Create the Double Exposure Effect Without Photoshop

Hi, this is Gary with MacMost.com. Today, let me show you how to create the double exposure effect on your Mac without using Photoshop or really any graphics app at all.

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So the double exposure effect is when you combine two images, one on top of the other. You kind of blend them together. But it's a little more than that.  You only want the combination to happen in a certain area of the photo. Now usually people use Photoshop or some other graphics app to create that. But you can actually do it just using Keynote on your Mac. The result isn't perfect but it's pretty easy for anybody to do.

So here in Keynote we're going to start with a basic black template. I'm going to remove the text that's in there and I'm going to change the size of the document to something different than just the standard widescreen. I'm actually going to set it to exactly the size of the image. Looking at the image I could see it's this particular size right here. Your image, of course, is going to be different. But the idea is that now I've got a slide that's at the exact size. Let me shrink it down a little. I'm going to use Command, Shift, and then Less Than so now I can see the entire slide and little bit of the area around it.

Now I'm going to drag and drop that image from the Finder into the slide. You could see it appears here. Now this type of effect works best when you've got a subject, like this, that's well separated from the background. So you see the nice uniform background here and there's the subject. So you can't just start with any image. But we'll look at this one and we'll look at another example in a bit. 

So the first thing we want to do is prepare this image so it can be combined with another. I want the combination to happen over the head here. I don't want it to happen here over the background. To do that I'm going to go to Format and then Image. This is with that image selected. Then use Instant Alpha. Now you may have already used Instant Alpha for something else and you may already know that you can click on something like the background here and drag a little bit to select the entire background but not too much. We're not actually going to do that here. I'm going to hit the Reset button at the bottom. We're actually going to do the opposite. 

I want to select the woman here, not the background. That's a little tougher. So if I click somewhere in her skin and drag away a little bit you can see it selects more and more of her but eventually it selects the background. I want to back off when I do that and not select the background at all. So you can see it only selects a portion of her. Well you can keep clicking and dragging to select more of her. So I could do that each time making sure I back off before I select any of the background. So I'll do that with her hair here. I'll do it with a little bit more of her hair. I'll keep going until I've selected enough of her. It doesn't have to be perfect as long as I don't get any of the background. It's going to take several different attempts here to keep grabbing more and more until eventually I have enough. It doesn't have to be everything but the more you get the better the effect will look. So you see here I've grabbed quite a bit and I'm going to hit Done.

What's going to happen is everything I've selected is now going to be cutout. So the black you're seeing here is actually the black background showing through. Now we can bring in another image. I'm going to bring in the image of a sunset and I'm going to drag that in. Now this is going to be a smaller image than the previous one so I'm going to expand it a bit to make sure it covers the area very well. Then I'm going to send it behind the first image. So I'm going to Arrange, and Send Backward or Send to Back. Send Backward sends it back one step which is all I need now. So you can see how it appears behind her. At this point I can see there are pieces of her hair that I missed. I can click here on the background to select that image and I can go into Instant Alpha and I can continue to grab more areas. So I can make this even better. Then I'll hit Done. So now I've got most of it. You can get a little more detailed when you work.

So now you can see here that I've got the front image and it has a hole in it and a back image showing through. This isn't really what we want. We want to combine the images. We don't want to just have a cutout with another image showing in it. So to combine them you would do something completely different if you were using a graphics app. But here in Keynote the trick is going to be to select that original image. I'm going to copy and paste it so I'm creating a duplicate of it. I could also have used Duplicate Selection or just Option and Dragged. 

Now I have a second copy of the cutout. What I'm going to do is I'm going to leave that right there over everything but I'm going to go to Instant Alpha and I'm going to hit Reset. So that goes back to the original version of that. Now I'm going to hit Done. I'm going to go to Style and look for Opacity. Here I'm going to make it semi-transparent. As I do it's going to reveal the image behind it. So I have three layers here. I've got the regular image but semi-transparent here with Opacity set to something less than 100. Then I've got the image but with the head cutout. Then behind that I have the image of the sunset so it shows through.

Now I can drag the sunset image to position it exactly where I want. I can scale that. Sometimes it can be hard to grab an image that's between other ones. But in this case since the sunset image is going to be scaled larger I have all this area around it to grab. So I can go ahead and scale it and set it to the position I want. I can click to select the front image there and set the opaqueness so I could basically have it be half an image of her and half an image of the sunset with the area out here, the background, actually being completely 100% background. It's a semi-transparent version of the background over a completely opaque version of the background. So it combines to just be the background.

If this weren't yellow, if this were something else like other people and other things going on behind her you would still see that as 100%. You would only see the sunset coming through here with her. You could easily replace this background here. So let's drag a skyline, for instance. Put that back there. Then I'm going to Arrange, Send it to the Back, and you could see how it shows through there. I'm going to want to scale this quite a bit and set it up like that. So now you've got that there as the background. That may require a different, you know, Opacity for the head there depending upon how strong the background image it.

Now as another example let's go and get rid of the woman there and go with this background here as the main image that we're going to use. So I'm going to scale that up. Normally I would make the Keynote slide the exact size of this. Now I'm going to cutout the skyline here. So I'm going to go to Image, Instant Alpha, and then I'm going to select the buildings. It's not going to be perfect. I want to back off as soon as I see it start to select something else, like the water like that. So go to about right there and then see what it is I missed. So there's part of that building. There's the top of this tower here. I want to think whether I want these sails to be in it or not. 

Now here's a trick. Not only can you click and drag to select things, but you can Shift, Click, and Drag to deselect them. So I can deselect this sailboat here by Shift clicking and dragging in it so I can get the sailboat back into the picture. You can also, of course, use Command Z to Undo which is very useful when you're working with this.

So I'll get this image where I want it to and hit Done. So now I've cutout the city skyline there. Let's bring something else in here. I'm going to bring in a background of some trees and I'm going to set this up to be behind the city. Let's go to Arrange and Send it to the Back. So now you can see the tress showing through the buildings. Let's go and select the buildings again. I'm going to Copy and Paste. Let's just do the Duplicate Selection there. Go to Instant Alpha, Reset so this one in the front is just the original photo of the skyline. But I'm going to go to Format, Style, Opacity and set it to be semi-transparent. So now I've got the trees showing through on the buildings. I can match the bottom of the trees right there with the water. Maybe scale it up a bit like that. So now I've got the trees and the buildings on top of the trees combining those two ideas. Notice the sailboat is in front of them all because I subtracted that from the alpha so it's not being replaced by the trees in either layer. 

So now that I've got that how do you then Export this. Well, you go to File, Export To, and then you do Images. You can export it in the format. Let's do JPEG high quality. You can go PNG if you want top quality. Export this out. It creates a little folder there with the name of the Keynote in it but in there is your image. You can take a look at that. It's just a regular JPEG image that now you can use.

So it's a lot of fun to play with. As I said before pros will do this using Photoshop or some other image editing app. But if you want to create the simple effect without investing in new software or you find this process a little bit easier since you already know Keynote, it allows you to do basically the same thing. Although if you want to use more effects and get even more detailed then it kind of becomes necessary to move on to software like Photoshop.