How Fluorescent Colors Work

Conventional color pigments absorb visible light energy and convert it into visible wavelengths of light. So a white light can bounce back to you after interacting with a red sweater, and you'll see the light coming into your eye as red. 

Neon or fluorescent acrylic paint

Fluorescent—or "neon"—colors do that, too, but they have an additional trick. Fluorescent colors also absorb and convert ultraviolet rays, which are invisible, and convert them into visible light. Fluorescence shifts energy in the incident illumination from shorter wavelengths to longer (such as blue to yellow) and thus can make the fluorescent color appear brighter (more saturated or lighter in luminance) than it could possibly be by reflection alone. The absorbed energy excites electrons in the pigment molecules to a higher energy level, which then relax back to their ground state by emitting light at a longer wavelength than that absorbed, resulting in a visible glow

As a result, your eye perceives a far more saturated color or a tone that's higher in tone relative to the white paper they're drawn or painted on.

Ultraviolet light is usually present in outdoor light, whether direct sunlight or overcast. Without a source of short-wavelength light (like a black light), the fluorescent pigments won't stand out. As soon as you add an ultraviolet light source, the fluorescent pigments will appear to glow, while conventional colors remain dull and hardly visible. If a subject is lit only by ultraviolet light and no visible wavelengths, fluorescent colors will appear to glow magically in the dark. 

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Neon or fluorescent acrylic paint 

Fan Ho's Bounded Light

One way to capture light is to surround it with darkness. 

The photographs of Fan Ho, who explored Hong Kong in the 1950s, often use this principle.

Within the area of light, the dark elements are lightened by backlit atmosphere. 

The light patch coheres as a single shape, with dark elements jutting into it.

The light enters the dark space and casts shadows from each of the forms.

The key figure appears backlit in the central region of light.  

If you follow around the outside border, it's almost all in deep shadow.

The charcoal fires and cigarette smoke made for bad air quality, but it was a gift to photographers.

When he introduces color into this scheme, it's a revelation.

Books: 

Portrait of Hong Kong 念香港人的舊 

Magnum Contact Sheets  

Light on the Landscape: Photographs and Lessons from a Life in Photography

Komorebi

The Japanese language has a word for light streaming through a forest: komorebi. 

Photo of komorebi by James Gurney

The word refers to sunbeams interacting with leaves and atmosphere as the rays pass through the trees and fall in dappled patches on trees, the forest floor, or curtains in a cabin.

It also conveys a sense of nostalgic longing for something or someone far away.

Painting a Sunset Glow Effect

Arthur Parton, Lake Scene, 1876

Several artists have accomplished this effect of a big gradation around the sun, which influences everything around the source. 

Frederic Church

It's kind of difficult to paint this situation from real life because you can hurt your eyes looking straight into the sun. If it's veiled behind enough clouds, you can do it. Scenes like this are composed from memory and imagination. 

Russian seascape painter Aivazovsky often applied the effect to seascapes. He suppresses contrasts in the far waves, allowing the big gradation to envelop them. 

Franz Richard Unterberger, Venice Under Sunset

Unterberger captures an effect that is more of a perceptual impression than a photographic transcription.

Hopper's Light: Evocative or Illogical?

Did you notice that something is missing in this picture? It's the cast shadow from the horizontal sash of the window. Also, the shaft of light is far wider than the window, and the rays of light aren't parallel.

Sun in an Empty Room, by Edward Hopper

Hopper also ignores the effect of the secondary source of soft blue skylight that would influence the base of the wall adjacent to the shadow, and he leaves off the baseboard moulding at the edge of the shadow.

John Walsh of Yale University gave a lecture on YouTube, which discusses Hopper's manipulations of light and geometry. The bottom image shows a digital reconstruction Wash commissioned to show the window shape necessary to achieve the light patch. To skip ahead, visit the video at about 12:00 and 47 minutes.

Are these faults or are they fair choices to make a more striking picture? I can see why Hopper didn't want to make the sun patch smaller or to cut it up with cast shadows. The painting is about emptiness and it's a big statement of light and shadow. There's not much else to look at here. 

Rooms by the Sea by Edward Hopper, collection Yale Art Gallery

There are a lot of things wrong here, too. He shows a slanting shape of light cut off on the left, as if it's limited by the top of the doorway. That's OK. But the bar of light across the floor has a similar angle. Something feels wrong about that.

Perhaps he remembered seeing the light effect and constructed it in a way that felt right to him geometrically. But it's completely impossible.

I set up a quick cardboard maquette to show the problem. That shadow across the floor shouldn't have an angle to it. It must be a straight line from the edge of the door to the base of the wall.

Do these criticisms seem trivial or pedantic? I hesitate to share them because I like Hopper's work.

But art should stand up to hard looking. Once I start noticing how illogical the light is (not to mention the perspective and the carpentry details), it's harder to appreciate the sentiment of the picture. It's like trying to walk with a pebble in your shoe. 

An artist has freedom to do anything he or she can get away with if the resulting painting communicates more effectively. But its probably best to make a statement that's consistent with truth.

Painting a Spotlight Effect

New YouTube video (Link to YouTube) explains how to focus sunlight on one part of a plein-air painting using a spotlight underpainting. The car is a 1962 Chevy Impala.

Fishermen

The guy holding the pole caught a fish. He says he doesn’t eat fish and gives them all away.

Fishermen on Santa Monica pier, 1981

I made this sketch on location at the Santa Monica pier using a brush and ink to capture the late-afternoon edge lighting. Regardless of the local color of each form, I rendered anything in shadow as black and left anything illuminated by the sun as the white of the paper.

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From "The Artist's Guide to Sketching, 1982

Light Temperature

Artificial light is rated according to its color temperature, listed as a Kelvin number (Celsius degrees). 

When you heat up an incandescent filament, it radiates light. At lower temperatures, the filament gives off a more orange or yellow light. As it gets hotter, the color it radiates becomes bluer. 

Comparison of light temperatures via Reddit

When you buy a bulb, it is rated on this scale. In this photograph, a series of bulbs are lined up in a gradation from 1000 K to 10,000 K. Although the scale was created based on incandescent light, it is used for LED and fluorescent light as well.

A candle flame is about 1900 K. Bulbs that produce light at 2-3,000 K are often called "warm white" in the industry. White, neutral sunlight is rated at 5,000 or 5,600 K. Studio north light is closer to 6500 K and above that, the pure blue sky can go all the way up to 10,000 K.

This scale can be confusing or counterintuitive for artists, because the bluish paint colors that we call "cool" are associated with the light that is emitted at higher temperatures, while "warm" colored light comes from cooler sources.

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Reddit: Comparison of light temperatures

Wikipedia: Color Temperature

Painting While Facing the Light

How can you capture light in a painting while facing toward the light? I've got a new video that you can watch here or on YouTube.

››

The technique uses watercolor, gouache, and pastel over a casein priming to capture the feeling of objects against a bright sky. I also discuss whether it ‘breaks the rules’ to combine gouache, watercolor and other mixed media.
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RELATED BLOG POSTS
Should Watercolors Be Purely Transparent?
Contre Jour Lighting
Light Spill

Volumetric Lighting

Volumetric lighting is a concept from 3D digital graphics that can be helpful for painters to consider.

Screenshot from the game Fallout 4

When smoky or dusty atmosphere is illuminated from behind, sunbeams appear.

We painters tend to think of these beams in two-dimensional terms, but it's good to remember that they occupy a specific volume of 3D space between the source and the subject.

Still from "The Man Who Wasn't There" directed by
the Coen Brothers, cinematography by Roger Deakins

If the light comes from a sharp, hard source (as opposed to a soft, diffuse one), it can take on a particular shape with fairly sharp edges. The slices of light are most visible against dark background areas.

Albert Bierstadt, Lander's Peak

The light takes on its form as it passes through the opening in the clouds, and you can see its effect as it travels to the selective areas it illuminates.
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Previously:
Sunbeams
Light and Form, Part 1
Book:
Color and Light: A Guide for the Realist Painter

Van Schendel's Moonlight Markets

Petrus Van Schendel was born today, April 21, in 1806. 

To paint his famous candlelit scenes, he divided his Brussels studio into two spaces: an illuminated part where he did his painting and a darker section where he posed his models. 

His outdoor market scenes often set up a contrast between lantern light and moonlight. The candles and lanterns illuminate the fronts of the figures, and each flame is surrounded by a glowing halo of light. The moonlight is relatively cool and the buildings only dimly seen in the shadows.

The challenge with painting the effect of dim light is to suppress detail in the shadows and to make the transitions gradual. We're accustomed to seeing photographic interpretations of night scenes, which typically include far more detail than the human eye can see.

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Wikipedia: Petrus Van Schendel

Controlling Light and Depth in Landscape

What makes me want to paint this scene is the way the light and atmosphere work together to create depth. Here's what I'm thinking as I paint it.

Farm in Harlem Valley, oil, 12 x 16

The cloudy sky has a low ceiling. The tops of some of the hills are lost in fog. Also the far horizon is enveloped by the low clouds, so the warm colors in the farthest fields are greyed down before they disappear.

The fields are illuminated in the lower left foreground. Then as you go back across the perspective of the plowed field, you travel through the shadow area and back into the light again.

 

The principal area of illumination is not on the farm buildings, but a little beyond them. The light is coming through a breach in the clouds with very subtle rays. 

Concealing both the source of light and the effect area adds to a sense of mystery. One way to make a striking light effect is to downplay and conceal most of the scene to set up for the accent area.  

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For more on light and atmosphere in painting, check out my book Color and Light can be found on Amazon or signed at my website.

Eight Portrait-Lighting Setups

Here are the eight most common setups for portrait lighting:

1. Three-Quarter Broad
Most portraits have light coming from in front of the model, and a little off to the side. The main or “key” light strikes three-quarters of the visible form, leaving one-fourth of the form on the far side of the face in shadow. Typically, the key light is elevated from the subject’s line of sight. It’s high enough to leave a shadow under the nose and chin, but low enough to get some light into both eyes. The light casts a shadow from the nose onto the far cheek, leaving a lighted triangle on that shaded cheek. If the face is turned slightly to one side, the near or “broad” side of the face is the one receiving the major illumination, which is why it’s called broad lighting.

2. Three-Quarter Short

Alternately, light can come from the farther, foreshortened, or “short” side of the face. It’s still three-quarter lighting if the tell-tale lighted triangle appears on the shaded side of the face. This time the lighted triangle is on the cheek closest to the viewer. Short lighting can help make a face look thinner. Some photographers use the term “Rembrandt lighting” more generally for any three-quarter lighting, either broad or short. Rembrandt himself used both broad and short lighting. Both of these lighting arrangements are flattering and unobtrusive, good reasons why portrait painters and photographers have used them almost universally.



3. Side or Split Lighting

Light that comes straight from the side is called side or split lighting. The dividing line or terminator between light and shadow runs along the centerline of the face. It’s not a light arrangement that you see too often, but it has its purpose, especially
in film, comics and illustration. It places equal importance on the light side and the shadow side, so it can convey the sense that the subject is a doppelganger, a person whose soul is a battleground of equal and opposing forces. Sometimes two equal light sources shine onto each side of the face without quite overlapping, leaving a dark core shadow running down the forward-facing planes in the center of the face.

4. Top Lighting
In top lighting, the light comes straight down onto the head from above. It occurs often under a streetlight, a ceiling light or a noonday sun. The forehead and the nose intercept most of the light. These parts of the face carry relatively little expression. The mouth and eyes, the chief agents of sympathy, are lost in shadow. As a result, the subject’s emotion is masked. The effect can be threatening, mysterious or inscrutable. This lighting arrangement is ideal for a dramatic entrance of a dangerous character or for conveying a feeling of cool detachment.

5. Light from Below
Strong light usually doesn’t come from below, so when you see it, it grabs your attention. We tend to associate warm-colored under-lighting with firelight or theatrical footlights, which can suggest a magical, sinister or dramatic feeling. In modern times a cool light from below suggests a cellphone or a computer. Faces that are familiar to us (family, friends and celebrities) nearly always appear lit from above. We hardly even recognize them when we see them with the light shining upward on their features.

6. Frontal Lighting
In frontal lighting, the light travels straight toward the form from an angle close to the viewer’s line of sight. The planes get darker as they turn away, and the planes facing us are lightest. Frontal lighting tends to flatten the form, and it emphasizes the two-dimensional design instead of the volume. It can give the picture a striking poster-like impact. It’s a good lighting to choose if you want to emphasize color or pattern. Frontal lighting is one of the few times when outlines actually appear in real life. The outline is really the thin fringe of shadow that appears at the very edge of the form.

7. Edge or Rim Lighting
Edge lighting comes from behind to touch the sides of the form, separating it from the background. It’s also called a rim light or kicker in the film industry, and it usually requires a relatively strong source of light. The width of the rim light varies according to the size of the planes that face backward to the light. Edge light is not just a thin white line around the form. If you want to introduce an edge light source, it should be a different color from the ambient light on the front planes.

8. Contre-Jour Lighting
Contre-jour lighting is the opposite of frontal lighting. The planes that are darker in one system are lighter in the other. The head appears against a field of light, which might be a bright sky or an illuminated doorway. The field of light takes on an active presence, surrounding and burning out the edges of the silhouette. The darkest tones are on the front-facing planes and the hollows of the form.
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These eight portrait lighting setups are featured in the current issue of International Artist Magazine.

The information also appears in my book Color and Light: A Guide for the Realist Painter (James Gurney Art)

Tips for Painting Lamplight

Jeff asks: "Any tips for conveying the effects of candlelight or lantern light in a painting?"

Jeff, yes, let's take a look at Viggo Johansen (1851-1935). He was a Danish painter in the Skagen group, and like his colleague Krøyer he loved to paint gatherings of friends around the dinner table. His painting Evening Talk includes a lantern on the table and two candles on the piano.

Viggo Johansen, Evening Talk, 1886

Johansen does a few things to make the effect of light convincing. 
1. The areas of dark are large and simple. Note how in the lower part of the picture, it's very hard to make out the details of the chairs and table legs.
2. The edges between forms in the outer areas are kept soft. Note the way he paints the framed canvases on the wall. They're quite blurry and out-of-focus.
3. The fall-off rate of the light roughly follows the inverse square law.
4. The effect area under the lantern is small, crisp, and detailed: lots of dots and sparkles.
5. The area of the lantern itself is a flat, warm white, with more or less glow or halation around it depending on the amount of smoke in the air.

Viggo Johansen, An Artist's Gathering, 1903

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Wikipedia Viggo Johansen (1851-1935)
More in my book: Color and Light: A Guide for the Realist Painter (James Gurney Art)(Amazon), or Color and Light (Signed on my website)
Previously on the blog:
Fall-Off
Candlelight

Red Shadowline

14 hours ago

A Twitter user asks: "Hey James. Can't find the answer to this anywhere else, but do you know what you would call this red line on the skin?"

Answer: That looks like subsurface scattering. The sunlight penetrates the skin and scatters a short distance beneath the surface.


It comes up to the surface across the shadow line with the same reddish color you see when you hold your fingers.

The warm color in the nasolabial fold is a combination of subsurface scattering and reflected light from the illuminated alar planes of the nose.
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Previously on GurneyJourney
Subsurface Scattering I
Subsurface Scattering II