Help with Projector display


I wanted to get a screen for my projector NEC LT380. My projection has some extra white space behind the actual image. The projector displays the image on the screen but has some white space on top and bottom and some on sides which is just projection of white space but I can enlarge the display to fit that screen. 

Could you please suggest what this is and how I can fix it. I appreciate it a lot. Thanks.

Sorry you are not describing it very well. Are you saying the image won't zoom big enough to fill your screen? In that case the projector is too close and will have to be moved back. Otherwise you would search menu options for screen and aspect ratio until you find the right match. 

Be aware that not all movies are in the same aspect ratio. Whatever aspect ratio your screen is, only movies that match that aspect ratio will fill the screen. But usually the part outside the image is black not white. So again not real sure exactly what you are talking about.
I use a 4:3 projector screen and roll down to the height that match other aspect ratio.
So when I project the screen is say 5 feet in height. Then I project a movie or tv shows from the roku or computer, the screen is filled 3 feet with the movie or tv, and 1 feet of screen space on top and bottom is still there which is just a plain projection or light. I have a picture but don't know how to upload here. Thanks.
What is the exact height and width of the screen?   What is the make / model of the projector. 

It sounds like an aspect ratio mismatch between the projector and screen.
Never heard this before so had to look it up. Your projector is a business projector that can work for home video but is not primarily designed for watching TV and movies. So again like I said before you are going to have to search around the menu and figure it out.

Part of what you’re seeing is due to aspect ratio and that part is normal. TV and movies are shot in different aspect ratios. That is the ratio of width to height. The aspect ratio is different even from one movie to the next. But while the movie aspect ratio changes your screen stays the same. So what is supposed to happen is when the aspect ratio gets wider for a wide screen movie like Hateful Eight then you see black bars at the top and the bottom. That is supposed to happen. That is what would automatically happen with any home video projector. But you have a business projector, and its putting white where you want black.

Menu. Owner’s Manual. Its in there somewhere.
I checked the owner's manual and nothing is there. Please check the link below to see the picutre.

I roughly measured the screen size and it looks like a 4:3 ratio screen.   The NEC LT380 is also a 4:3 projector.

The projected image is a 16:9 image, so I'm guessing your bluray or source device is outputting a 16:9 signal and the projector is only showing that aspect ratio.

If you want to fill the entire screen, you will need to look for a really old DVD movie that was filmed and produced in the old 4:3 format.  They are extremely rare, but it is possible.

For the white space on the top/bottom, you will just have to live with that.  In your case, it is an extreme amount of whitespace because your screen is a 4:3 screen.  Most all home theater screens are 16:9 (which is a compromise between the square 4:3 ratio and the super wide 2.39:1 ratio.
I wanted to use it but looks like I have to buy a new one.  Thanks for all your advise and help.Stay Safe.
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I also had a projector that was not designed for watching movies. Therefore, I read about models that have passive 3D technology and high resolution. These are the most suitable projectors for watching movies.