Join Bert Monroy for an in-depth discussion in this video Creating a shadow from the light fixture, part of Bert Monroy: The Making of Amsterdam Mist, the Structures.
So there's our little shadow that we created in the last movie from the little lamp that we created in the last movie. Now we might want to do a little thing to it. I'm going to lengthen it a little bit. So let me go in there and just kind of pull it down. I want to make it longer. So it's a really early, noonday, long shadow from above and so on. So there. So now, I want it to get softer as it gets further away. So I'm going to do another blur. Except this time it's going to be really strong down here and becoming less as it goes up. And there's where we need an alpha channel. So what I'm going to do is I'm going to come over here to my Channels, and I'll say, give it a channel. And I want to see the rest in place.
Now a channel is kind of like a mask, but it's a different type of mask. It works exactly like a layer mask, where it's black you won't see the layer, where it's white you'll see it. Level of gray in between the black and white is level of visibility. Well the alpha channel works the same way, except it's not a way of seeing it. It's a way of exposing it. Of exposing it to an effect, a way of selecting it. So, I don't want anything to happen up here, so that's going to remain black. And I want to gradually happen and really strong down here, which is going to be white. So the gradual in between will be caused by the gray.
So I'm going to get my gradient tool. Make sure it' set to Linear, and black to white. And I want to go to where it's going to be full strength, which is right about here. And from here down, it's going to start to soften up. So I hold down my Shift key to constrain it, and I go down and fade to about here. And that's where the white, that's where it's going to be full effect, see? This is what it looks like. So, now, we go to the RGB. And what I'm going to do, see it didn't do anything to the art yet. What I'm going to do is I'm going to go ahead and load this by command, clicking on it.
And there, you see the marching ants from the 50% gray over to the white. We're just going to hide those marching ants. And what I'm going to do is apply that blur that we did before. And you notice how it's happening more towards the bottom. Now instead of doing brute force which is going to to give us this weird effect like this, I'm going to do it a little bit at a time. So we'll just go in there and about like that, click OK. And then apply it a few more times. Cmd+F, Cmd+F, Cmd+F. See how it's getting softer as it get further down, whereas up here, it's staying pretty straight? So now that we got that, it also will be affected by ambient light. because you can see the strength right here in the center is just as much as here. So what I need to do is have ambient light affectors.
And so, to that layer I will apply a layer mask. Now, it's still selected, so undo that. What's happening there is that we have that same alpha channel, and it was still selected. I turned off the marching ants. That's why we didn't know it was selected. That happens a lot. You make a little mistake like that, no problem. So what we do is, I'm going to Deselect it and give it that Layer Mask. There it is. Now, I don't want it to completely disappear. So, instead of black, I'm going to use the gray, say about that dark. Click OK, and I'm going to do the Gradient. Now this time I'm going to go in reverse. I'm going to go up because I want to start with the gray, which is where it's going to hide at the most, to the white, which is going to expose it the most. And I'm in the Mask. So I go in there and I'd say, right about here, I say, up. And there you can see where it's gotten slightly hidden. Now it's maybe a little too much, so let's undo that.
Let's start right below it and go up. There. Now we can still see the full shape but it's getting lighter as it gets further away giving us this nice realistic looking light