Q. I am a second year Education student and I was wondering if you could give me an answer to the following question I have as a student I am teaching on my rounds has asked me...
If movies are projected onto a white screen, how is it possible to see black, and other dark colours in films?
If you are unable to help me could you please refer me to someone who can.
Thank you
Emma
If movies are projected onto a white screen, how is it possible to see black, and other dark colours in films?
If you are unable to help me could you please refer me to someone who can.
Thank you
Emma
Answer
In a completely dark room, even a white screen will appear black, since there's no light reflecting off of it. So, the "black" portions of the image are just the areas of the screen where the projector isn't shining any light at all.
Even if the room isn't totally dark, the areas of the image that are supposed to be black will still appear to be black if the adjacent areas are much brighter. It's essentially tricking your eyes because your eye depends as much on the contrast between adjacent parts of the image to determine bright/dark as it does the actual brightness level of the image.
If you take a white screen in a moderately well-lit room and project an image consisting of alternating white and black squares, the black squares will still appear black (or at least a dark grey), just because the adjacent white squares are so much brighter.
Even though the screen looked "white" to you when nothing was being projected onto it, the non-illuminated portions will look dark compared to the portions that have bright white light reflected off of them.
In a completely dark room, even a white screen will appear black, since there's no light reflecting off of it. So, the "black" portions of the image are just the areas of the screen where the projector isn't shining any light at all.
Even if the room isn't totally dark, the areas of the image that are supposed to be black will still appear to be black if the adjacent areas are much brighter. It's essentially tricking your eyes because your eye depends as much on the contrast between adjacent parts of the image to determine bright/dark as it does the actual brightness level of the image.
If you take a white screen in a moderately well-lit room and project an image consisting of alternating white and black squares, the black squares will still appear black (or at least a dark grey), just because the adjacent white squares are so much brighter.
Even though the screen looked "white" to you when nothing was being projected onto it, the non-illuminated portions will look dark compared to the portions that have bright white light reflected off of them.
Big flat screen or projector + screen?
Q. Me & my BF have decided to set up a nice home theater. Lots of our friends are into movies and sometimes we all get together to watch a show every week (like a Survivor party). My BF says we should get a projector and a screen and have a really gigantic picture. I say we should get a 52" lcd or something like that. What factors should we consider each way?
Answer
Is this in a dedicated HT room with good light control? If so, projector+screen is the only way to go. If not, then you need to consider the amount of ambient light in the room. If you're able to darken the room nicely (and don't mind doing so), you and your guests will enjoy the larger screen. If you can get the room reasonably dark, you could still do well with a bright projector (shoot for 2000 lumens or more) and/or a high gain screen.
An LCD can be watched in full daylight, almost without worrying about how bright the room is, and that's nice, but THX recommends a screen that's diagonal measurement is .84 times the viewing distance. So, for example, if you'll be sitting 10 feet away, THX recommends a 100" screen, so a 52" screen is really way too small. Especially for watching movies.
When picking out a projector, a couple of outstanding resources are http://www.projectorcentral.com which has detailed specs and an awesome projection calculator. (Here's an example: http://www.projectorcentral.com/CalculatorLoader.swf?MET=0&VERSION=2.14&PART_ID=3884) The other is http://projectorreviews.com - the most in-depth, thorough and helpful projector reviews on the web, in my opinion (lots of screen shots and comparisons, too!)
One last recommendation- don't skimp on or underestimate the importance of the screen. Many people spend a couple thousand dollars on a nice projector, then buy a $300 or $500 screen. It makes a much bigger difference than you might think. The best (commercial) screen I've seen is the Vutec Silver Star. (http://www.vutec.com/Products/Vutec_Fixed_Frame_Screens/SilverStar) it's a high gain screen, so it can help offset ambient light issues, too. It only comes as a fixed (doesn't roll up) screen, though, so it's best suited to a dedicated theater room. If you need something that rolls up (or something that's acoustically transparent- allowing you to place the center channel speaker behind the screen for excellent dialog localization), go with something from Stewart, (http://www.stewartfilmscreen.com/FrontProjection.html). Another option (if you or your boyfriend are handy) is a DIY screen. These are usually fixed, rather than retractable, but you can get very close to the performance of a Vutec SilverStar at a fraction of the cost. Get a good education and learn how on AVS Forum (http://www.avsforum.com/avs-vb/forumdisplay.php?f=110).
Good luck and have fun!
Is this in a dedicated HT room with good light control? If so, projector+screen is the only way to go. If not, then you need to consider the amount of ambient light in the room. If you're able to darken the room nicely (and don't mind doing so), you and your guests will enjoy the larger screen. If you can get the room reasonably dark, you could still do well with a bright projector (shoot for 2000 lumens or more) and/or a high gain screen.
An LCD can be watched in full daylight, almost without worrying about how bright the room is, and that's nice, but THX recommends a screen that's diagonal measurement is .84 times the viewing distance. So, for example, if you'll be sitting 10 feet away, THX recommends a 100" screen, so a 52" screen is really way too small. Especially for watching movies.
When picking out a projector, a couple of outstanding resources are http://www.projectorcentral.com which has detailed specs and an awesome projection calculator. (Here's an example: http://www.projectorcentral.com/CalculatorLoader.swf?MET=0&VERSION=2.14&PART_ID=3884) The other is http://projectorreviews.com - the most in-depth, thorough and helpful projector reviews on the web, in my opinion (lots of screen shots and comparisons, too!)
One last recommendation- don't skimp on or underestimate the importance of the screen. Many people spend a couple thousand dollars on a nice projector, then buy a $300 or $500 screen. It makes a much bigger difference than you might think. The best (commercial) screen I've seen is the Vutec Silver Star. (http://www.vutec.com/Products/Vutec_Fixed_Frame_Screens/SilverStar) it's a high gain screen, so it can help offset ambient light issues, too. It only comes as a fixed (doesn't roll up) screen, though, so it's best suited to a dedicated theater room. If you need something that rolls up (or something that's acoustically transparent- allowing you to place the center channel speaker behind the screen for excellent dialog localization), go with something from Stewart, (http://www.stewartfilmscreen.com/FrontProjection.html). Another option (if you or your boyfriend are handy) is a DIY screen. These are usually fixed, rather than retractable, but you can get very close to the performance of a Vutec SilverStar at a fraction of the cost. Get a good education and learn how on AVS Forum (http://www.avsforum.com/avs-vb/forumdisplay.php?f=110).
Good luck and have fun!
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