3) A Look at Light, Part 2

There is a rule in technology. Engineering is the Art of Compromise. It applies to sound as well as picture, it applies to the equipment that creates sound and picture, it applies to safety equipment and the carpet that we walk on.

It means that there is almost always a trade to make between speed or size or cost or portability. Maybe you want more light on the screen, but that will give you more scattered light too, and that is not a good thing. Or you think, OK, I won’t let it scatter, I’ll direct the light using curved screens and screens of different materials. But directing light will bring you ‘hot spots’ and that can be worse. We are surrounded by the decisions of designers who have to balance these things everywhere in our daily lives.

There are machines, tools really, that will test light and sound. They are usually expensive, and they require trained people to set them up properly. These people must then take the tests properly and then read the results properly. So, it isn’t only that the equipment costs 15,000 to 30,000 dollars or euros. They also consume expensive technician time. Which doesn’t seem horrible, except that there is only so much money coming in from the sale of tickets and  popcorn and sugar-water. One of the compromises of digital cinema was that they make a fine picture without a lot of employee interaction, but they are incredibly expensive compared to the film projectors that cost ¼ as much and lasted 50 years. How many computers do you know that last even 5 years? 10?

Well, how about the 6,000 euro or dollar units? The quality might not be as good as they real expensive ones, but are they are good enough for some purposes? Sure. But again the compromise. How often does something go bad, and how bad are the effects of that happening? Maybe a show is lost for a day, or more rarely a week. Is too much red in the picture or a rattling speaker going to make the people leave? Will they notice? Will they say something, perhaps ask for a refund? Or will they notice and just never come back?

The compromise is that it isn’t worth buying even a less expensive unit, and leaving it for an untrained person to lose or break. There is some equipment that doesn’t cost as much and doesn’t need any human intervention, but they are quite weak in abilities.

So, this is where we come in. We have over a million sensors in each eye, and almost 25,000 detectors in each ear. We may not be able to count wavelengths and levels with as much exactness as a microphone and color sensor, but if we learn how to look and listen, we can do what the job requires, and we can be aware of things…we can report things…that a machine just isn’t going to be able to do.

And, get this, the phone we carry around is able to give very accurate clues too.

There is one thing that a computer based device is that we are not. Consistent. If we ask it to make a measurement every day at 6AM, it will. We get distracted by other chores or being tired of other chores. Life sometimes throws us a variable; the car doesn’t work, the this, the that. How does our carbon-based/oxygen-buring body compete with the silicon-based electron eating computer system? We just have to get through our checklists with a DCP playing in each room every week.

Each slide of each test DCP is a different tool. The first time we see the different slides, we won’t know what story each one can tell. But after a while, you may think, “I never noticed that line going across the picture being jagged…or not as bright…or blurry.” You may not be sure of yourself the first or second time you see it. But any of those things are a perfectly good observation to pass on. And if you are right, learn to be sure of your awareness in the future. And if you are wrong, ask the technicians how you got it wrong. You are trying to make their life easier and more efficient.

The following picture is something that you will see a number of times, perhaps in different variations. The top bars are two gradients of 90% to 100% black and 100% to 90% white. The second bar has the two gradient reversed. What can you do with them?

Basically, they should be perfectly smooth – you shouldn’t be able to see any steps in the gradient at all. The same is true for the left side of the lower bars which are a set of 100% black to 0% black (which is also 100% white of course) and below it is the reverse. There should be no steps, and the difference with between them and the difference between the black background should be clear.

The magnifying glass won’t be on the master, but it is there to show where you should see 3 sets of the numbers ‘100’ and ‘0’ if the projector is set up well. If you don’t see numbers at all, then there is a problem to report. You might report only 2 showing, and the tech may tell you that this is the best that a certain projector can do. But, the tech might also point out that a different machine should show 3, and you should point it out when it doesn’t.

Pluges Plus steps of greys

You might also use this slide to help detect bulb flicker. Bulb Flicker is the effect that happens as a bulb in the projector gets old. Sometimes, it won’t be old, but mis-aligned. If you can catch a bulb that is misaligned before it completely damages itself, which will give it back hundreds of hours of life instead, you have saved hundreds or maybe thousands of money units.

Sometimes you won’t notice bulb flicker when directly looking at a slide up close, but if your head turns to the side a little you will notice the fast pulsing or flickering. All bulbs do it as they get older. Customers may not notice it, but they will be annoyed by it as it can make a person uncomfortable. Let the tech know when it gets pretty strong.

You may notice in the boxes that it seems as if the colors at the edges are darker than the box itself…like there is a ramp at every one. But if you get close and really look, you will see that they are perfectly flat in color. This is the Mach Effect. It is an optical illusion.

Inside the boxes is only one number, and you should be able to see it. Technically, on the top row the number is 5% darker than the shade of the box, while the bottom row is 5% lighter than the shade in the box. 50% is repeated, with one of each. If you can’t see the difference, that would probably indicate a problem to mention, that the contrast is getting worse. It is also getting worse if you can’t distinguish the boxes from each other. 95% and 100% should not look the same. 90% and 95% should not look the same. The same for 0% and 5% and 10%.

This blown up example won’t look as good on your computer monitor, but it will hopefully look great on your screen!

Here is a different thing to look for. In this shot you can hopefully see that there is a 1% difference between the different diamonds of the slide. The circles should have a nice bright dot in the center, not grey!

OK; that’s a long enough lesson. Getting out there and looking hopefully be more fun and productive.

As always, ask questions.

 

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