094 Masking a real-life shadow

Hey gang! This is Deke McClelland. Welcome to Deke's Techniques! Now, a long time ago, back in year 2011, I made a couple of videos in which I showed you how to take a red car and first make it gold and then make it black. We got so much positive feedback that I thought, give the people what they want. More car stuff! So we're going to take this car, and we're going to mask it against this different background. It looks hopelessly fakey of course, which is why we need to mask back in its shadow, and this is a shadow that will work against any and all backgrounds.

Here, let me show you exactly how it works. So the whole idea is I want to take this taxicab and I want to extract it from its mundane background using some vector masks, and then I want to place the cab against a more exciting background. Even though this is an impeccably rendered mask, the cab doesn't look like it belongs here because it's not interacting with its new environment by casting a shadow. I'm going to show you how to create that shadow in this video and that way, you can composite this image against any background that you like.

Let's go ahead and switch over to this image here and notice, if I zoom out, that I had to slightly rotate the cab image to straighten it out, so as a result, we have these little wedges toward the top and along the left-hand side of the image. We'll make life a lot easier for ourselves if we go and fill those wedges with white, and you can do that by dropping down to the bottom of the Layers panel and clicking on the little page icon to make a new layer, then go up to the Layer menu, choose New, and choose Background From Layer, and that will create a new presumably white background, assuming, that is, that your background color is set to white.

I'm going to go ahead and zoom back in. Now we're going to capture that shadow using the Calculations command, and Calculations allows you to merge two existing channels in order to create a base alpha channel. I typically look for the channels in the image that contain the most contrast, and in the case of this image, the red channel provides us with the brightest version of the shadow, also contains a lot of detail, and then the blue channel offers the darkest version of the shadow, along with a lot of contrast. So I'm going to switch back to the RGB Composite.

Then I'll go up to the Image menu and choose the Calculations comman. And the first thing you want to do is make sure both of your layer options are set to Merged. That way, you're drawing the channels from the merge composite view instead of some single channel, which won't do you any good. Next, make sure the first channel is set to Red, as it is, and the second channel option, change that one to Blue, and then the Blend mode really depends on your intentions. If you want to create a really dark shadow then Multiply is a great way to go. If you want a high-contrast shadow, then I suggest you choose Overlay.

I however want to stick with a pretty bright shadow, because I want to be able to easily see what's going on inside it, so I'm going to choose the Screen mode. We can always darken that shadow up later if we need to. Now, click OK to create a new alpha channel, and I like to rename these things, by the way, after how I got to them in the first place. So I'm going to call this A+B screen, and then I'm going to make a copy of it by dragging it and dropping it onto the little page icon at the bottom of the panel. Now, duplicating channels as you work is a good idea, because after all, we're having to work with a flat image.

There are no layers here inside the Channels panel, and so every modification you make is destructive. So I'm going to rename this channel Clean Up, and that's exactly what I'm going to do. I'll grab my Brush tool, which you can get by pressing the B key. Make sure your foreground color is set to white, right-click inside the image, and make sure the Hardness value is cranked up to 100%. Then we want to click right along the corners of the shadow, that is, the points at which the shadow intersect with the car. So right there is one of those points. We want to get rid of it. And then the other one is right here along this left tire. Go ahead and click at that intersection as well to paint that area away.

And then you want to paint the snivels that you see, the little sort of dirt flecks and stuff like that, the edges of the pebbles outside here in the larger area that should be white. Don't paint that thing away, because that's the shadow of the rearview mirror and we want to keep it intact. But this little guy needs to go, as does that guy as well. Do not paint away any of the shadow. Now, I will go ahead and switch to my Rectangle Marquee tool by pressing the M key. I'm going to surround the top portion of the car like so, and then press Alt+Backspace or Option+Delete to get rid of it, click off the selection in order to deselect the image, go back to the Brush tool, and paint along this area here.

Notice that I'm not painting away the tires, nor am I painting away the bottom edge of this bumper. I'm trying to keep that detail intact, so that we have something to overlap into, essentially. If you were to take a close look at this image--and depending on your monitor, you may see this as you work along here-- but we actually have a little bit of light gray going on outside the shadow. To clean that up, go up to the Image menu, choose Adjustments, and choose the Levels command, or you can press Ctrl+L or Command+L on the Mac, and notice this little bit of histogram over here in the far right-hand side.

If I was to drag my black slider up beyond it, you would see that we've got these obvious globs around my brushstrokes. To get rid of those, move that black slider all the way back to the left so that the first value is 0, and we want to take this white point value down to 235 so that we're cutting all that stuff away. And you know what? Let's take it down just a little bit farther. We'll take it down to 225. How is that? We'll take it down to 225, and that way we get rid of all the stuff. Now, click OK.

If you take a pretty close look at the shadow, you can see that it's got this kind of smudge in front of the driver- side tire, and that is not consistent with our other backgrounds at all, so we need to get rid of that as well as cover up some of the other sort of bits of gravel and gunk throughout the image, and we're going to do that starting with the Dodge tool, so go ahead and grab that tool. Notice I've reduced my Exposure value to 20%, and I am now going to paint over this smudge a few times here. So by virtue of the fact that we're working with such a low exposure value, we have the option to paint multiple times.

Now, I'm going to paint over these guys as well a little bit, and then we're going to heal away some stuff by grabbing the standard Healing Brush tool and then Alt+Click to set a source, Option+ Click on the Mac, and click in order to paint away the details. Basically, we need to get rid of some of this texture, because again, we've got a lot of gravel underneath this car, a lot of sort of street details, and we're going to be setting this car onto other surfaces, onto fake grass in the case of that grass and sky illustration, and then we're also going to set the car on a real beach environment.

That was a terrible edit. So I'll undo that one and try again, and might as well try painting over some of these details as well, see what we can do. Now, I'm not going to worry too much about it. I'm just going to try to get rid of most of the junk, because we are going to be following this up with a dose of Gaussian blur in just a moment. So I'll go ahead and paint that guy away, then Alt+Click here, and paint that detail away like so. And otherwise I think this looks pretty good, You might as well paint some these guys away in the background, and then this thing near the tire also wants to go.

So paint as much as you want. When you grow tired of the process then here's what I want you to do. Just go ahead and zoom back out, go up to the Filter menu, choose Blur, and then choose Gaussian Blur, and where this image is concerned, I went ahead and set the Radius value to 8 pixels. If you're working with a higher- resolution image, you would go with a higher Radius value. I'll click OK in order to apply that effect, and then I'll go up to the Edit menu and I'll choose Fade Gaussian Blur, and I'll reduce the Opacity value to 50%. So we've got a 50-50 combination of blur and original detail.

I'll click OK in order to accept that modification, and now I want to darken things up just slightly by pressing Ctrl+L or Command+L to once again bring up the Levels dialog box. I'm going to click on that central gamma value and press Shift+Down Arrow three times in a row to darken up that shadow and then click OK. Now, we're ready to add the shadow to the image. Go ahead and load the shadow as a selection by Ctrl+Click here on the PC and the Command+Click on the Mac. Then switch to the RGB image. You also need to bring up your paths, by the way, so go to the Paths panel and click on that car outlines collection that I've created for you in advance.

Then switch over to Layers panel, and we need to mask the car for starters here, so click on the cab layer. The interesting thing is we've got both the selection outline and the collection of paths going on screen. If you were to click on the Add Layer Mask icon, you would convert the selection to a standard pixel-based layer mask. But if you press the Ctrl key or the Command key on the Mac and click on that icon then Photoshop ignores the selection outline and it converts the path outlines to a vector mask. Now, I'm going to turn on the Lawn layer, and I'm going to click on the Beach layer to make it active, and then I'll press Ctrl+Shift+N or Command+Shift+N on the Mac to make a new layer.

Let's go ahead and call it Shadow and click OK. Notice that I've already dialed in a foreground color here that has a Hue of 25°, a Saturation value of 75%, and a Brightness of 5%, and you can get the HSB sliders from the Color panel flyout menu. And with that color dialed in, I'll press Alt+Backspace or Option+Delete to fill the selection with that foreground color. The problem is, I've got the wrong thing selected. All right! I'm going to press Ctrl+Z or Command+Z on the Mac to undo the fill. Now, when we were working inside the Channels panel, we built the shadow as black against a white background, which is the easiest way to gauge our progress.

However, what we want to do is actually select the opposite area. So go up to the Select menu and choose the Inverse command, or press Ctrl+Shift+I, Command+Shift+I on the Mac, switch back to the RGB image, and make sure that shadow layer is selected. Then press Alt+Backspace, or Option+Delete on the Mac to fill the selection with darkness. I'll press Ctrl+D, Command+D on a Mac. This is a very dark color; however, it's not entirely black, which means that we need to burn it into the background by switching the Blend mode from Normal to Multiply to produce that effect there.

As I was telling you upfront, this is a versatile shadow, so you can set it against any background that will accommodate the car. All right! I'm going to press the F key a couple of times in order to switch to the Full Screen mode. Go ahead and zoom in as well. Here is the actual real-life shadow drawn from the original car image using the Calculations command, along with some alpha channel cleanup, here inside Photoshop.