Let’s go through a few terms that everybody uses, but might have a different meaning depending on who you talk to. We care about the specific meaning that will correctly get an idea across to the Tech Team about a problem so it can solved quickly and well.
First, Contrast – Simply said, in the cinema, it is the range or difference between what looks like white and what looks like black on the screen. In most auditoriums, there is no real white on the screen or real black on the screen. There are many reasons for this, and it will always be. But there is a range that each room is capable of, and the equipment is in a war to try to make it stable, which it always loses. A bulb gets weaker, electronics get too hot or finds some other reason to fail. The screen material gets darker every week and month and year as it ages, and sometimes computers just don’t talk to other equipment correctly.
Since it is your job to ensure quality, it is your job to decide whether contrast has reached a point of concern. So, it is time to learn how to judge it. Here are some examples.
When you see someone’s leg under a table or something in a shadow during a movie, you have an opportunity to “See Into The Dark”. At worst, you won’t even see that a black shoe isn’t part of the shadow. At best, you will see that there are different shades of black and grey in the shoe and sock and the pant cuff and the folds in the pants. Notice these things in real life, notice how there is a constant gradient in dark shadows, and how a colored floor will go off to black in the distance.
The opposite will happen in the brilliant whites and colors. There will be ‘blown out’ white where things are not distinguishable at all…just one flat and too-bright-to-look-at white. The funny thing is, the brightest that the very best projector and screen combination can create is 100 units of light, and most strain themselves to create half that.
[The standard is 48 candela per square meter, which simply means: the amount of light that would be created if you held 48 candles at a distance of one meter (3 feet) in front of the screen, then measured all the light reflecting from one square meter of the screen (which is about nine square feet).]
Outside, 100 units are nearly nothing. The reflection of the sun on a car is thousands and thousands of units. (Perhaps we should stop saying ‘units’ since people in the industry call that unit of light a ‘nit’.
On-screen, look at some bright part of the sky or something flat and nearly one color – a refrigerator, for example, or even a close up a white dog. The white should actually be many shades of white. You’ll see that this is true of a real dog, or a real sky, and the same is on screen: One solid, flat color is wrong (except in a cartoon!) A smooth gradient of white to lighter or darker white, or another color is correct. There will be shadows in the hairs of the close up of that white dog as well.
So, that is your task. Learn about Contrast by looking: What looks natural in real life and on screen. At first you will write to the tech and say, “In auditorium 5, it really seems like something is wrong in the shadows, but I don’t know what…it is better in the other rooms.” As your abilities grow you’ll be able to say, “The gradient in the darks is off in auditorium 5, they get muddy too quickly. The blues especially seem wrong…it seems like the yellows go toward the brown instead of toward the greens.” Won’t that be fun?
Do well and enjoy the ride.