpha channel are selected, and all black areas are deselected. And any shades of gray would be partially selected. So at this point I have my selection created. I can click on my color tile, the RGB tile, to get back to my full image. And as needed, I could also invert the selection. In this case, I do want the opposite selection because I actually wanted the poppy to be selected. So I'll go to the Select menu and choose Inverse, and now I have the opposite selection, although I'm also noticing that there are still a couple of problems up at the top left.

So I missed a couple of those specks on that blue copy channel, but that's okay. I can still modify the result. Even though I didn't use a selection tool to create my selection. I can use additional selection tools to modify that selection. So, for example, in this case, I can choose the Lasso tool from the toolbox, and then hold the Alt key on Windows or the Option on Macintosh in order to access the Subtract From Selection option. And then I can just draw a lazy loop around that area where I have a couple of pixels that were still selected. And that will remove those pixels from the selection.

So I can utilize one of the channels as the basis of a great selection but then fine tune my results as needed in order to get the best selection possible.

Show transcript

This video is part of

Image for Photoshop CC Selections and Layer Masking Workshop
Photoshop CC Selections and Layer Masking Workshop

51 video lessons · 10668 viewers

Tim Grey
Author

 
Expand all | Collapse all
  1. 1m 27s
    1. Welcome
      1m 27s
  2. 46m 26s
    1. Selections, alpha channels, and layer masks, oh my!
      5m 48s
    2. Anti-aliasing and selections
      6m 6s
    3. The case for not feathering selections
      6m 50s
    4. Adding, subtracting, and intersecting
      7m 31s
    5. Inverting a selection
      3m 4s
    6. Mixing and matching selection tools
      2m 32s
    7. Using Deselect and Reselect
      3m 47s
    8. Temporarily hiding a selection
      2m 7s
    9. Saving and loading selections
      6m 14s
    10. Using the cursor for selections
      2m 27s
  3. 51m 42s
    1. The Rectangular Marquee tool
      8m 24s
    2. The Elliptical Marquee tool
      6m 2s
    3. The Lasso tool
      4m 55s
    4. The Polygonal Lasso tool
      6m 27s
    5. The Magnetic Lasso tool
      10m 9s
    6. The Quick Selection tool
      5m 33s
    7. The Magic Wand tool
      10m 12s
  4. 38m 38s
    1. Selecting the border of an existing selection
      1m 50s
    2. The Color Range command
      7m 19s
    3. Focusing a Color Range selection
      2m 55s
    4. Selecting faces with Color Range
      2m 31s
    5. The Pen tool
      5m 40s
    6. Selecting by luminosity
      3m 39s
    7. Selecting from a channel
      6m 13s
    8. Transforming a selection
      4m 4s
    9. Quick Mask mode
      4m 27s
  5. 50m 46s
    1. Combining layers into a single document
      1m 49s
    2. Layering images manually
      1m 55s
    3. Assembling a panorama automatically
      3m 1s
    4. Advanced blending
      4m 0s
    5. Painting to hide and reveal
      3m 24s
    6. Creating a selection-based composite
      2m 43s
    7. Select, then paint
      3m 28s
    8. Advanced mask cleanup
      6m 18s
    9. Creating an edge-fade effect
      2m 23s
    10. Using a filter to add an artistic edge
      3m 6s
    11. Using a brush effect to add an artistic edge
      5m 30s
    12. Transforming a masked object
      1m 51s
    13. Unlinking image and mask
      2m 53s
    14. Matching composite images
      2m 17s
    15. Adding layer effects with masks
      2m 21s
    16. Reviewing layer masks
      3m 47s
  6. 28m 58s
    1. Painting in an adjustment
      3m 20s
    2. Shades of gray
      3m 14s
    3. Using the Gradient tool
      4m 4s
    4. Adjusting a selected area
      1m 42s
    5. Creating a vignette effect with masking
      2m 13s
    6. Using a layer group
      3m 34s
    7. Working with multiple masks
      4m 5s
    8. Refining an adjustment mask
      6m 46s

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 CC Selections and Layer Masking 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 preferencesfrom 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.