What angle works best for projecting digital decorations?
Getting creative with your projector placement will really provide a lot of flexibility when putting together your displays. When you’re first setting up, it can be helpful to point your projector directly at a surface from a perpendicular angle. However, there are lots of instances when moving your projector into a different position can improve your results.
Hiding your Projector
Digital decorating works best as an illusion. If your audience can see the projector, the magic of the effect may be diminished. That’s why many decorators use props to block their projectors from view. Using props works best for front-projection but, if you’re creating a rear-projection display (like a Window Mode decoration viewed from the outside) you still have to consider whether your projector can be seen by your audience.
A common issue caused by projector placement is a “hot spot”. That means that while viewing your display, your audience is looking directly into the lens of your projector, creating a very bright spot in your image. To eliminate hot spots, try positioning your projector lower to the ground and angling the projector upwards towards the window.
You can also raise the height of the projector, either by using a ceiling mount or by placing the projector on a high shelf, then angling the beam downwards.
Hiding a hot spot can be tricky sometimes. Effective projection materials must feature a balance of light diffusion (to reduce the hot spot) and translucency (to improve image quality). Too much of one will cancel out the other.
Depending on what material you use, it may be inevitable that some amount of hot spot will be visible. However, it's important to consider how your audience will interpret the decoration. They aren't as likely as you to notice the projector beam first - they'll probably be distracted by the decoration itself. So, if you can't completely eliminate your hot spot, don't stress about it too much.
Now that you have adjusted the angle of your projector, you may notice some out-of-focus distortion in the edges of your image. Luckily, most projectors allow you to modify the angle of the projected image using a feature called "keystone correction." This lets you project from above or below like in the examples above. You can also project in vertical orientation, which means the keystone will adjust the angle left to right like in the example below.
There are two types of keystone correction, manual and digital.
Digital Keystone Correction
Digital keystone correction changes the shape of the video itself to create a keystone effect. For example, the projector in the AtmosKIT Plus has a digital keystone adjustment of up to 40 degrees on the vertical axis. It's also automatic so all you have to do is change the angle and the projector does the rest!
Some professional protectors also let you keystone horizontally, giving you control to project from nearly any angle. Because the projector is using computational power to create this new custom shape, it requires advanced hardware to accomplish and is usually much more expensive.
Manual Keystone Correction
Manual keystone correction is controlled by a dial attached to an internal lens in the projector which can only adjust on one axis, usually horizontal. That means that if you need to raise up or lower down your projector to project at an angle, you can use the keystone to keep your image in focus. This option is not as ideal, but it's still a helpful feature to consider.