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What is the material that opaques the light?

Transparent or translucent materials.

Not all materials are opaque to sunlight. Transparent glass, plastic, and water, for instance, are transparent and transmit light directly, while tracking paper, clouds, and ground glass diffuse the light they convey and are referred to as translucent.


In either case, if the material is colored, it will allow lighter of those wavelengths to pass through it than other types. Deep red windows transmit red wavelengths but can be almost opaque to blue light.

As the translucent materials diffuse the lighting, they feel milky when they are kept in light and have more uniformly lit air than brighter materials, even when the light source is not aligned directly behind them.


Slide previews and light boxes work according to this principle. The quality of the light is like that reflected by a white diffuse area.


Refraction


Interesting things happen when direct light travels obliquely from the air to another transparent material. As mentioned above, light moves a little slower as it passes through a thicker medium. When the light passes under the angle of the air into the glass, for example, its wavefront.


This is because a portion reaches the denser material first and shifts the direction of light, such as driving a car to an angle in the sand. A new straight route is formed, slightly steeper in the glass. The shift of light trajectory when light passes obliquely from one transparent medium to another is known as refraction.


You can see the refraction at work when you push a stick straight into the clear water; it looks folded to the water's surface. A thick window may produce similar distortions. This is important because by using refraction, the lenses fold the light and thus form pictures, as we will see.

Remember that the refractive only bends the oblique light. The light which hits the border of two transparent materials at right angles slows down meticulously without changing direction. And much of the light reaching the limit at a very small angle is reflected from the surface.

The entire story.


Everything we see in the world that surrounds us seems to be what it is because of the mixture of effects it has on the light - diffuse and specular reflection, absorption, often transmitting and refracting.


An apple lit laterally by direct sunlight for example reflects the highly colored wavelengths of its illuminated half.


Most of these elements are reflected diffusely, but part of her smooth skin reflects a bright specular glow, exactly where the angle of the sun at the surface corresponds with the angle of that point at your eye.


The shape and relative obscurity of the shade on one side of the apple gives you further hints about its shape. From experience, your eyes and brain recognize all these "signals" of subtle light to mean strength and roundness, without you having to touch the apple to discover it. That's the definition of "see". Photography enables us to make the image permanent and portable so that others can experiment with it. The film cannot translate exactly how we view light with our eyes and different kinds of film record light and color in different ways. As you familiarize yourself with the type of film you use, you will begin to understand how it reacts to light and shade. With a high-specification digital camera, you can change color intensity and type in commands; however, the camera still can't record exactly as you see and that's part of the magic of photography: that it turns the world we see into a picture.

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