Treatment of Dyslexia - Coloured tinted glasses

Please use our colour test below to test the potential benefit of colour. Run the cursor over the chart below and change the page background colour

 

 

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Colour of objects
The upper disk and the lower disk have exactly the same objective colour, and are in identical gray surrounds; based on context differences, humans perceive the squares as having different reflectances, and may interpret the colours as different colour categories; see same colour illusion.

The colour of an object depends on both the physics of the object in its environment and the characteristics of the perceiving eye and brain. Physically, objects can be said to have the colour of the light leaving their surfaces, which normally depends on the spectrum of the incident illumination and the reflectance properties of the surface, as well as potentially on the angles of illumination and viewing. Some objects not only reflect light, but also transmit light or emit light themselves (see below), which contribute to the colour also. And a viewer's perception of the object's colour depends not only on the spectrum of the light leaving its surface, but also on a host of contextual cues, so that the colour tends to be perceived as relatively constant: that is, relatively independent of the lighting spectrum, viewing angle, etc. This effect is known as colour constancy.

Some generalizations of the physics can be drawn, neglecting perceptual effects for now:

* Light arriving at an opaque surface is either reflected "specularly" (that is, in the manner of a mirror), scattered (that is, reflected with diffuse scattering), or absorbed or some combination of these.
* Opaque objects that do not reflect specularly (which tend to have rough surfaces) have their colour determined by which wavelengths of light they scatter more and which they scatter less (with the light that is not scattered being absorbed). If objects scatter all wavelengths, they appear white. If they absorb all wavelengths, they appear black.
* Opaque objects that specularly reflect light of different wavelengths with different efficiencies look like mirrors tinted with colours determined by those differences. An object that reflects some fraction of impinging light and absorbs the rest may look black but also be faintly reflective; examples are black objects coated with layers of enamel or lacquer.
* Objects that transmit light are either translucent (scattering the transmitted light) or transparent (not scattering the transmitted light). If they also absorb (or reflect) light of varying wavelengths differentially, they appear tinted with a colour determined by the nature of that absorption (or that reflectance).
* Objects may emit light that they generate themselves, rather than merely reflecting or transmitting light. They may do so because of their elevated temperature (they are then said to be incandescent), as a result of certain chemical reactions (a phenomenon called chemoluminescence), or for other reasons (see the articles Phosphorescence and List of light sources).
* Objects may absorb light and then as a consequence emit light that has different properties. They are then called fluorescent (if light is emitted only while light is absorbed) or phosphorescent (if light is emitted even after light ceases to be absorbed; this term is also sometimes loosely applied to light emitted due to chemical reactions).

For further treatment of the colour of objects, see structural colour, below.

To summarize, the colour of an object is a complex result of its surface properties, its transmission properties, and its emission properties, all of which factors contribute to the mix of wavelengths in the light leaving the surface of the object. The perceived colour is then further conditioned by the nature of the ambient illumination, and by the colour properties of other objects nearby, via the effect known as colour constancy and via other characteristics of the perceiving eye and brain.

 

 

B A C K G R O U N D     C O L O U R

RUN CURSOR OVER COLOUR TO CHANGE PAGE BACKGROUN COLOUR

 

Colour of objects
The upper disk and the lower disk have exactly the same objective colour, and are in identical gray surrounds; based on context differences, humans perceive the squares as having different reflectances, and may interpret the colours as different colour categories; see same colour illusion.

The colour of an object depends on both the physics of the object in its environment and the characteristics of the perceiving eye and brain. Physically, objects can be said to have the colour of the light leaving their surfaces, which normally depends on the spectrum of the incident illumination and the reflectance properties of the surface, as well as potentially on the angles of illumination and viewing. Some objects not only reflect light, but also transmit light or emit light themselves (see below), which contribute to the colour also. And a viewer's perception of the object's colour depends not only on the spectrum of the light leaving its surface, but also on a host of contextual cues, so that the colour tends to be perceived as relatively constant: that is, relatively independent of the lighting spectrum, viewing angle, etc. This effect is known as colour constancy.

Some generalizations of the physics can be drawn, neglecting perceptual effects for now:

* Light arriving at an opaque surface is either reflected "specularly" (that is, in the manner of a mirror), scattered (that is, reflected with diffuse scattering), or absorbed or some combination of these.
* Opaque objects that do not reflect specularly (which tend to have rough surfaces) have their colour determined by which wavelengths of light they scatter more and which they scatter less (with the light that is not scattered being absorbed). If objects scatter all wavelengths, they appear white. If they absorb all wavelengths, they appear black.
* Opaque objects that specularly reflect light of different wavelengths with different efficiencies look like mirrors tinted with colours determined by those differences. An object that reflects some fraction of impinging light and absorbs the rest may look black but also be faintly reflective; examples are black objects coated with layers of enamel or lacquer.
* Objects that transmit light are either translucent (scattering the transmitted light) or transparent (not scattering the transmitted light). If they also absorb (or reflect) light of varying wavelengths differentially, they appear tinted with a colour determined by the nature of that absorption (or that reflectance).
* Objects may emit light that they generate themselves, rather than merely reflecting or transmitting light. They may do so because of their elevated temperature (they are then said to be incandescent), as a result of certain chemical reactions (a phenomenon called chemoluminescence), or for other reasons (see the articles Phosphorescence and List of light sources).
* Objects may absorb light and then as a consequence emit light that has different properties. They are then called fluorescent (if light is emitted only while light is absorbed) or phosphorescent (if light is emitted even after light ceases to be absorbed; this term is also sometimes loosely applied to light emitted due to chemical reactions).

For further treatment of the colour of objects, see structural colour, below.

To summarize, the colour of an object is a complex result of its surface properties, its transmission properties, and its emission properties, all of which factors contribute to the mix of wavelengths in the light leaving the surface of the object. The perceived colour is then further conditioned by the nature of the ambient illumination, and by the colour properties of other objects nearby, via the effect known as colour constancy and via other characteristics of the perceiving eye and brain.

 

 

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