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View Full Version : Chemicals visible under certain conditions?


theparkranger24
Jul 30, 2013, 06:29 PM
Okay, so I know that there are some chemicals that glow when shown under a blacklight or UV light. I am curious if there are any chemicals that are visible under other conditions?
Such as looking at a chemical through certain filters? (such as different types of tints or whatever of glass or plastic)
What chemicals and filters might there be that meet this criteria?

ebaines
Jul 31, 2013, 01:34 PM
The function of filter is to transmit only a narrow band of light, so unlike your first example of illuminating an object with infrared or ultrviolet light to excite it and make it glow, using a filter has no effect on the object itself. But they are useful for is filtering out the "noise" of wavelengths of light that you are not interested in observing, and that might otherwise overwhelm the specific wavelength or color that you want to observe. I can't think of any chemistry applications for this, but in astronomy filters are commonly used to enhance the detail of an imagine of a star or planet in a telescope. For example if you've seen photos of large solar flares where you see an arm of plasma arcing above the solar surface that image is taken using a hydrogen-alpha filter, whose job is to filter out all wavelengths except the wavelength of light that corresponds to a particular electron transition of a hydrogen item. Without that filter the extreme intensity of white light from the solar corona washes out the flare that you're trying to see. Another example is the ghostly green color you sometimes see in photos of nebulae - that's from using an oxygen filter, which lets through light associated with ionized oxygen atoms.