Start learning with our library of video tutorials taught by experts. Get started
Viewed by members. in countries. members currently watching.
Take a 10-minute recess every week and join Bert Monroy in Adobe Photoshop or Illustrator, the playgrounds of digital artists. Every Friday Bert walks through a fun, self-contained project that tests your skills and challenges the imagination. These programs aren't just image editors; they are sandboxes for creativity and experimentation. Take a spin through a carousel of tools and get reinspired, each and every week.
Today we're going to look at an often overlooked feature of Photoshop, the Alpha Channel. Now on the screen right now, we have this big red ring. It's easy to make it look three-dimensional by lighting it in a certain way. What I'm going to do is go to that layer of the ring and I'm going to double- click on it to bring up the Layer Styles. I'm getting a little bevel and emboss. The light coming from the upper right there. Let's have it coming from right above. A little closer to the top there, like that. Increase the size a bit, make it a little softer, and maybe make the highlights a little stronger, right there like that.
Click OK, and there's a nice three dimensional ring. It's picking up the light sources making it look like it's rounded and so on. But what if we introduce another light source? Well, unfortunately you can only have one set of bevel and emboss, so we can't add another one to take into account this light here. And also the fact that this light is so close to the ring means that it's going to be really strong here and not as strong on this side. So what we need to do is to actually paint these highlights in and to do that we going to use a specialized mask and that is what's called the Alpha Channel.
So look at our channels here, and we have our basic channels. We have our red, our green, and our blue, which have the information for each of those colors. The Alpha Channels are additional channels that are not part of the image, but are simply ways in which you mask certain parts of the image in order to be able to work on those areas exclusively. So now, what I'm going to do is, I'm going to turn that ring into a selection, and I'm going to go ahead and save the selection. Under Select here we have Save Selection. I'm going to call this Ring.
Click OK, and when we look at our channels, there it is. We now have a new one, and you notice it's turned off because it's not part of the image. If you want to see it, there it is. It's showing up like a quick mask in red. All right, so there it is. So, I'm going to go in there and save it again. I'm going to save a second selection. And this one we're going to call, Edge. Now, why two? Let's deselect that. And the reason for two is you see what's happening here is, it's nice and hard along the edge, and then as it goes around that curve of the object, it starts to soften.
And that's what that second one is going to be. It's going to give us that softening effect. So let's go and look at these two. We see the red, and we see the edge. They're exactly the same. So now the edge is going to be that softness that we see in here. So for the edge, we're going to go in there and blur it. We'll give it a little Gaussian blur just enough to soften it up the way the rest of the lighting is being affected, just about like that. Click OK. Now, I need to see the other one on top of it. So I'm going to click on that. Now, we're seeing everything in that red, so I want to be able to differentiate between the two.
So what I'm going to do is I'm going to double-click on this and that brings me up to the Channel Options, which have nothing to do with the performance of the channel but simply in how you see that channel when other channels are turned on. So what I'm going to do is I'm going to change the color of it to a blue. I'm going to increase the Opacity of it to about 80. Click OK and now we can see that difference right in there, see? It's kind of like a slight lilac, purplish kind of tone. And now we can see what's happening. What we're going to do now is, we have our candles right here.
So, this is going to be the main focus of the light. So, what I'm going to do is take the edge, and with my Move tool, I'm going to move it a little to the right. The ring is in register with the ring. The edge is what we'll move. So I'll click my cursor keys just to move it over to the left a little bit, just like that, and move it up a little bit. And there we see this little overlap. Let's move it over some more, and the overlap. So there we see, here's this dark edge here, which is on this side here exactly where it would be. So now what we need to do is to create a single channel that incorporates both of these.
And what I'm going to to do is I'm going to go over here under Image we have a little thing called Calculations. I'm going to bring that up. And the position of these two, is going to make a difference. You've got Source One, and Source Two which is our two channels. So if I put the, my ring up here on the edge. And you see something happen, because the blending is already set to multiply. I'll just set this up to Subtract, take one away from the other. Now you see the position, what it's done. It's created the effect like it's going to be a drop shadow.
So if I put the edge on top and the ring at the bottom, there we see that the inside of the ring is now exposed. And what happens in an Alpha Channel is the selected area is what's white. The protected area is what's black. And the level of gray is the level of selection, kind of like a softened or feathered edge on a let's say rectangular Marquee tool or so on. The same kind of an effect. It will have a softening effect of whatever it is that we're doing. Now I'm going to send that information of what, what's happening here to a New Channel.
I could also send it to just a Selection or a completely New Document if I wanted to keep my mask separate from the file itself. So, I'm going to send it over to a New Channel, click OK and there it is. There's the channel. So when I come back to my RGB, I can now load that channel. I can do it by Cmd clicking here or by coming up to Select and saying Load Selection. At which time, I see the three channels that I have, and I'm going to choose Alpha One. Click OK, and see the marching ants. So what I'm going to do, is I'm going to to hide those marching ants, so we don't see those.
Make it easier to see what we need to do, and layer on top of this. I'm going to draw my highlight from this candle. So I'm going to get my Paint brush, and make sure I have a really big brush, so I'll make it much larger. Nice big brush. And it's very soft edge, yes it is. And I'm going to pick up a color right from here like say, maybe this very light yellow, yellowish tone from right in there, like that. Or maybe pick it up from right here where it's almost white. And then, I'm going to reduce the opacity of my brush.
I can kind of do it lightly. Bring it down to about 50%, and make it even bigger. And I just get this little dare right through there, see? Right there, and we'll give it another. And one more just to make it even brighter. And, one last one right in the middle there, and there you see that, that highlight came in. And on this side we'll just kind of do it once, so it's not as strong as the other side. And there you can see that we have now created the illusion that this ring is being lit from an external light source, or an ambient light from up above, and from the candle that's right next to it, real bright right there.
And if you want that to be even brighter, well, you can switch, switch it to white, and give it a little hit right there, and there's a little whiteness right close to the candle. And we can see that we have a newly lit ring, based on specialized masks called Alpha Channels.
Find answers to the most frequently asked questions about Pixel Playground with Bert Monroy.
Here are the FAQs that matched your search "":
Sorry, there are no matches for your search ""—to search again, type in another word or phrase and click search.
Access exercise files from a button right under the course name.
Search within course videos and transcripts, and jump right to the results.
Remove icons showing you already watched videos if you want to start over.
Make the video wide, narrow, full-screen, or pop the player out of the page into its own window.
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.