Hey guys its been a while.
I have put together a projector by using an old ohp and a seven inch lcd. The screen is white blackout cloth.
The problem i am having is there is a white haze over the picture blacks are grey etc.
Ive adjusted all the settings on the lcd itself no effect, so im starting to think its my screen. Is there a cheap fix to this????
Thanks
I have put together a projector by using an old ohp and a seven inch lcd. The screen is white blackout cloth.
The problem i am having is there is a white haze over the picture blacks are grey etc.
Ive adjusted all the settings on the lcd itself no effect, so im starting to think its my screen. Is there a cheap fix to this????
Thanks
If you have your brightness turned all the way dark, and it is still too light. You can do one of two things. Go get some sheets like makey said, maybe a low-e glass will work the best. Or, you can try turning all your colors up, if you turn them together, it should keep the color the same? good luck
Tilt the lcd and the projection lens,so you still have good focus,in the horizontal plane,one side or the other depenting on how the lcd is positioned .This should work.What happens is that the low quality lcd screen has no strong backlight etc and polarizing filters are placed in such an angle that do not block a lot of light,so the screen is brighter but with bad contrast,which in these type of lcd screens often happens.
Have a look at the drawing i uploaded,probably it will explain things better than my poor english.
Have a look at the drawing i uploaded,probably it will explain things better than my poor english.
Attachments
1. Let the opposite side of the LCD panel (the side which face the backlight before you dismantled the lcd) face the projecting lens will solve the problem markedly, but you need to remove the reflecting mirror to get correct image on the screen.
2. Use a gray-colored screen. A gray-colored screen will raise the contrast markedly, and darken the black area of the picture. Or you can use a silver-colored material as your screen so you gain the contrast without losing brightness.
By using the combination of the above mentioned 2 modifications, I think more than 90% of the haze over the picture will disappear.
2. Use a gray-colored screen. A gray-colored screen will raise the contrast markedly, and darken the black area of the picture. Or you can use a silver-colored material as your screen so you gain the contrast without losing brightness.
By using the combination of the above mentioned 2 modifications, I think more than 90% of the haze over the picture will disappear.
There are a lot of grey wallpaper,grey curtain in China store. The metallic grey like the color of the steel works very good. I am using a steel grey wallpaper, and I will never use any white screen or white wall anymore.
I think aluminum foil covered by tracing paper (the translucent paper) will be much better, but too bright for the light bulb you are using.
I think aluminum foil covered by tracing paper (the translucent paper) will be much better, but too bright for the light bulb you are using.
I think you can tweak it to look better, but the little LCD probably just has a low contrast overall, meaning you will only be able to get so much. Using grey screens will darken the whole picture, and using bright screens will brighten the whole picture, I think your contrast will stay relatively the same.
stelleg151 said:
I think whether the contrast stay relatively the same depends on how the grey screens darken the picture.
1). If the grey screen darken the picture only by subtracting certain amount of brightness evenly from the whole area of the projected picture, then the grey screen works very effectively to darken the black area.
2). If the grey screen darken the picture only by dividing the brightness of the whole picture by a certain coefficient ( >1), then the contrast is lower than( not equal to) using a white screen.
From my tests, I think the 1) effect is dominant if the grey screen is silverish. You need to test many to find the best one.
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