تويت
مصابيح البخار .. مصدر الضوء .. كيفية التقاط وتطوير الصور الملونة
VAPOUR LAMPS
Vapour discharge lighting , used almost exclusively in large outdoor areas such as streets , stadiums and factory complexes , works on a similar principle to fluorescent lighting , but the lamps are uncoated . There are three main types : sodium vapour , mercury vapour and multi - vapour . Only the last of these is in any way easy to work with , so the trick is being able to identify which is which .
the lamps are first switched on . It is popular for street lighting and for flood- lighting major public buildings . The spectrum of sodium vapour light is the narrowest of all about 95 % of the light is in the yellow - green part of the spectrum and there is no filtration that you can use to make it look natural . Filters can only work with the lighting that exists , and there is just no red or blue in this kind of lamp .
Mercury vapour and multi - vapour lamps are difficult to distinguish just by looking at them . Both look more or less white , but while multi - vapour photo- graphs quite naturally , mercury vapour is in fact quite strongly blue . The clue is in where they are used . In a sports stadium , you can be fairly certain that the lamps are multi - vapour because matches are televised and the lighting has to be balanced . Elsewhere , assume it is mercury vapour . Use no filters for multi- vapour , but try a CC30 red or CC40 red with mercury lamps .
Universal holder
Gelatin holder
Lens shade
ABOVE LEFT Filter holders are attached to the lens via an adapter ring . ( The gelatin holder is used to hold thin acrylic sheets which actually act as masks rather than filters for special effects shots . ) A lens shade helps reduce undesirable flare and surface reflection .
Sodium vapour is very popular for street lighting and for floodlighting public buildings . However , it is impossible to filter out the yellow - green cast in photographs .
ABOVE The cast caused by mercury vapour lighting need not be unappealing , but if the photographer wishes to filter the cast out , either a CC30 red or CC40 red filter may be used .
VAPOUR LAMPS
Vapour discharge lighting , used almost exclusively in large outdoor areas such as streets , stadiums and factory complexes , works on a similar principle to fluorescent lighting , but the lamps are uncoated . There are three main types : sodium vapour , mercury vapour and multi - vapour . Only the last of these is in any way easy to work with , so the trick is being able to identify which is which .
the lamps are first switched on . It is popular for street lighting and for flood- lighting major public buildings . The spectrum of sodium vapour light is the narrowest of all about 95 % of the light is in the yellow - green part of the spectrum and there is no filtration that you can use to make it look natural . Filters can only work with the lighting that exists , and there is just no red or blue in this kind of lamp .
Mercury vapour and multi - vapour lamps are difficult to distinguish just by looking at them . Both look more or less white , but while multi - vapour photo- graphs quite naturally , mercury vapour is in fact quite strongly blue . The clue is in where they are used . In a sports stadium , you can be fairly certain that the lamps are multi - vapour because matches are televised and the lighting has to be balanced . Elsewhere , assume it is mercury vapour . Use no filters for multi- vapour , but try a CC30 red or CC40 red with mercury lamps .
Universal holder
Gelatin holder
Lens shade
ABOVE LEFT Filter holders are attached to the lens via an adapter ring . ( The gelatin holder is used to hold thin acrylic sheets which actually act as masks rather than filters for special effects shots . ) A lens shade helps reduce undesirable flare and surface reflection .
Sodium vapour is very popular for street lighting and for floodlighting public buildings . However , it is impossible to filter out the yellow - green cast in photographs .
ABOVE The cast caused by mercury vapour lighting need not be unappealing , but if the photographer wishes to filter the cast out , either a CC30 red or CC40 red filter may be used .
تعليق