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النسخ وإسقاط الشرائح .. المرشد خطوة بخطوة للتصوير الفوتوغرافي
Copying and slide projection
It is useful to be able to photograph and copy images , either pictures , drawings or text . By copying you can achieve special effects such as converting an image to line ( see p . 131 ) or montage . The most import- ant factors for success are even lighting , and a camera position absolutely square - on to your original . For copying continuous tones use general purpose fine grain black and white film ; for color copying use film appropriate to the light source . The best way to measure exposure is to place a mid- gray card over the original and take the reading from this . Remember to allow for extension tubes or bellows if your meter does not measure through the lens .
Avoiding camera reflections
If you are copying an original which is behind glass or has a glossy surface , bright parts of the camera may reflect off the surface and record in your copy . Use a large sheet of black card , as shown above , to mask the camera , cutting a hole for the lens .
Using a copystand
You can make a copystand like the one shown above , or adapt one from an old enlarger . The stand will hold the camera steady and ensure that it is always square - on to the image . Arrange two lamps equidistant from the camera sup- port , directed at about 45 ° to the board . It is best to paint the copy board and reflective parts of the lamp supports black to reduce flare . For black and white photo- graphy 100 watt lamps are adequate , but for color work the reflectors must be large enough to accept 3200 ° K type lamps .
Checking evenness
Your lighting should be as even as possible . One way to check this is by placing a pencil or ruler at the center of the original and comparing the darkness of the two shadows formed . If these are obviously different , alter the rela- tive distances of your lamps . Avoid having lights too close this will give a patchy effect .
Slide projection
The best way to view color slides is to use a projector , but the quality of your projector and conditions of viewing can greatly affect your results . Strong illumination makes the most of image colors and increases apparent sharpness , but projectors with efficient cooling systems for strong lamps and good wide aperture lenses are expensive . If you only have a small projector keep to a small image which will then be well illuminated .
All projectors heat - up color slides , to a greater or lesser extent . If the film is held in a simple cardboard mount it will bow slightly during projection so that the center or edges appear out - of - focus . Glass faced plastic mounts ( see p . 176 ) avoid this problem .
Types of projector
Hand - operated projector
above , uses a sliding hand- A simple projector , like the one operated carrier . This takes two slides ; while one is projected the other can be changed .
Magazine projector
The more elaborate machine , above , holds a magazine of up to 50 slides . The slide is changed auto- matically by remote control .
Setting up projection
When you project slides it is essential to black - out the room properly . Even a small amount of extraneous light will dilute your image blacks to dark gray , degrade contrast , and de - saturate color . If you do not have a projection screen use a flat mat white wall , or large card . You can buy screens with highly reflective beaded sur- faces which give a more brilliant image than a mat white . They are very directional and your audience should sit near the projector beam .
Beaded white screen viewing angle
Mat white screen viewing angle
Rotary magazine projector
Projectors with rotary magazines allow longer slide programs to be shown without a break . In the model above , up to 80 slides are stored in a dust - proof magazine . Each slide is automatically lowered , projected , and replaced in turn .
Copying and slide projection
It is useful to be able to photograph and copy images , either pictures , drawings or text . By copying you can achieve special effects such as converting an image to line ( see p . 131 ) or montage . The most import- ant factors for success are even lighting , and a camera position absolutely square - on to your original . For copying continuous tones use general purpose fine grain black and white film ; for color copying use film appropriate to the light source . The best way to measure exposure is to place a mid- gray card over the original and take the reading from this . Remember to allow for extension tubes or bellows if your meter does not measure through the lens .
Avoiding camera reflections
If you are copying an original which is behind glass or has a glossy surface , bright parts of the camera may reflect off the surface and record in your copy . Use a large sheet of black card , as shown above , to mask the camera , cutting a hole for the lens .
Using a copystand
You can make a copystand like the one shown above , or adapt one from an old enlarger . The stand will hold the camera steady and ensure that it is always square - on to the image . Arrange two lamps equidistant from the camera sup- port , directed at about 45 ° to the board . It is best to paint the copy board and reflective parts of the lamp supports black to reduce flare . For black and white photo- graphy 100 watt lamps are adequate , but for color work the reflectors must be large enough to accept 3200 ° K type lamps .
Checking evenness
Your lighting should be as even as possible . One way to check this is by placing a pencil or ruler at the center of the original and comparing the darkness of the two shadows formed . If these are obviously different , alter the rela- tive distances of your lamps . Avoid having lights too close this will give a patchy effect .
Slide projection
The best way to view color slides is to use a projector , but the quality of your projector and conditions of viewing can greatly affect your results . Strong illumination makes the most of image colors and increases apparent sharpness , but projectors with efficient cooling systems for strong lamps and good wide aperture lenses are expensive . If you only have a small projector keep to a small image which will then be well illuminated .
All projectors heat - up color slides , to a greater or lesser extent . If the film is held in a simple cardboard mount it will bow slightly during projection so that the center or edges appear out - of - focus . Glass faced plastic mounts ( see p . 176 ) avoid this problem .
Types of projector
Hand - operated projector
above , uses a sliding hand- A simple projector , like the one operated carrier . This takes two slides ; while one is projected the other can be changed .
Magazine projector
The more elaborate machine , above , holds a magazine of up to 50 slides . The slide is changed auto- matically by remote control .
Setting up projection
When you project slides it is essential to black - out the room properly . Even a small amount of extraneous light will dilute your image blacks to dark gray , degrade contrast , and de - saturate color . If you do not have a projection screen use a flat mat white wall , or large card . You can buy screens with highly reflective beaded sur- faces which give a more brilliant image than a mat white . They are very directional and your audience should sit near the projector beam .
Beaded white screen viewing angle
Mat white screen viewing angle
Rotary magazine projector
Projectors with rotary magazines allow longer slide programs to be shown without a break . In the model above , up to 80 slides are stored in a dust - proof magazine . Each slide is automatically lowered , projected , and replaced in turn .
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