Basic Photography Course

Figure 8-3.Lights positioned at a 45-degree angle.

original without moving the camera or the original.
When the camera is not designed with a rising, falling,

and sliding front, the camera or original must be moved
to align the original with the optical axis of the lens.

LIGHTING THE ORIGINAL

One of the most important elements in copying is

proper, even illumination of the original. Originals that

are not properly and evenly lighted yield negatives with
uneven density, which are hard to print. This is true
whether the original is illuminated by daylight or
artificial light. Uneven illumination can be caused by
improper placement of artificial lights in relation to the
copyboard or by improper placement of the original in
daylight.

Artificial lights are normally placed on two sides of

the copyboard. A 45-degree angle is recommended for
general use (fig. 8-3). At this angle, a minimum of
unwanted reflections from the surface of the original
occurs. However, depending on the type of surface of

the original, the best angle for the lights may change.

For example, an original artwork may have brush
strokes that produce reflections. These reflections may
be reduced somewhat by placing the lights at an angle
greater or lesser than 45-degrees.

Do not position artificial lights too close to the

copyboard. The circles of illumination will not cover the
original completely. Movable lights should not be
positioned so far from the copyboard that the intensity
of the illumination falling on the original is greatly

reduced.

The evenness of illumination on an original can be

checked with an exposure meter. Do this by placing a
gray card on the original and taking a reflected light
meter reading from the card. Do not allow the shadow
of the meter or your hand to influence the reading. When

a gray card is not available, a white card (the back of a
sheet of photo paper) can be used, but you must
compensate your exposure by two f/stops. Reflected
light from the four corners and center area of the original
should read the same light values.

Daylight provides two choices of illumination:

direct sunlight and diffused daylight, such as a cloudy,
bright day or open shade. Evenness of daylight

illumination is controlled by ensuring that the original
is completely in direct sunlight or in diffused daylight,
and no shadows are cast on the original.

Although an original is uniformly illuminated over

its entire surface, apparent unevenness in illumination
may still appear in the copy if a wide-angle lens is used.
This is caused when the light transmitted through the
center of the lens is more intense than the light
transmitted near the edges of the lens. When the entire
angle of view of the wide-angle lens must be used, more
illumination to the edges of the original is needed to
compensate for the falloff of light at the edges of the
lens. This can be achieved by turning the lights slightly
toward the edges or by moving the lights close to the
edges. The amount of light increase necessary for the
edges of the original is best determined by conducting
exposure tests with the type of film being used.

Lighting control is more critical when using an

extremely high contrast film, compared to a high,

moderate, normal, or low contrast film. Uneven lighting
is more visible in a copy produced with an extremely
high contrast film because of the limited exposure
latitude of the emulsion.

8-14

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Basic Photography Course

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DOFMaster for Windows On-line Depth of Field Calculator DOFMaster for Mobile Devices On-line Depth of Field Table Hyperfocal Distance Chart Articles FAQ Recommended Books Support Contact Links Home As an Amazon Associate I earn from qualifying purchases.	contents <- previous page next page -> Figure 8-3.Lights positioned at a 45-degree angle. original without moving the camera or the original. When the camera is not designed with a rising, falling, and sliding front, the camera or original must be moved to align the original with the optical axis of the lens. LIGHTING THE ORIGINAL One of the most important elements in copying is proper, even illumination of the original. Originals that are not properly and evenly lighted yield negatives with uneven density, which are hard to print. This is true whether the original is illuminated by daylight or artificial light. Uneven illumination can be caused by improper placement of artificial lights in relation to the copyboard or by improper placement of the original in daylight. Artificial lights are normally placed on two sides of the copyboard. A 45-degree angle is recommended for general use (fig. 8-3). At this angle, a minimum of unwanted reflections from the surface of the original occurs. However, depending on the type of surface of the original, the best angle for the lights may change. For example, an original artwork may have brush strokes that produce reflections. These reflections may be reduced somewhat by placing the lights at an angle greater or lesser than 45-degrees. Do not position artificial lights too close to the copyboard. The circles of illumination will not cover the original completely. Movable lights should not be positioned so far from the copyboard that the intensity of the illumination falling on the original is greatly reduced. The evenness of illumination on an original can be checked with an exposure meter. Do this by placing a gray card on the original and taking a reflected light meter reading from the card. Do not allow the shadow of the meter or your hand to influence the reading. When a gray card is not available, a white card (the back of a sheet of photo paper) can be used, but you must compensate your exposure by two f/stops. Reflected light from the four corners and center area of the original should read the same light values. Daylight provides two choices of illumination: direct sunlight and diffused daylight, such as a cloudy, bright day or open shade. Evenness of daylight illumination is controlled by ensuring that the original is completely in direct sunlight or in diffused daylight, and no shadows are cast on the original. Although an original is uniformly illuminated over its entire surface, apparent unevenness in illumination may still appear in the copy if a wide-angle lens is used. This is caused when the light transmitted through the center of the lens is more intense than the light transmitted near the edges of the lens. When the entire angle of view of the wide-angle lens must be used, more illumination to the edges of the original is needed to compensate for the falloff of light at the edges of the lens. This can be achieved by turning the lights slightly toward the edges or by moving the lights close to the edges. The amount of light increase necessary for the edges of the original is best determined by conducting exposure tests with the type of film being used. Lighting control is more critical when using an extremely high contrast film, compared to a high, moderate, normal, or low contrast film. Uneven lighting is more visible in a copy produced with an extremely high contrast film because of the limited exposure latitude of the emulsion. 8-14 contents Basic Photography Course <- previous page next page ->	As an Amazon Associate I earn from qualifying purchases.
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