PSAT Reading Practice Question 660

Question: 660

Color Photography
We tend to think of color photography as a
profoundly modern innovation, belonging to
an era no earlier than the 1950s. Although it
is true that it was not until the mid-twentieth
05century that compact devices like the Kodak
Kodachrome and Polaroid instant camera
made color photography widely available to
the American public, the first known color
photograph was developed about one hun-
10dred years prior, in the early 1840s.
Pioneers of color photography such as
American intellectual Levi Hill and renowned
French physicist A. E. Becquerel were
hampered in their efforts by a fidelity to the
15then-popular daguerreotype method, which
slowly imprints a direct-positive image onto
a metal plate treated with light-sensitive
iodine and bromine crystals. Colloquially,
these photographs were known as "tintypes."
20Color variants of this method—such as Hill's
toilsome "heliochromy"—often took several
days to develop and yielded only dim images
with colors that faded rapidly when exposed
to direct light.
25A new approach was required before color
photography could emerge as a truly viable
artistic and documentary medium. Such
an approach was theorized just ten years
later. While Hill's and Becquerel's labors had
30emphasized the search for a novel, chamele-
onic compound to assume any spectral
wavelength shown upon it, Scottish physicist
James Clerk Maxwell used as his model the
color sensitivity of the human eye.
35We are able to perceive colors because of
specialized photoreceptor cells lining our
retinas called "cones." Generally, humans
possess three types of cone cells, each of
which produces a distinct, transmembrane
40photopsin protein. Depending on the par-
ticular chromophore compound associated
with the cell's photopsins, the cone will have
a peak absorbance of electromagnetic radiation
at wavelengths of 420–440 nm, 534–545
45nm, or 564–580 nm. On the visible spectrum,
these peaks correspond to the colors red,
green, and blue, respectively. The brain's
integration of photons absorbed by these
three types of cones allows us to perceive col
50ored light with wavelengths between roughly
400 and 700 nanometers, which comprises
the entire visible spectrum. Because of this
mechanism, humans are said to possess
trichromatic vision.
55In light of this phenomenon, Maxwell
noted that any hue of visible light could be
reproduced by a specific combination of
three colors. Thus, three black-and-white
transparencies of a single scene taken
60through red, blue, and green filters will, when
projected as a composite image, reproduce
with impressive accuracy the original, full-color
subject. Problems remained, however,
when it came time to develop these nega-
65tives onto paper in that the dyes used by
photographers were ineffective in expressing
certain colors, particularly those comprised
of lower wavelengths. By trial and error, it
was discovered by Becquerel and German
70chemist Hermann Vogel that the addition of
dyes made of aniline—an aromatic amine—
and chlorophyll to photographic emulsions
helped to reflect the reds and yellows that
previous dyes had simply absorbed.
75Into the early 20th century, color cameras
themselves remained somewhat unwieldy;
this owed largely to the logistical complexi-
ties of exposing three separate, individually
filtered plates on the same subject. One
80design used a system of prisms and mir-
rors to split the lens image through three
internal filters, which in turn exposed three
plates simultaneously. A more compact and
less delicate device designed by German
85photographer Adolf Miethe simply included
a rotating filter disk, which allowed three
photographs to be taken in rapid succession.
From 1909 to 1915, Miethe's design was used
by his Russian protégé, Sergei Prokudin-
90Gorsky, in a project appointed to him by Czar
Nicholas II to document visually the history,
culture, and modernization of the Russian
Empire. His extensive and compelling work
in the Russian provinces constitutes the
95first major series of color photojournalism.
However, whenever a moving object was
included in the frame—particularly water—
the shortcomings of Miethe's design became
obvious. The consecutive exposure of plates,
100however swift, would always leave some
room for visual conflict between the three
images.
The issues of both convenience and syn
chronous exposure were eventually solved
105by two professional, classical musicians—
Leopold Mannes and Leopold Godowsky,
Jr.—working recreationally for the Eastman
Kodak Company. Together they designed a
film that consisted of three separate emul-
110sion layers mounted on a single flexible
base, each of which captured and individu-
ally filtered the lens image. Their design
was marketed by Kodak under the name
Kodachrome and was the first system to
115make the use of color film widely available
to lay photographers.
Electromagnetic Waves and Their Wavelengths
Wave Type
Wavelength in Meters
Gamma
1 × 10–11
X-ray
1 × 10–9
Ultraviolet
2 × 10–8
Infrared
1 × 10–6
Radio
1.0

Based on the information in the passage and in the table, light visible to humans would have wavelengths between which two types of waves?

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