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Thread: OPTICS: Generating Parallel (hard) Light from Diffused Light

  1. #1 OPTICS: Generating Parallel (hard) Light from Diffused Light 
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    I'm trying to find some information regarding the opposite of soft lighting. I believe the term is parallel light, or hard light.... But Google doesn't respond very well to my search terms-- with respect to the information that I am seeking.


    To put it simply, I am trying to create a light source where the shadow of any object in front of the source will be hard and sharp (like sunlight shadows), rather than soft and diffused (like fluorescent light shadows).

    I prefer to use a soft light source, such as a fluorescent bulb, due to their low cost, even light distribution, and UV properties; However, I'm at a loss to find a source of information regarding the construction of such a lighting device... Any help to be had here? Some terminology correction would be great, some pointers on a common lens apparatus would be ideal. Anything at all would be appreciated!


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  3. #2  
    Administrator KALSTER's Avatar
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    Have you searched for fresnel lights? :wink:


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  4. #3  
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    The normal way is to use a small, intense source of light. Then you send the light through a small aperture and use a simple convex lens to obtain parallel rays.

    It can be done, I suppose, using a fluorescent light, but your resultant beam will use only a small fraction of the available light and it will be rather weak. Fluorescent lighting is not a good source for these kind of experiments.

    If you use quality detection equipment a weak beam of light may still be adequate.

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  5. #4  
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    thanks for the replies you guys. sorry I havnt responded- been really busy with work.

    Anyhow, I'm working on a projector for photo-lithographic processing of photo-emulsion film trough a mask; So weak uv is okay, i'll just have to bump the exposure time significantly.. which is okay if I can get really tight tolerance on the sharpness of the projected mask.


    Thanks again
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