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مبادئ الإضاءة ..
الإضاءة الداخلية ..
معدات الإنارة
LIGHTING EQUIPMENT
TUNGSTEN LAMPS . All the tungsten lamps used for photography are basically the same . A fine coil of tungsten wire is sealed into a glass bulb containing nitrogen gas . A current of electricity is caused to pass through this coil of wire , heating it white hot and this incandescent wire emits light . While the basic construction of tungsten filament lamps is the same , the lamps themselves differ in a number of rather important respects insofar as the photographer is concerned . We will , therefore , devote some time to their discussion .
The standard tungsten filament lamp as used for general lighting purposes , either in the home or for industrial purposes , comes in a wide variety of sizes and shapes , and any of these can be used for black - and - white photography . Where they are used in commercial studios , they are used in the higher wattages , generally from 200 watts to 500 watts , although occasionally where only a small amount of light is needed for balancing a tiny shadow area or increasing the illumination only slightly on a background , 100 watt lamps may be employed . The student who works at home with smaller film sizes and , therefore , faster lenses can generally get by very nicely with 100 watt lamps in an emergency when photographing still life or table top subjects . In such subjects , the camera is on a tripod , so long exposures present no difficulties . Generally speaking , however , for such use photoflood lamps are preferable , and these will be discussed a little later .
Ordinary tungsten filament lamps produce a rather yellow light . During evening hours when no daylight is present , this yellowish light looks perfectly white and is quite satisfactory for general illumination . However , color films do not have the ability to compensate for off - color lighting and ordinary tungsten lamps will produce abnormally yellowish or reddish pictures . To offset this situation , lamp manufacturers have developed a special lamp for shooting in the studio with color film . This lamp operates the filament at a higher temperature so that the filament emits a more neutral white . The temperature used in these lamps is 3200 degrees Kelvin ( abbreviated to 3200 ° K. )
The subject of color temperature will be discussed in a later Assignment dealing with color photography , so we won't go into any more detail at this time . Because the 3200 ° K. lamps operate at a higher temperature , they also operate more efficiently so that more total light is emitted per watt . For this reason , a good many photographers use 3200 ° K. lamps for black - and - white as well as for color photography .
The type of indoor color film which is balanced in its color response to match 3200 ° K. illumination is known as type B film , and has become the generally accepted indoor film for all professional purposes .
THE PHOTOFLOOD LAMP . There is still another type of tungsten lamp which was developed primarily for the amateur , and this lamp is known by the general . term " photoflood " lamp . In the photoflood lamp ( some typical examples of each are shown in Figure 24 ) , the filament is operated at 3400 ° K. This gives a whiter white than the 3200 ° K. lamps and a much higher efficiency - in other words , a much greater output of light per watt of electric power . However , at this high temperature the tungsten is heated to very near its boiling point so that lamp life is quite low . The No. 1 photoflood , which is the smallest and the one generally used by the amateur , puts out almost as much light as a standard tungsten filament lamp of 750 watts , yet it is only the size of a 100 watt lamp and actually consumes 250 watts . Because of its high operating temperature , the photoflood lamp has a very short life ranging from an average of two hours for the No. 1 photoflood to six hours for the No. 4 photoflood .
Figure 24 Three typical photoflood lamps used in taking photographs .
Color film designed to work with photoflood lamps is known as type A film . Very little film of this type is available for the still photographer - it being available generally only in 8mm and 16mm motion picture film . Nevertheless , photoflood lamps are still very useful for black - and - white photography since they provide very high light output in a small package and at a low current drain so that they may be used on location or in the home where the wiring is not heavy enough to permit the use of higher wattage lamps .
A rather special form of photoflood is the Reflectorflood or Reflectorspot . These lamps have a built - in , highly efficient reflector so they need no large . external reflectors . As a result , they are quite compact and easily portable . They serve a very useful function for home photography as well as for location shooting . They come in a wide variety of sizes and wattages , as well as in the width of the beam of light they emit . The Reflectorflood projects a rather wide beam and is used for general illumination , while the Reflectorspot has a much narrower beam and can serve as spotlight at close distances . Its use in this respect , however , is limited because the size of the spot cannot be controlled or focused as it can be with conventional spotlights . Nevertheless , the student who may have to work at home or with limited equipment will find Reflectorfloods and Reflectorspots extremely useful . One of these lamps in an ordinary socket equipped with a clamp - on device ( see Figure 25 ) can be clamped onto any convenient chair , pole lamp or even a door , thus eliminating the need for an expensive collapsible stand and portable reflector .
Figure 25 A reflector flood equipped with a clamp - on device .
CONCENTRATED FILAMENT LAMPS . These lamps are primarily designed for use in such devices as spotlights and projectors . We are concerned here primarily with their use in spotlights and will disregard some of the special projection lamps with exceptionally highly concentrated filaments for use in motion picture and slide projectors .
The concentrated filament spotlight type of lamp generally operates at very close to 3200 ° K. so that any of them can be used , in an emergency , for color photography with type B film . However , it is wisest to use those specifically designed to produce 3200 ° K. light . The primary point of difference between the concentrated filament lamp and others is that the small area presented by the filament permits better focusing of the spot and , of course , the glass bulb itself is perfectly clear , which is not an essential requirement for other types of lamps .
MISCELLANEOUS EQUIPMENT . For use in photography , tungsten lamps are almost invariably housed in bold shaped reflectors or other housing such as is common with focusing spotlights . This provides more illumination and gives the photographer a great deal of control over his light . As in every other item of equipment the photographer may use , reflectors come in a wide variety of sizes and shapes to meet all possible requirements . A highly portable and relatively low priced reflector on a collapsible stand is best for location photography where . portability is of first importance . Such lights are shown in Figure 26. The student photographer who must work at home and limit himself in other ways will probably use such portable lights for all of his shooting . The smaller sizes will take photofloods nicely and will give him all of the light he will need .
Figure 26 Flood lamp equipped with a general purpose reflector and a collapsible stand .
The commercial photographic studio will find it necessary to use larger and more powerful lights , since these are necessary to cover larger sets . Such studio lights need not be portable and they are , therefore , built to last with heavy cast iron bases to offer firm support and long useful life . Commercial lighting equipment of this kind is shown in Figure 27 .
Spotlights of the conventional kind are generally restricted to the studio , since they are necessarily large and heavy . However , for location shooting , Reflectorspots may often be used with considerable effect . Figures 28A , B , and C show typical studio spotlights . Their beams can be focused so as to cover small or large areas . These are extremely useful for large sets where the area to be spotlighted is at quite a distance from the source of illumination . However , for more precise spotlighting , one of the accessories described in the following paragraphs will be useful .
Figure 27 Commercial lighting equipment comes in many forms .
LIGHTING CONTROL ACCESSORIES . There are a number of lighting accessories which permit the photographer still further to increase his control over his lighting . We will discuss here only those in more common use .
The first of these is called a barndoor for obvious reasons ( see Figure 29 ) . It consists of a small metal screen which can be clamped to the side of a reflector or spotlight in such a way that it can be swung in front of the beam of light to control its width . Barndoors are extremely useful devices for controlling the width of a projected beam of light either from a spot or a flood . Since it is quite close to the light , it does not cast a sharp shadow so that its use is not too obvious . However , where a sharply defined area must be shaded , any dark colored card or board can be clamped to an upright and moved around until its shadow . exactly covers the desired area .
Figure 28 Setting up a studio spotlight .
Figure 28A Shown here is a studio spot light . At the front is a fresnel condenser lens . The lamp inside can be moved toward or away from this lens to focus the light .
Figure 28B A stand built for maximum versatility . With a stand such as this , a light can be placed anywhere .
If the beam of a spotlight is too broad or if its outline must be defined more sharply , a card or sheet of metal with a hole at its center can be held in front of the spotlight . The size of the hole and its distance from the spotlight will determine the size of the projected circle of light . For the commercial studio , however , it is generally better to use a snoot ( see Figure 30 ) . This consists of a metal tube which can be mounted in front of the spotlight and it projects a more sharply defined circle than does a simple card with a hole in it .
Figure 29 " Barndoors " such as these are used to control the width of the beam of light .
Figure 30 " Snoots " are used . to concentrate the spotlight into a narrow beam .
A diffusing screen is another very useful tool for the control of lighting . Tungsten lamps are all relatively small sources of light , and a small source of light always produces a sharp clearly defined shadow . In certain types of photography , this type of shadow may be desirable , but for average use , a more diffused shadow is to be preferred .
There are a number of ways in which the desired diffusion can be obtained For example , when a lamp is placed in a reflector of proper design , the entire front area of the reflector becomes the light source and this , of course , affords a certain amount of diffusion . The larger the reflector , therefore , the greater the degree of diffusion of the light source . That is one reason why the larger reflectors are more desirable for studio work where portability is not too much of a problem . However , when this is not enough diffusion , as is often the case for portrait work , a larger semi - transparent screen , such as a sheet of tissue paper or draftsman's tracing cloth can be placed in front of the light . Since the light spreads as it leaves the reflector , the spot on the diffusing screen is larger and the lighting is more diffused .
For smaller reflectors , in which the lamp itself contributes most of the lighting , sufficient diffusion can often be obtained simply by mounting a diffusing screen directly onto the reflector . Such screens may be purchased for that purpose . They are generally made of spunglass so that their proximity to the lamp . itself will do no harm . Tissue paper or cloth at this close distance may char or burn . A simple diffusing screen which can be attached to a portable reflector is shown in Figure 31 .
If a great deal of diffusion is wanted to provide a very soft almost shadowless lighting , it can be done by aiming the light not at the subject but at a large white screen or portable background . The screen then becomes the source of light and if it is large enough , the light will be diffused as much as , let us say , the light from a slightly overcast sky . This type of lighting can be very useful where a great deal of softness and delicate modeling is needed in a portrait . It can also be used for photographing very highly polished or shiny objects . The subject of illuminating such objects properly will be discussed in a later Assignment .
A type of diffuser which has gained a great deal of popularity recently is the umbrella type . As its name implies , this is quite similar to an ordinary umbrella , so that it can be folded compactly so that it is extremely portable . Although originally designed as a portable diffuser , its extreme usefulness has made it very popular for studio use as well . Umbrella diffusers are of two types . In one , the material is opaque , being black on the outside and white on the inside . It is used , therefore , primarily as a reflector . The other type . a translucent cloth , so that it can be used either as a reflector or as an ordinary diffusion screen . Figure 32 shows an umbrella of this kind fitted to a studio type electronic flash unit .
Figure 31 Spun glass diffuser attached to lamp reflector
Figure 32 Umbrella diffuser fitted to studio type electronic flash unit .
We now have our basic lighting equipment . With this equipment , any competent photographer can light practically any subject in practically any manner to produce practically any desired effect . There are , of course , some highly specialized items we have not discussed here , but the great majority of successful photographers use only the equipment we have talked about . Of course , they may have quite a number of lights of different sizes and power , so they can flood a complete studio set with high intensity light , or they can concen trate their light on a very small area for taking a tiny object at close - up , but basically they use nothing which has not been described here .
مبادئ الإضاءة ..
الإضاءة الداخلية ..
معدات الإنارة
LIGHTING EQUIPMENT
TUNGSTEN LAMPS . All the tungsten lamps used for photography are basically the same . A fine coil of tungsten wire is sealed into a glass bulb containing nitrogen gas . A current of electricity is caused to pass through this coil of wire , heating it white hot and this incandescent wire emits light . While the basic construction of tungsten filament lamps is the same , the lamps themselves differ in a number of rather important respects insofar as the photographer is concerned . We will , therefore , devote some time to their discussion .
The standard tungsten filament lamp as used for general lighting purposes , either in the home or for industrial purposes , comes in a wide variety of sizes and shapes , and any of these can be used for black - and - white photography . Where they are used in commercial studios , they are used in the higher wattages , generally from 200 watts to 500 watts , although occasionally where only a small amount of light is needed for balancing a tiny shadow area or increasing the illumination only slightly on a background , 100 watt lamps may be employed . The student who works at home with smaller film sizes and , therefore , faster lenses can generally get by very nicely with 100 watt lamps in an emergency when photographing still life or table top subjects . In such subjects , the camera is on a tripod , so long exposures present no difficulties . Generally speaking , however , for such use photoflood lamps are preferable , and these will be discussed a little later .
Ordinary tungsten filament lamps produce a rather yellow light . During evening hours when no daylight is present , this yellowish light looks perfectly white and is quite satisfactory for general illumination . However , color films do not have the ability to compensate for off - color lighting and ordinary tungsten lamps will produce abnormally yellowish or reddish pictures . To offset this situation , lamp manufacturers have developed a special lamp for shooting in the studio with color film . This lamp operates the filament at a higher temperature so that the filament emits a more neutral white . The temperature used in these lamps is 3200 degrees Kelvin ( abbreviated to 3200 ° K. )
The subject of color temperature will be discussed in a later Assignment dealing with color photography , so we won't go into any more detail at this time . Because the 3200 ° K. lamps operate at a higher temperature , they also operate more efficiently so that more total light is emitted per watt . For this reason , a good many photographers use 3200 ° K. lamps for black - and - white as well as for color photography .
The type of indoor color film which is balanced in its color response to match 3200 ° K. illumination is known as type B film , and has become the generally accepted indoor film for all professional purposes .
THE PHOTOFLOOD LAMP . There is still another type of tungsten lamp which was developed primarily for the amateur , and this lamp is known by the general . term " photoflood " lamp . In the photoflood lamp ( some typical examples of each are shown in Figure 24 ) , the filament is operated at 3400 ° K. This gives a whiter white than the 3200 ° K. lamps and a much higher efficiency - in other words , a much greater output of light per watt of electric power . However , at this high temperature the tungsten is heated to very near its boiling point so that lamp life is quite low . The No. 1 photoflood , which is the smallest and the one generally used by the amateur , puts out almost as much light as a standard tungsten filament lamp of 750 watts , yet it is only the size of a 100 watt lamp and actually consumes 250 watts . Because of its high operating temperature , the photoflood lamp has a very short life ranging from an average of two hours for the No. 1 photoflood to six hours for the No. 4 photoflood .
Figure 24 Three typical photoflood lamps used in taking photographs .
Color film designed to work with photoflood lamps is known as type A film . Very little film of this type is available for the still photographer - it being available generally only in 8mm and 16mm motion picture film . Nevertheless , photoflood lamps are still very useful for black - and - white photography since they provide very high light output in a small package and at a low current drain so that they may be used on location or in the home where the wiring is not heavy enough to permit the use of higher wattage lamps .
A rather special form of photoflood is the Reflectorflood or Reflectorspot . These lamps have a built - in , highly efficient reflector so they need no large . external reflectors . As a result , they are quite compact and easily portable . They serve a very useful function for home photography as well as for location shooting . They come in a wide variety of sizes and wattages , as well as in the width of the beam of light they emit . The Reflectorflood projects a rather wide beam and is used for general illumination , while the Reflectorspot has a much narrower beam and can serve as spotlight at close distances . Its use in this respect , however , is limited because the size of the spot cannot be controlled or focused as it can be with conventional spotlights . Nevertheless , the student who may have to work at home or with limited equipment will find Reflectorfloods and Reflectorspots extremely useful . One of these lamps in an ordinary socket equipped with a clamp - on device ( see Figure 25 ) can be clamped onto any convenient chair , pole lamp or even a door , thus eliminating the need for an expensive collapsible stand and portable reflector .
Figure 25 A reflector flood equipped with a clamp - on device .
CONCENTRATED FILAMENT LAMPS . These lamps are primarily designed for use in such devices as spotlights and projectors . We are concerned here primarily with their use in spotlights and will disregard some of the special projection lamps with exceptionally highly concentrated filaments for use in motion picture and slide projectors .
The concentrated filament spotlight type of lamp generally operates at very close to 3200 ° K. so that any of them can be used , in an emergency , for color photography with type B film . However , it is wisest to use those specifically designed to produce 3200 ° K. light . The primary point of difference between the concentrated filament lamp and others is that the small area presented by the filament permits better focusing of the spot and , of course , the glass bulb itself is perfectly clear , which is not an essential requirement for other types of lamps .
MISCELLANEOUS EQUIPMENT . For use in photography , tungsten lamps are almost invariably housed in bold shaped reflectors or other housing such as is common with focusing spotlights . This provides more illumination and gives the photographer a great deal of control over his light . As in every other item of equipment the photographer may use , reflectors come in a wide variety of sizes and shapes to meet all possible requirements . A highly portable and relatively low priced reflector on a collapsible stand is best for location photography where . portability is of first importance . Such lights are shown in Figure 26. The student photographer who must work at home and limit himself in other ways will probably use such portable lights for all of his shooting . The smaller sizes will take photofloods nicely and will give him all of the light he will need .
Figure 26 Flood lamp equipped with a general purpose reflector and a collapsible stand .
The commercial photographic studio will find it necessary to use larger and more powerful lights , since these are necessary to cover larger sets . Such studio lights need not be portable and they are , therefore , built to last with heavy cast iron bases to offer firm support and long useful life . Commercial lighting equipment of this kind is shown in Figure 27 .
Spotlights of the conventional kind are generally restricted to the studio , since they are necessarily large and heavy . However , for location shooting , Reflectorspots may often be used with considerable effect . Figures 28A , B , and C show typical studio spotlights . Their beams can be focused so as to cover small or large areas . These are extremely useful for large sets where the area to be spotlighted is at quite a distance from the source of illumination . However , for more precise spotlighting , one of the accessories described in the following paragraphs will be useful .
Figure 27 Commercial lighting equipment comes in many forms .
LIGHTING CONTROL ACCESSORIES . There are a number of lighting accessories which permit the photographer still further to increase his control over his lighting . We will discuss here only those in more common use .
The first of these is called a barndoor for obvious reasons ( see Figure 29 ) . It consists of a small metal screen which can be clamped to the side of a reflector or spotlight in such a way that it can be swung in front of the beam of light to control its width . Barndoors are extremely useful devices for controlling the width of a projected beam of light either from a spot or a flood . Since it is quite close to the light , it does not cast a sharp shadow so that its use is not too obvious . However , where a sharply defined area must be shaded , any dark colored card or board can be clamped to an upright and moved around until its shadow . exactly covers the desired area .
Figure 28 Setting up a studio spotlight .
Figure 28A Shown here is a studio spot light . At the front is a fresnel condenser lens . The lamp inside can be moved toward or away from this lens to focus the light .
Figure 28B A stand built for maximum versatility . With a stand such as this , a light can be placed anywhere .
If the beam of a spotlight is too broad or if its outline must be defined more sharply , a card or sheet of metal with a hole at its center can be held in front of the spotlight . The size of the hole and its distance from the spotlight will determine the size of the projected circle of light . For the commercial studio , however , it is generally better to use a snoot ( see Figure 30 ) . This consists of a metal tube which can be mounted in front of the spotlight and it projects a more sharply defined circle than does a simple card with a hole in it .
Figure 29 " Barndoors " such as these are used to control the width of the beam of light .
Figure 30 " Snoots " are used . to concentrate the spotlight into a narrow beam .
A diffusing screen is another very useful tool for the control of lighting . Tungsten lamps are all relatively small sources of light , and a small source of light always produces a sharp clearly defined shadow . In certain types of photography , this type of shadow may be desirable , but for average use , a more diffused shadow is to be preferred .
There are a number of ways in which the desired diffusion can be obtained For example , when a lamp is placed in a reflector of proper design , the entire front area of the reflector becomes the light source and this , of course , affords a certain amount of diffusion . The larger the reflector , therefore , the greater the degree of diffusion of the light source . That is one reason why the larger reflectors are more desirable for studio work where portability is not too much of a problem . However , when this is not enough diffusion , as is often the case for portrait work , a larger semi - transparent screen , such as a sheet of tissue paper or draftsman's tracing cloth can be placed in front of the light . Since the light spreads as it leaves the reflector , the spot on the diffusing screen is larger and the lighting is more diffused .
For smaller reflectors , in which the lamp itself contributes most of the lighting , sufficient diffusion can often be obtained simply by mounting a diffusing screen directly onto the reflector . Such screens may be purchased for that purpose . They are generally made of spunglass so that their proximity to the lamp . itself will do no harm . Tissue paper or cloth at this close distance may char or burn . A simple diffusing screen which can be attached to a portable reflector is shown in Figure 31 .
If a great deal of diffusion is wanted to provide a very soft almost shadowless lighting , it can be done by aiming the light not at the subject but at a large white screen or portable background . The screen then becomes the source of light and if it is large enough , the light will be diffused as much as , let us say , the light from a slightly overcast sky . This type of lighting can be very useful where a great deal of softness and delicate modeling is needed in a portrait . It can also be used for photographing very highly polished or shiny objects . The subject of illuminating such objects properly will be discussed in a later Assignment .
A type of diffuser which has gained a great deal of popularity recently is the umbrella type . As its name implies , this is quite similar to an ordinary umbrella , so that it can be folded compactly so that it is extremely portable . Although originally designed as a portable diffuser , its extreme usefulness has made it very popular for studio use as well . Umbrella diffusers are of two types . In one , the material is opaque , being black on the outside and white on the inside . It is used , therefore , primarily as a reflector . The other type . a translucent cloth , so that it can be used either as a reflector or as an ordinary diffusion screen . Figure 32 shows an umbrella of this kind fitted to a studio type electronic flash unit .
Figure 31 Spun glass diffuser attached to lamp reflector
Figure 32 Umbrella diffuser fitted to studio type electronic flash unit .
We now have our basic lighting equipment . With this equipment , any competent photographer can light practically any subject in practically any manner to produce practically any desired effect . There are , of course , some highly specialized items we have not discussed here , but the great majority of successful photographers use only the equipment we have talked about . Of course , they may have quite a number of lights of different sizes and power , so they can flood a complete studio set with high intensity light , or they can concen trate their light on a very small area for taking a tiny object at close - up , but basically they use nothing which has not been described here .
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