The orange cube exercise
Summary
TLDRThis video script introduces an exercise using an orange-painted cardboard cube to explore three types of color perception: object colors, illumination colors, and colors reaching our eyes. It challenges viewers to consider whether they perceive the cube's faces as differently colored due to light or as uniformly colored under varying illumination. The script delves into how our visual system interprets these colors, the concept of color constancy, and the impact of simultaneous contrast. It also touches on how artists might view scenes as arrays of light to translate into paint colors, suggesting the use of a cardboard mask to isolate light perception. The exercise serves as an introduction to a course on color, focusing on object and illumination colors, their attributes, and their significance in various fields.
Takeaways
- 🎨 The script introduces an exercise using an orange-painted cardboard cube to explore three types of color perception: object colors, illumination colors, and colors of light reaching our eyes.
- 🔍 The perceived color of an object changes based on the amount of light it receives, but we tend to perceive the object's color as uniform despite varying illumination.
- 👀 Our visual system interprets colors not just as light and dark but as objects of certain colors under specific illumination, such as 'white' light.
- 📐 The exercise challenges us to consider whether we see different colors on the cube's faces or the same color under varying light intensities.
- 🖼️ The script suggests that we perceive a uniform color through different intensities of light, akin to perceiving uniform, white, and black objects under varying illumination.
- 🌈 The colors we perceive as belonging to objects are referred to as 'object colors,' while those perceived as part of the illumination are called 'illumination colors'.
- 🗿 The script encourages observing other uniformly colored objects, like a statue, to understand if we perceive them as having different colors or as the same color under different light conditions.
- 🌟 Object color perception remains relatively constant across various viewing conditions, leading us to perceive it as an inherent property of the object.
- ⚖️ The constancy of object colors is not perfect, as demonstrated by the phenomenon of simultaneous contrast, where neighboring colors influence our perception.
- 🎨 Painters may choose to see a scene as a flat array of light patches of varying intensity and color, translating these into paint colors.
- 🖌️ The script recommends using a cardboard mask with a small hole to help see the light from different areas of the cube, divorced from the context of the cube as a whole.
Q & A
What is the main purpose of the exercise with the orange cardboard cube?
-The main purpose of the exercise with the orange cardboard cube is to introduce the concept of three important kinds of colors: colors perceived as belonging to objects themselves, colors of the light falling on objects, and colors of the light reaching our eyes from objects.
How does the appearance of the cardboard cube's faces change, and what does this demonstrate?
-The appearance of the cardboard cube's faces changes depending on the amount of light they receive. This demonstrates the difference between object colors, which are perceived as belonging to the objects themselves, and illumination colors, which are perceived as varying intensities of light.
What is the significance of perceiving the cube as having similarly colored faces illuminated by different amounts of light?
-Perceiving the cube as having similarly colored faces illuminated by different amounts of light is significant because it shows our visual system's ability to perceive object colors consistently, even under varying illumination conditions.
What are the two patterns that we perceive superimposed on the same rectangle according to the script?
-The two patterns perceived superimposed on the same rectangle are the pattern of uniformly colored objects (uniform orange, white, and black) and a pattern of light and shade, which is a pattern of illumination of varying intensity.
How does our visual system perceive an object of a certain color under illumination?
-Our visual system perceives an object of a certain color under illumination by automatically presenting us with a perception of an object with a fixed, inherent property of color, illuminated by a certain color of light, typically 'white' light.
What is meant by 'object colors' and 'illumination colors' in standard scientific terminology?
-In standard scientific terminology, 'object colors' refer to the colors perceived as belonging to objects themselves, and 'illumination colors' refer to the colors perceived as belonging to the light source illuminating the objects.
How does the perception of object color remain relatively constant through wide variations of viewing conditions?
-The perception of object color remains relatively constant through wide variations of viewing conditions because our visual system perceives the object's intrinsic capacity to reflect various wavelengths of light, which is perceived as a seemingly fixed property of the object.
What is 'simultaneous contrast' and how does it affect the color perception of objects?
-Simultaneous contrast is a phenomenon where the colors of neighboring areas impact the color we perceive an object as having. It demonstrates that our perception of object color is not entirely constant and can be influenced by the colors around it.
How can painters view a scene differently from the way we normally perceive objects and illumination?
-Painters can view a scene as a flat array of patches of light of varying intensity and color, translating these colors of light reaching their eyes into colors of their paints, which is a different approach from the usual perception of objects and illumination.
What technique is suggested to help see the areas of the cube as light rather than as part of the whole cube?
-The technique suggested to help see the areas of the cube as light is to look at them through a small hole in a piece of cardboard, which isolates the light from different areas of the cube from the context of the cube as a whole.
What is the ISCC/AIC Colour Literacy Project mentioned in the script, and what is its goal?
-The ISCC/AIC Colour Literacy Project is an international initiative aimed at providing state-of-the-art educational resources that strengthen the bridges between the sciences, arts, design, and humanities, with a focus on color education.
Outlines
🎨 Understanding Object and Illumination Colours
This paragraph introduces an exercise using an orange-painted cardboard cube to explore three types of colours: object colours, illumination colours, and the colours perceived by the eye. It challenges the viewer to observe how the cube's appearance changes with varying light exposure and to consider whether the cube's faces appear differently coloured due to the light or if the cube itself appears to have uniformly coloured faces. The paragraph emphasizes that our visual system perceives objects as having a consistent colour under different lighting conditions, which is referred to as object colour. It also touches on the concept of illumination colour, which is the light's colour affecting the object's appearance. The exercise aims to deepen the understanding of how we visually interpret colours in relation to objects and light.
Mindmap
Keywords
💡Perceived Colour
💡Object Colours
💡Illumination Colours
💡Visual Perception
💡Simultaneous Contrast
💡Intrinsic Capacity
💡Uniform Colour
💡Pattern of Illumination
💡Colour Constancy
💡Context
Highlights
Introduction to the perception of three important kinds of colors: object colors, illumination colors, and colors perceived by the light reaching our eyes.
Using a uniformly painted cardboard cube as an example to demonstrate how the appearance of color changes with varying light.
The perceived color of the cube is darker on the face turned away from the light, indicating the influence of illumination on color perception.
The importance of considering not just the flat array of colors but the perception of objects with inherent colors under specific illumination.
The visual system's automatic presentation of objects with certain colors under specific illumination, like 'white' light.
Definition of object colors and illumination colors in scientific terminology.
Observing uniformly-colored objects to understand the perception of object colors under varying illumination.
The perception of an object's intrinsic capacity to reflect light wavelengths as object color.
The relative constancy of object colors through wide variations of viewing conditions.
The impact of simultaneous contrast where neighboring areas' colors influence the perceived color of an object.
The ability to deliberately see a scene as a flat array of light patches of varying intensity and color.
Using a cardboard mask to help perceive areas of the cube as light, separating them from the context of the cube.
The influence of the new context, especially the brightness of the card, on the perceived colors of light.
Continuation of the course with a detailed look at the attributes of object and illumination colors, their interrelationships, and importance.
Introduction of the ISCC/AIC Colour Literacy Project and its mission to provide educational resources bridging sciences, arts, design, and humanities.
Transcripts
A good but neglected place to start a course on colour is to ask what kinds of things we perceive
as having colours. In this short video I’ll describe a simple exercise I use to introduce
three important kinds of colours, colours perceived as belonging to objects themselves,
to the light falling on objects, and to the light reaching our eyes from objects.
For this exercise I’ll refer to a cardboard cube painted all over with the same orange paint,
but you could adapt these instructions for any uniformly coloured object. Examine the
cube and observe how the appearance of each face changes depending on the amount of light
it receives and think carefully about to how best to describe these changes.
One common answer is that the “perceived colour” of the cube is darker on the face turned away from
the light, and certainly the light from this face would match the light from a darker coloured chip
under a given level of illumination. But it would be missing something very important
about visual perception to leave it at that. Looking again at the actual cube,
ask yourself: Do you perceive the cube itself to have different-coloured faces, or do you perceive
the cube to have similarly coloured faces illuminated by different amounts of light?
I’d argue that in this image we perceive uniform orange, white and black coloured objects
in the arrangement shown top right, and also a pattern of light and shade, that is,
a pattern of illumination of varying intensity, as shown bottom right.
Notice that we perceive these two patterns superimposed in the same rectangle, [] as
though we perceive the colours belonging to the objects through the illumination.
When we perceive an object visually, our visual system doesn’t just present us with
a flat array of lighter and darker colours like a photograph, it automatically presents
us with a perception of an object of a certain colour under illumination of a certain colour,
in this case “white” light. In standard scientific terminology, these colours perceived as belonging
to objects and to illumination are called object colours and illumination colours respectively.
You might like to look at other uniformly-coloured objects and make similar observations. For
example, do you perceive this statue to be made of light and dark marble,
or do you perceive it to be white marble under varying intensities of illumination?
The colour we perceive as belonging to an object, through varying illumination,
is the way in which we perceive the object’s intrinsic capacity to reflect the various
wavelengths of light. This object colour perception remains relatively
constant through wide variations of viewing conditions, and as a result
we tend to perceive it to be a seemingly fixed, inherent property of the object.
However, this constancy of object colours is not perfect. In simultaneous contrast, for example,
the colours of the neighbouring areas impact the colour we perceive an object as having.
Finally, while we would normally perceive this scene as objects and illumination,
we can also deliberately see it as a flat array of patches of light of varying intensity and
colour. As painters we might view it in this way and translate these colours of light reaching our
eyes into colours of our paints. If this is not immediately clear,
look at the various areas of the cube through a small hole in a piece of cardboard to help you
to see these areas as light. The carboard mask shows you the light reaching your eye
from the different areas of the cube out of the context of the cube as a whole.
As always though, the colours of this light you perceive will be influenced the new context,
especially how bright the card appears. Having used the orange cube exercise to
introduce these three important kinds of colours at the start of my course,
I continue the first session with a detailed look at the various attributes of colours of objects
and colours of lights, their interrelationships and importance, again making use of the
orange cube along with other illustrations. Stay tuned for many more colour exercises like
this to be posted very soon on the website of the ISCC/AIC Colour Literacy Project,
an international initiative “to provide state-of-the-art educational resources
that strengthen the bridges between the sciences, arts, design and humanities”.
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