R-Type lamps are found in sizes varying from about 2.5" in diameter to 6.5"+ diameter. They are for in door use only and are found in several styles of
border lights (r-38 and R-40 primarily). They
throw a nice punch of flood light out in a more concentrated
pattern than an A type lamp and can come in wattages from 60 to about 500 watts.
PAR- Type lamps use a
Parabolic Alumanized
Reflector system with a glass
lens on the front that usually varies the field diameter. PARS are available from PAR-20 to PAR-64 and vary from around 50 watts to 2 kilowatts. PARS are a heavy duty version of the R type lamp and have an "axis" of light because of
filament geometry, usually
PAR type lamps have a beam that is twice as long as it is wide. The beam spreads are as follows (VNSP, NSP, MFL, and WFL). The
base is either a
mogul screw
base or a
mogul end prong
base depending on what
fixture the lamp is being used in.
MR- type lamps are typically low
voltage (12v-82v) but 120v versions are available. They are used to accent things such as art work. They are also the primary type of lamp used in several different follow spots (
Altman Comet). The
reflector on an MR lamp is design to absorb UV and IR radiation and reflect visible light. The field angles are any where from about 8° to 50°. The sizes vary from anything as small as an MR-8 (1" diam) to a standard MR-16 (2" diam) or sometimes even larger, but, the MR-16 is still the more standard of the sizes available.
I know nothing about K-type lamps, so maybe ship can fill you in on that