Use Channels to Create Selections


Adobe® Photoshop® Intensive


Lesson Info

Use Channels to Create Selections

So I'm gonna go ahead and open up a photo here and working in a folder number five if you've purchased the course, she did get access to the exercise files, so we're in day two of folder number five channel selections in here again, I've given you my original files as well as a psd so you can reverse engineer this stuff, so we're going to go ahead and pop open this photo, and if you look in the layers panel to see what we have going on here, we've got sand on one layer and we've got a very wispy, finally translucent flower on the other layer, and then we've got a mask a regular pixel mass. We know it's a regular pixel mass because it's black, not gray we could paint on this mass to fine tune it if we needed tio, so I've used the mask to hide the sky so that the flower shows through on the sand, so I'm gonna go ahead close that we'll start with the original flower photo and see how we can make that happen. So go ahead and open both the flower and the sand photos and click the tab of the...

flower photo so if our job was to mask the sky in this photo let's run through our selection tools again that we've used so far are the selection mark he's going to help us new p r the lasso tool is going to help us know are the color selection tools going to help us? Not really, because this flower is slightly translucent, so it would be quite difficult and time consuming to try to get a good selection around it based on color, you have yet another option. Oh, let's, go him. Look at the vector tools. Are any of the vector tools going to help us? No, what can we do? Well, you can use something called channels to create a selection. So let me show you the channel's panel because we haven't seen that quite yet. It's already open on my system over here on the right, so I'm in a single click its tab to show it to you. If it's not open on your system, go to the window menu and choose channels. And here again, I want to make the this icahn larger so we can actually see it. So I'm going to open up the channel panel options by clicking the little fly out menu to the top right of the channel's panel. And when you do slide down to the bottom and choose panel options, and then you want to click on that large thumbnail. And when I click ok, watch over here in my channels pain all you're going to see all those thumbnails get actually big enough to see so this data that you're seeing right here try to zoom in a little bit here what you're seeing in this panel is thie information that was captured from your camera split out among three different colors okay, so this one right here is showing you all of the different colors the three colors smashed together soon back out if we were to turn the visibility I off on this rgb channel nothing happens I'm going to use my keyboard shortcuts okay, the keyboard shortcuts for going through these channels are over here on the right hand side okay, so commander control two three four five we'll let you cycle through the channels the reason it's not letting me turn that office because it has to have one of them on so I'm gonna go ahead and press a commander control three, four, five and that's not letting me see them either. Okay, we're going to go back over here to the layers panel because I know it'll work there. Okay, I'm gonna go through my little why is that not working? That is so interesting stand by houston we're experiencing technical difficulties, okay? Maybe because I was on the red channel now let's give a shot there we go. All right, I had activated one of those other channels and it was confusing photo shop so here we are now you can see this information is what was captured by the red sensors in your cameras. Your camera has three different color sensors that it can pick up it's really picking up brightness levels or gray scale values in three different color groups. Okay, so your camera has red sensors, green sensors in blue sensors. Okay? And this is the information that was picked up by the red sensor. If I press command or control four, which is the keyboard shortcut for the green channel, then you're going to see the information that was captured on the green sensors in your camera. If I press commander control five, you're going to see the information that was captured on the blue sensors. Okay, so you're all images were composed of three different colors red, green and blue and from those colors come all the rest, the colors. Ok, those are our primary colors to use channels as a method of getting a selection of an item. You want to find the channel where the item you want to select is the darkest okay, so if we cycle back through our channels again by pressing commander control three four five our daisy, which is what we want to select is the darkest in the blue channel and I will tell you up front that this is a bit of a complicated technique, but we're going to go through it three or four times, so just hang in there with me so our first goal is to find the channel in which the item iwant to select is the darkest well that will most ofthe sometimes be the blue channel so sure enough, we look in our channels panel here we've landed on the blue channel and you don't even have to be in the channels panel to do this if I go back to my layers panel and I pressed my commander control three, four, five I'm still cycling through channels, ok, but she didn't want to take a peek in your channels panel to see which one you landed on stop on the one where the item is the darkest. Now what we're going to do is we're going to use an adjustment tool to force that flower to be solid black and we're going to use the same tool to force this background to solid white if we can make that flower solid black and the background solid white weaken load that channel as a selection and our mask will be perfect no tweaking, no fine tuning perfect so but because we don't want to mess up our original image, we don't want to be dinking around with the information in that blue channel so we can make a copy of it then we can mess around with the copy that we can men turn off and not even care if it's hanging around in our channels panel so to make a copy we're going to click and drag the channel thumbnail okay so click and drag the picture part down onto the new channel icon at the bottom of the channel's panel which looks exactly like the new layer icon in the layers panel it's a piece of paper with a folded corner soon as you do that we get a new channel called blue copy and that's what we want now the easiest way to make our flower solid black and our background solid white is to open what's called a levels layer or levels adjustment rather and levels of something that we're going to dive headfirst into tomorrow when we get into retouching and but for right now you can think of a levels adjustment as yours you use it to tell photoshopped what really should be black and what really should be white so we're going to open it up and we're going to tell photo shop a photoshopped make this daisy black and they were going to say yeah make this background white so we're gonna cruise up to the image menu choose adjustments levels or if your family keyboard chart tests press command ale or control ellen a pc this adjustment gets its name from adjusting the levels of brightness in your image that's where the levels name comes from because you're really using it to adjust brightness what we're seeing here in the levels adjustment dialogue is a history graham, which is a syriza of really, really tiny bar graphs that represent the various different levels of brightness contained in your image. Simon is a man, so you can see this a little bit better the left end of the history ma'am deals with shadows and miriam into the darkest parts of your image the right into the history and deals with the highlights or the lightest parts of your image, you'll notice that these little triangular sliders underneath the hist agrium are also filled with a color the highlight sliders filled with why so we can use that till photo shop what should be? Why in her image the shadows sliders feel with black so we can use that to tell photo shop what really should be black in our image so I'm gonna go ahead and zoom back out if you take that shadow slider and you start dragging it rightward that daisy or flower, whatever it is will eventually become solid black, which is what we want, so I just had to drag the shadow slider a little bit to the right and again we're going to be going through this at least three more times now my flowers looking good, but my background has darkened as well. Well, that's, easily fixable over here toward the right side of the dialogue. You have a serious of eye droppers you can use thes hotel photo shop what really should be wider black. Okay, so in this instance, it's easier to use this little white eyedropper here, see how they're filled with different colors that once filled with black that was filled with gray and this one's filled with why? Well, I'm going to click the white eye dropper, and I'm going to come over to a portion of my image that I want to be white, so if I start clicking around on this gray area, put a shop is gonna make it white, and I'm gonna move that out of the way and I'm simply kept clicking with the white eye dropper until photoshopped turned everything. Why? And again, you're just using that why eyedropper, you're telling photoshopped yeah, that gray stuff over there make it white that's all we did with that white eyedropper. So now that our daisy or whatever flower it is, is perfectly black and our background is perfectly white, we can now use thie load channel as a selection button that lives at the very bottom of the channel's panel it looks like a dotted circle. It's the left most button at the very bottom of that panel if you click, that photo shop is going to put the selection, marching and all the way around the background, which is the opposite of what we want. So in this situation we do. We can either flip the selection now are used the invert button in the masks panel like we've been doing six and one hand half dozen of the other, if you remember to do here great, if you know and you get back to your layers, pain on you add a mask and it does the opposite of what you want. You can always flip it there, but we'll go ahead and flip it here, so go ahead and go up to this select menu in choose inverse when I do that, notice how the marching ants around the screen or going to disappear now my marching answer going around on lee the flowers that means the flower is selected, not the background. Now I'm gonna go ahead and click back on my rgb channel, my master channel that shows all of the information from all three color channels mashed together and it looks like flower again. And isn't that a pretty dadgum accurate selection of said flower, so now we can go back to our layers panel? All we have left to do is add a mask, so we're gonna double click this layer to make it editable, and then we're gonna add our mask by clicking the circle within a square icon at the bottom of the layers panel and we have an absolutely perfect mask, so now we can add the sand or a different background. Whatever background you want, I clicked the arrange documents tab. Click to up and now I'll bring the focus onto the sand document so I can see it's layer and I can drag that I can either drag the sand over to the flower, or how about I destroyed the flower to sand. Here we go, close this guy, don't save, and I use my move tool to position the flower on top of our sand, and I'm going to zoom in, does so. You can see how miraculous that was. There's no edge halo there's, no blue left anywhere in that flour, so channels can be an incredibly powerful selection tool. But as you can see, it does take several steps.

Class Description

In this special photoshop tutorial, you'll dig into Adobe® Photoshop® CS5 with Lesa Snider, author of Photoshop® CS5: The Missing Manual. There is so much to cover in Adobe® Photoshop® CS5 that we need almost a week to cover everything. In this special 4-day workshop you'll dig into Adobe® Photoshop® CS5 with Lesa Snider, internationally acclaimed instructor and author. Lesa is informative yet entertaining with a unique way of explaining difficult concepts so you understand the "why" behind the "how". Get ready to spend a fun, high-energy week digging into the power of Photoshop.

Software Used: Adobe Photoshop CS 5.1


1Introduction: Nitty Gritty Basics + Layers 2Workspace Overview 3Q&A: Workspace 4The Truth About Resolution and File Formats 5Changing Resolution Without Changing Quality 6Q&A: Resolution and File Formats 7Resizing with the Crop Tool 8Cropping with the Ruler Tool 9Resizing with Content-Aware Scale 10Resizing for Print/Web 11Layers and Layer Types 12Duplicating, Moving, and and Aligning Layers 13Q&A: Layers 14Creating Reflections 15Layer Alignment Tools 16Simple Slimming Technique (Resizing Layers) 17Colorizing a Black and White Image 18Creating a Solid Color Fade with Fill Layers 19Layer Masks: Hand Painted Image Collage 20Layer Masks: Gradient Mask Collage 21Layer Blend Mode Collage (Include Load Images as Stack) 1Using Selections Part 1 2Using Selections Part 2 3Q&A: Selection Tools 4Color Selections: Fixing Animal White Eyes 5Tightening Up Layer Masks 6Painting Selections with QuickMasks 7Using Vector Drawing Tools 8Vector Shapes: Creating an Oval Vignette 9Vector Shapes: Rounded Edges to Photo 10Use Channels to Create Selections 11Tough Selections Around Hair & Fur 12Refine Edges Part 1 13Refine Edges Part 2 14Creative Edges on Photos 15Embellishing with Vector Art 16Creative Vector Photo Frames 17Editing Smart Objects 18Smart Objects Template: Creating Dark Edge Vignette 1Smart Objects: Selective Blurring 2Smart Objects: Selective Sharpening 3Sharpening with the High Pass Filter 4Q&A: Sharpening 5Auto Color Adjustments 6Shadows and Highlights 7Using Levels 8When to Use Smart Objects 9Using Curves 10Lightening and Darkening with Blend Modes 11Enhancing Eyes and Teeth 12Changing Colors with Hue/Saturation 13Changing Colors by Hand Painting 14Faux Dodge/Burn: Reduce Wrinkle 15Color to Black and White 1Healing Brush 2Content Aware Fill 3Using Text in Photoshop 4Designing with Baseline Shift 5OpenType Fonts 6Placing Text Behind an Object 7Barely There Text: Faded and Hollow Text 8Pushing Photos Through Text 9Adding Texture to Your Text 10Convert Text to Paths 11Combine Images using Advanced Blending 12Realistic Photo Aging 13Faking HDR 14Wrapping Texture Around an Object