color

The Illusion of Color in Astrophysics

Gianni Sarcone

Study on Colors in Astrophysics – Ongoing Research

Under specific atmospheric conditions and with the technological tools employed, stars or planets may appear to emit green or blue light to some observers. However, as illustrated in the accompanying diagram, this is often nothing more than an optical illusion. The blue region seen in the diagram is actually a medium gray, entirely desaturated. You can verify this by using Photoshop’s color picker tool (or an analogous method) to check the true color values.

This phenomenon raises interesting questions about how color perception in astrophysics can be influenced by both atmospheric effects and the limitations of observational tools. How much of what we “see” in the cosmos is truly the color of the objects themselves, and how much is a product of the interaction between light, our atmosphere, and the instruments we use to detect it?

The Enigmatic Color of the Sun

Gianni Sarcone

Is yellow the true color of the sun? Our sun emits a broad spectrum of radiation, including visible light, which is crucial for life on Earth. In the vacuum of space, the sun appears white because it emits light across all wavelengths fairly evenly. However, when this light enters our atmosphere, it encounters air molecules and particles that scatter shorter wavelengths—primarily blue light—more effectively than longer wavelengths like red and yellow.

color of the sun

Simultaneous Color Contrast Explained…

Consider a small, clear disc placed against a blue background. The disc may appear slightly yellow due to the influence of the blue light surrounding it. This visual effect is similar to how we perceive the sun against the blue sky.In essence, while the sun itself emits white light, our atmosphere alters its appearance, leading us to see it as yellowish or orangish at times.

Additionally, not all species perceive colors in the same way. Different animals have varying sensitivities to wavelengths of light. This means their experience of color and light can be quite different from ours.

For more fun facts about color perception and optical illusions, visit Archimedes Lab.

Amazing Brightness Constancy Effect

Gianni Sarcone

Look carefully at the saw-tooth wave patterns on this picture. Is the background of the picture uniformly gray or are there different shades of gray?

Kolozanges (2013-2021), © Gianni A. Sarcone

Brightness constancy makes some vertical strips look darker, when in fact the gray background is all the same shade of gray.

This op art work is available as prints and canvases from my official online Gallery.

Is Magenta a Real Color?

Gianni Sarcone

Most of us are familiar with magenta — it’s a kind of purplish-red that exists between blue and red on color wheels (color wheels don’t accurately represent the physics of photons, but they represent the philosophical reality: color is a human construct that helps us interpret wavelengths to better understand our world).

The odd thing about color vision is that magenta (or pink) color is not in the spectrum of colors, meaning it cannot be generated by a single wavelength of light. Our brains interpret the color sensation of magenta/pink as ‘absence’ of green.

Source: https://www.archimedes-lab.org/Gallery/new_optical_illusions/pages/10n-Pink_rose.html

magenta

You Can’t Possibly Color This!

Gianni Sarcone
You_cant_possibly_color

An Impossible Optical Illusion Activity Book

No mere coloring book, You Can’t Possibly Color This! is an eye-spinning experience that will inspire and astound. That’s because you’ll be coloring in optical illusions — things that can only exist on the page. With a just a few tips, you’ll be coloring in things that will bulge, expand, and even rotate. Other objects will leave you confused as you try to figure out the “trick,” while mandalas, complex patterns, and labyrinths will mesmerize you. Also included are fun activities for drawing and creating your own optical illusions.

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Illusive Op Art Skulls

Gianni Sarcone

I am currently working on new “neon color spreading” effects. Have a look at the pictures below… Though you perceive fluorescent grinning skulls, the vertical white stripes don’t contain any color at all, they are uniformly white! The trick lies on the fact that some black lines have very thin color edges. This illusory shading effect is also known as “subjective transparency” or “Tron effect”.

The neon color effect was first observed by D. Varin in 1971. The human ability to perceive a neon effect may be a remnant of the development of our power of sight under water at extreme depths, where light is very poor.

My Op Art Skulls are available as prints and t-shirts from my online store.

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Different but Equal

Gianni Sarcone

It happens sometimes to read on a snack the following notice: “with chocolate taste”, written in uppercase. This statement tricks our mind! In fact, the vast majority of us think that such a snack MUST contain chocolate, no one thought however that a flavor is not a substance and most probably the snack we bit into contains only an ‘illusion’ of chocolate.

The same occurs with colors, our brain is easily tricked by them. Colors are just like ‘flavors’, they may smell, pardon… look like a specific color, but they are just an illusory subjective sensation, not an ‘external’ reality. Colors undoubtedly change depending on their surrounding or the context in which they are viewed. More mind-blowing still is the fact that colors that are identical may appear to be different under certain conditions, and colors that are different may look the same. Such a curious effect is called “color induction”. Continue Reading →