Quizzes & Puzzles38 mins ago
Light projection
4 Answers
Does anyone know how to project a red cross onto a black background i.e. how this is done and what colour filters you would use?
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Best Answer
No best answer has yet been selected by Onejez. Once a best answer has been selected, it will be shown here.
For more on marking an answer as the "Best Answer", please visit our FAQ.If it's a true black background, what you propose is impossible. The definition of a black surface is one which absorbs all visible light. So,no matter what you project onto it, it won't be reflected back.
There may be alternative solutions if you can change the colour of the background. (Please post again and we'll try to help you out). But if the background is black, no light can reflect from it.
Chris
There may be alternative solutions if you can change the colour of the background. (Please post again and we'll try to help you out). But if the background is black, no light can reflect from it.
Chris
As Buenchico says, projecting onto a black background won't yield very good results. Think about the last time you went to the cinema and there was a black screen.
To project a red cross using white light you will need a red filter and a cross shape cut out from either card or thin metal, although as Mortartube says it depends upon the type of projector you are using.
To project a red cross using white light you will need a red filter and a cross shape cut out from either card or thin metal, although as Mortartube says it depends upon the type of projector you are using.