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Bài đọc tiếng Anh, English, Kỹ Thuật, Photography, Tìm Hiểu

Everything You Wanted To Know About Contrast

by Ivor Rackham

Contrast means so much more than the separation of light and dark. Understanding the different types of contrast can train our photographic eyes and improve our Images.

We usually think of contrast as the difference between the darkest and brightest parts of the photo, in other words, the separation of tones. The more pixels there are pushed away from one another and towards the extremes of white and black, the more contrast the image has.

Open an image in your favorite processing software and push the contrast slider to both extremes and observe the histogram. Watch as the pixels represented in the graph move further apart as contrast increases, and then move closer together as it is reduced.

On a practical level, knowing about tonal contrast is useful in photography. In black and white photography, for example, we can only distinguish between subjects if there is tonal contrast. A lot of successful monochrome images have strong shadows and highlights, although this is not always the case. Low contrast black and white photography can sometimes work too.

Low contrast black and white image

However, difference in tonal values is just one aspect of contrast that we should consider in our photography. Although important, contrast can mean much more than just that. Johannes Itten (1888-1967) promoted a broader definition. He was a Swiss expressionist artist and teacher of the preliminary course at the Bauhaus School. He proposed seven basic color contrasts, and awareness of these in photography can also help us improve our work.

Itten’s Seven Color Contrasts

1. Light and Dark

This is the tonal contrast described above, and the first of Itten’s seven contrasts. A low contrast image may have no blacks and/or whites and all the tones are bunched together, such as the image shot in the fog above.

Meanwhile, a low-key, chiaroscuro image will have strong contrast with heavy blacks and shadows and areas of, bright light. In painting, the artist Caravaggio created high contrast chiaroscuro work in an extreme style known as Tenebrism, where dark dominates, there are few mid-tones, and the smaller areas of highlights draw one’s eye. This approach can be employed in photography.

Low-key, Chiaroscuro image of a gray heron

Similarly, high-key images also show light and dark contrasts, but with the highlights dominating the frame.

Arctic Tern. High-Key image where the whites and highlights dominate the frame.

2. Cold and Warm

This is the contrast between warm oranges, reds, and yellows, and cooler blues. It should be noted that warm and cool here refer to the psychological meanings of the colors. In physics, blue light has far more energy and is thus hotter than the red end of the electromagnetic spectrum. The most common cold and warm contrast we see in photography is orange against blue: the sunset against the sea, autumn leaves against the sky.

Warm foregrounds and cooler backgrounds increase perspective in an image, while the reverse reduces perspective. You may see in the following image that the orange of the sunset seems closer than the blue horizons to either side.

The warm orange tones of the sunset are complementary colors to the cool blues of the sky.

3. Hue

This contrast is formed by the juxtaposing of different hues. A greater distance between hues on a color wheel produces a greater contrast. So, red and orange have low contrast, whereas red and green have the highest color contrast.

4. Complementary

Related to the contrast by hue, and sometimes grouped together with it in Itten’s color contrast, complementary colors are those on the opposite sides of the color wheel.

In very simple terms, if we take the two primary colors and mix them together, we get a secondary color: red and blue make purple, blue and yellow make green, and yellow and red make orange. The complementary color of the secondary color is the primary not included in its composition. So, green does not include red in its composition, so red and green are complementary colors. Orange does not include blue, so they are complementary to each other, and likewise purple is complementary to yellow. True complementary colors are opposite each other on a color wheel.  

Color wheels are readily available as apps, or on websites such as Adobe Color

5. Simultaneous Contrast

Have you ever looked at a strong red against a strong green and the colors seem to vibrate against each other? This is simultaneous contrast. It’s the way in which one color can affect the way we perceive another.

As you scroll the page or move your eyes over this image, the green spots may seem to jump and vibrate against the red. This is an example of simultaneous contrast.

Additionally, simultaneous contrast also refers to the effect a color has on its surroundings. For example, if you place yellow objects on a gray background, the background seems to take on a purple hue. If we do the same with red on a gray background, the background appears slightly greenish. In the following diagram, all the small gray boxes are the same gray tone, yet they can appear to take on the complementary color of their surroundings.

The gray internal squares are identical in tone, yet they may appear to be different shades and your mind may even make them appear tinted with the complementary color of the outer colored box.

6. Quality (Saturation)

These are contrasts in saturation, pale muted colors against strong, saturated ones.

7. Quantity

A typical example of contrast by quantity would be a little splash of color against a backdrop of another hue.

A tiny splash of red from the lighthouse in the predominant blue after-dusk light draws one’s eye to it.

Physical Contrasts

Itten set his students tasks to explore other possibilities of contrasts. Although he was concentrating on art and design, applying the same principles in photography make our images more compelling. These contrasts were physical opposites, such as points and lines, horizontal and vertical, thick and thin, small and large, tall and short, many and one, etc.

Being aware of contrasts can improve our photography. Instead of just lifting the camera to our eye and shooting, we can use them to help tell the story to the viewer about what it is we were trying to portray. In other words, it shows the intelligence behind the photograph.

Of course, not all photographs have to contain such contrasts. A soft, repeating pattern of ripples on the water, or a field of golden wheat which is similar textures, shapes, colors, and tones can still make compelling shots.

The contrasts here are the tiny figures against the enormous sky and sea, plus their hard, dark forms against the soft and fluid mid-tones of the environment.

What is Micro-Contrast?

There is a lot of hogwash written about micro-contrast at the moment. It’s a trendy topic in internet forums.

Look through a cheap piece of greenhouse glass and, although you can discern what you are looking at, the edges of fine lines will blur into one another. In comparison, good quality window glass can appear almost invisible; you can see the fine edges. The same applies to lenses. High-quality lenses produce much sharper images because they can show tiny differences in tone much more effectively than most consumer-end lenses. Micro contrast is the ability of a lens to transmit those small differences between tones. In other words, a lens with high micro-contrast is sharper.

Modern technology allows most consumer-end lenses to have excellent micro-contrast, far better than many pro-lenses produced thirty years ago. However, “better” in this case is subjective. There are plenty of people who enjoy photography using old film lenses.

Personal Challenge

If you want to explore contrast, make a list of opposites. Then, using the genre of photography that appeals to you, take a series of images that demonstrate those opposites. You can either shoot single photos that contain the two extremes, or alternatively pairs of photos that depict opposites of each other. Do upload them to your online gallery and please post a link in the comments, as it would be great to see them.

All images © Ivor Rackham 2005-2021

(Sources : fstoppers.com)

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