Union is a photo editor that lets you create cool-looking blended and double-exposure photos in only a few steps. With several tools to adjust each image so that they look good together naturally, it's one of the best apps of its kind, but it requires more than a bit of work on your part. What's more, images need to (ideally) be of a specific type -- a type that most people probably don't have handy in their photo libraries. Get past these hurdles, though, and you'll like what you see.
Union is from developers Pixite, who have plenty of experience with photo editing apps. The company has already seen success in the App Store with popular artsy photo manipulation apps like Fragment and Tangent.
Learning the basics
Union lets you blend images together and gives you several tools to adjust each image so that they look good together naturally. But there are a few steps you need to go through with Union to get a good looking result.
Blended images are probably the easiest to make, requiring you to choose one image, then choose another, then adjust the transparencies so that they fit together.
You start by loading a background image, solid color, or transparent layer, and make sure it's the size you want using several common sizes such as 1:1 5:4, 3:2, or 16:9. Next you add a foreground image, solid color or transparent layer. Finally, you can add a mask to make the two previous images fit together better by erasing part of the image, or adding another image or shape.
If it sounds confusing, it's because it is, and it took me a few tries to understand how each of the different layers worked together. But when you're satisfied with the look, you can make several minor adjustments to change the transparency, make the colors pop, and other basic edits.
When you're finished, you can open your blended image in Instagram (along with other supported apps), save it to your camera roll, or use the iOS 7 sharing features to send it to iMessage, Mail, Twitter, or Facebook.
Making more complex projects
While blended images are neat in their own right, most people will probably use Union for making double-exposure images. You have most likely seen examples on the Internet, in magazines, and other places, but the easiest way to describe the double exposure is to imagine the silhouette of a person, with a landscape photo (such as a flowing field or sunset) that fills in the outline of the person. It's a unique effect that's really eye-catching.