The Minnaert Project
A Visual Approach
By: Xijia Chen
7/23/2016
1
The Book and The Project
• The Book
– M.G.J. Minnaert’s: Light and Color in the Outdoors
– Scientific explanations for multiple lighting
phenomenon
• The Project
– Purpose: To capture examples of the abovementioned effects in order to demonstrate and
compliment his descriptions
– Reason: A picture is worth a thousand words
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2
Equipment Used & Places Traveled
• Digital Camera:
– Kodak DC280
• Places Traveled
– Stanford University, Stanford, CA
– Shoreline Park, Mountain View, CA
– Foster City, CA
– Fisherman’s Wharf, San Francisco, CA
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3
Reflection by the Clouds
• Characteristics of Clouds – p.324, Section 235
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Dazzling white where sun illuminates them
Gray underneath as they pass overhead
Opaque white body -- light reflected by numerous droplets of water
“Silver lining” if sun is covered by cumulus cloud
Often vivid colors during sunrise/sunset
Shoreline Park, CA
Shoreline Park, CA
4
Shadows
•
“When you look at your shadow on the ground, you will notice that the
shadow of your feet is clearly defined, whereas that of your head is
not. The shadow of the bottom part of a tree or post is sharp, while
that of the higher part part becomes increasingly unclear toward the
top.” – p. 4
Stanford University, CA
•
Notice near the base of the lamppost, the shadow is distinct and mostly
consists of the umbra, whereas at the bulb, the penumbra is more
visible and the shadow is much less crisp.
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5
Shadows (continued…)
Stanford University, CA
•
Notice that the spokes at the bottom of the tire are slightly visible whereas
those at the top are not due to the merging of the penumbra and umbra. This
is another example of the gradation from clear to blurry shadows.
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6
Differences Between an Object and It’s
Reflection (Part 1)
•
“…the reflection of a scene in calm water resembles the scene itself upside down.
Nothing could be further from the truth…The reflection of a bank sloping towards
a river appears shortened…” – p. 11
El Camino Reale, Stanford, CA
•
Notice that the distance from the real car and brown hill to the curb (marking the
horizon) seems larger than the distance from those objects to the curb in the
reflection
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Differences Between an Object and It’s
Reflection (Part 1 …continued)
•
Explanation – Although the object and it’s reflection are identical, their
positions are different, therefore the perspective of the viewer w/
respect to each is shifted differently:
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8
Differences Between an Object and It’s
Reflection (Part 2)
•
“Clouds are never as beautiful as when they are reflected in a mirror”
– P. 13
•
The reflection of clouds in the water is clearer than the clouds in the
sky.”
– P. 20
Shoreline Park, Sunnyvale, CA
•
Notice whereas the sky is almost white, the clouds in the canal are
fairly distinct
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Differences Between an Object and It’s
Reflection (Part 2…continued)
• Explanation: Mostly psychological
– The reflected view always associated as being in a
plane
– ‘framing’ of the picture results in uncertainty about
the position, giving an impression of relief
– Protects our eyes from brightness of directly
looking at the sun
– Polarization of reflection = luster attenuated and
colors saturated
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10
Freak Reflections
•
“A row of houses throws a dark shadow on to the road, but in the
middle of this you often see spots of light…it is reflected by the
windows of the houses on the other side of the road.” – p. 15
Stanford University, CA
•
Although all of these surfaces were in shadow, they each exhibit one or
more bright spots due to reflections from opposing windows.
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11
Reflections in Soap Bubbles
•
•
“Try blowing soap bubbles…The side turned toward us…shows the same upright
images as the spherical mirror,…the inside back…inverts the images.” – p. 21
“The magnificent shades of color, the changing tints…” – p. 21
Stanford University, CA
•
In the left bubble, both the ceiling light, bubble wand and their respective
inverses can be seen. Although the right bubble only shows the ceiling light, the
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striations of the rainbow colors can be faintly seen.
12
Window Glass vs. Plate Glass
•
“The reflections from windows indicate whether they are of normal
window glass or plate glass: if the latter, the images are fairly clear, if
the former, they are so irregular that the uneveness of the glass can be
seen clearly” – p.22
Rengstroff House,
Shoreline Park
•
Foster City, CA
Notice how the image in the left window is almost a mirror reflection,
whereas the cars in window on the right curve upward and then back
down
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13
Irregular Reflections by a Slightly Rippled
Surface (Part 1 – Houses)
• Dominance of Vertical Lines in Reflections
– “…A chimney or a thin mast is reflected clearly, but the strong lines
of the roofs have disappeared: only the vertical lines are found
back in the reflections.” – p. 24
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Foster City, CA
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Irregular Reflections by a Slightly Rippled
Surface (Part 1…continued)
Foster City, CA
•
Notice that in both pictures, the vertical lines of the chimney are strongly
apparent whereas the horizontal lines are blurry and indistinct
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15
Irregular Reflections by a Slightly Rippled
Surface (Part 2 -- Streetlights)
• Vertical Columns of Light (Streetlights)
– “Observing a streetlight at night gives us the ‘elementary phenomenon’…an upright
line, the columns are neatly stacked together and magnify each other; … a
horizontal line, they lie side by side and broaden the line to a hazy surface.” – p. 24
Fisherman’s Wharf, San Francisco
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Irregular Reflections by a Slightly Rippled
Surface (Part 2…continued)
Fisherman’s Wharf, San Francisco
–
In both pictures, the reflection of the streetlamps are stretched in the vertical direction. Since
the water is slightly rippled, each wave reflects a separate image, gently adding up to an
elongated column that remains vertical in the plane of our eyes regardless of whether the
lamps are actually in the plane of the page (previous page -- the lamp on the left) or tilted out
of the plane of the page (previous page -- the row of lamps on the right). This verticality is
sometimes affected by factors such as wind, etc.
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17
Closed Light Coils
•
“Remarkable is the appearance of closed coils of light seen when the
water surges gently, the waves have short crests, and the light source
is high.” – p. 31
Shoreline Park, CA
•
Explanation: If you look at the water at a large angle, the light is
reflected by two separate spots of light on each wavelet. By looking
left or right, the reflections will appear to get closer together until they
fuse into the closed irregular annulus that you see.
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18
The Shifting of Reflected Images Toward the
Horizon
•
“The reflection of the sun in the waves is a dazzlingly bright patch, which, as the
sun sets, is more or less triangular in shape, showing a shift towards the
horizon.” – p. 35
Foster City, CA
•
Shoreline Park, Sunnyvale, CA
Notice that the photo on the left (taken towards sunset at high wind) has a
triangular reflection whereas the reflection in the photo on the right is very
obviously a vertical column
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19
Stained-Glass Windows
•
“Even the most brightly colored stained-glass windows look dull when seen from
the outside.” – p. 124
Stanford University, CA
•
Whereas from the outside, the stained-glass looks somewhat dull and
dark because the light is reflected and the light coming from inside is
faint, from the inside, the colors burst to life due.
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20
Scattering of Light By Clouds
•
“Certain kinds of cloud obscure the sharp outline of the sun until only a round
mass of light remains that grows fainter towards its periphery.” – p. 283
San Francisco, CA
•
By blocking the sun’s disk, the cloud has obscured the sun’s light exactly as
Minnaert’s book describes. Even more intriguing are the distinct “rays” or
“bands” of sunlight that emerge from the clouds, tracing a clear path across the
sky.
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21
Refraction by an Undulating Water Surface
•
“When a water surface is not perfectly smooth, this is revealed by a change in
direction of broken rays of light and an uneven brightness at the bottom.” – p.
46
Stanford University, CA
•
The brightness of the water is obviously uneven in this fountain behind The
Memorial Church. Clear patches of bright white interspersed with darker colors
illustrate the “broken rays of light” effect.
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22
The Colors of Sunset
•
“The light that we see at sunset in the direction of the sun has the blue
component removed, so that we see a red sun.” – Plate 35
San Francisco, CA
•
The scene around Alcatraz at sunset is tinted pink because of the
scattering of blue light due to the longer distance light has to travel
through the atmosphere in order to reach our eyes.
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23
Miscellaneous:
•
Distant houses only reflect the light of the rising or setting sun – p. 10
San Francisco, CA
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Fin
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