Hi to all newbies i would really like to share my knowledge to you all about lights and since we photographers depend on lights so i think its best if i share it with u guys..(i hope the admins and mods will approve)
What is light?
light is that narrow bend of electromagnetic radiation to which the human eye is sensitive. there are no exact boundaries to the range of visible light, as individuals differ. technically our eyes are receptive to a range of wavelengths of light between 400-700 nanometres(nm) . (a nanometer is one millionth of a millimeter.)
There is a radiant energy above and below the limits of the visible spectrum: above violet is described as ultraviolet, below red as infrared. Imaging systems (film and digital) can pick up these 'colours' and fold them back into visibility.
Light has three physical properties that interest the photographer - amplitude (or intensity) , the wavelength or frequency and the angle of vibration (or polarization) . in laymans term , intensity can be thought of as the brightness of light and the frequency or wavelength determines its color. we can barely perceive changes in palorization but this phenomenon can be manipulated photographically with polarizing filters.
Light travels in straight lines , which is why we get shadows , it is also reflected off a mirror or silvered surface at the reverse angle to which it falls , like a billiard ball hitting a cushion. knowledge of these simple facts allows photographers to shape light using cutters and reflectors , light can also be bent (refrected) , which mean we can design lenses to focus image
Without lights , there are no colors, A green pepper only looks green if the corresponding wavelengths (colours) are present in the illuminating light . in orange light that contains no green , a green pepper will look grey and colourless..
We have a photographic definition of the light that contains all the colours and is therefore white - 'daylight' - but photographers use this term in a precise way and it is not quite what you may think. All out 'white' light comes from radiating energy sources - The Sun, metal filaments heated by electric current (light bulbs) the light burst from an electric arc (flash gun). There is some implied connection with heat, Photographers use the idea of colour temperature - a spectrum derived from looking at the colours of abject as they heat up - to describe a precise colour of a light source, be it blue-white or yellow-white , understanding colour temperature and how to control or adjust it is vital to film and digital camera....
Thats all folks and if the admins or mods approve it i will post again..Thanks..