Outdoor Projection Principles
Using 8mm projectors outdoors involves understanding some of the basic principles of projection. First, one needs to understand the basics of how it is that
people see color and brightness.
Human beings don’t see absolute levels of brightness. Instead, people see only relative levels of brightness. This is because our irises contract in such a way that the brightest object will always appear to be the same brightness, no matter how bright it is. The brightness of other objects, therefore, appears relative to that brightest object.
How is this relevant to outdoor projection? The reason that the reason that movies appear so bright when we watch films indoors is that lighting levels are so easy to control inside of a theater. By making the theater completely dark, the movie screen becomes the brightest object in the room, thereby increasing the apparent brightness of the screen itself.
For outdoor movies, this can become a problem. The outdoors is not, as you might have guessed, completely dark. Aside from the moon, there are your neighbors’ lights, stars, city lights reflected off of the clouds, indoor lights and so forth. In addition, most 8mm projectors leak light, which illuminates the area around them, creating even more background lighting. As a result, the image on your projector screen risks not actually being the brightest light around.
In addition, black on a movie screen is a problem with any other sources of light. Black in a movie is simply where no light is shone onto the screen. As a result, black in your movie will actually appear as whatever color the screen appears when the film is not running. As a result, the more background lighting there is, the less black your blacks will appear. With significant ambient lighting, your movie will look a little like a movie on your computer where you’ve turned up the brightness but turned down the contrast. All the blacks turn to a dull grey.
Proper 8mm Outdoor Projection
In order to correct for the ambient lighting in your outdoor space, you need to make sure that your screen is the brightest object. Remeber that we always see the brightest object at the same level of brightness. As a result, even if there is a lot of ambient lighting, if you can make your projection surface the brightest object outdoors, it will still appear reasonably bright.
Unfortunately, 8mm projectors are not exceptionally bright, especially when compared to video projectors. A typical 8mm projector will generate about one-thousand lumens of light. A “lumens” is a unit of brightness as measured coming from a single direction. Since 8mm projectors are not very bright, the size of your screen cannot be especially large. At the largest, your sceen can be six feet by four feet. After that point, the ambient light will start to become brighter than the screen and your entire movie will look dim (note that this would not be an issue inside, as nothing is brighter than your screen in a dark room).
Even once you have accounted for brightness, there is still the issue of blackness. Unfortunately, there is really no good solution for this except to orient your outdoor movie event in such a way that your screen is not facing the brightest sources of light. After all, projector screens are designed to reflect all colors that hit them from the front. Therefore, if you can minimize the amount of light that hits your screen from the front, you can improve the quality of your blacks.
One option is to use some sort of tarp or canopy over the area where you host outdoor movie events. If your outdoor projector screen is under some sort of cover, moonlight, starlight and cloudlight will not hit it, creating truer blacks.
8mm Projectors can provide an excellent outdoor film-watching experience. However, in order to have the best outdoor events, it is important to understand brightness and color and how to make the most of your 8mm outdoor projectors.