Shades and Shadows

Natural or environmental perspective includes view-point geometries, or naturally occurring optical effects such as projection of light-beams, shadows/outlines, line-of-sight problems, translucency/ reflection/colour effects, astronomical, atmospheric, underwater optics, etc; environmental perspective includes (aspects of) human-designed vistas (e.g., architecture, gardens, etc.).

The perspective of shades and shadows (somtimes called light and shade perspective) is a subcategory of environmental perspective; and involves a range of natural optical and geometrical factors as explained below. The so-called perspective of shades can also refer to the use of perspective to create images of shades and perspective of shades / shadows.

Relievi-perspective or relievo perspective is another terms: Technique of modelling a form in the round by the treatment of tones of the surface. This is not quite the same as chiaroscuro, or treatment of light and dark which does not look at directions, shadows or surface textures etc. Rilievo is more subtle and assumes a single dominant light source supplemented by reflections from the same source into shadows.

Yet anotehr name for this form of perspective, is sciagraphic perspective: Sciography, also spelled sciagraphy or skiagraphy, is a branch of the science of perspective dealing with the projection of shadows, or the delineation of an object in perspective with its gradations of light and shade.

Skiagraphic perspective: The art of projecting shadows of objects from a luminous body such as the sun, candle, torch etc.

Solar perspective: Due to the daily rotation of the earth, combined with the tilted rotation axis of the earth, the sun appears to sweep in a wide arc across the daytime sky. Plus a seasonably variability in this arc happens due to the so-called ecliptic (or imaginary plane that contains the earth’s varying orbit around the sun), whereupon the sun casts varying length shadows on a sundial, due to both local time and day of the year. Overall the height of the sun at midday varies as seasons change; and these changes are known as solar perspective.

Lighting

In relation to perspective, the ways that light is absorbed by, and reflects from, surface structures present in a spatial reality is a key depth/shape/position indicator or cue. It is incumbant on the budding perspectivist to undertand related processes and to helps us undertand the nature of perspective images, in and of themselves.

Lighting also relates to the so-called the perspective of relief, a tform of perspective that fascinated Leonardo da Vinci, and that he employed to such remarkable affect in his darwings and paintings. Wherfeby, Leonardo studied how spatial objects/scenes have geometry that protrudes and recedes from the surface of bodies; and he related these effects to the perspective of shadows, light and shade, surface reflections, and degradation of form or angle of view or shape grammars, etc

Visible light is electromagnetic radiation that can be perceived by the human eye. Visible light spans the visible spectrum and is usually defined as having wavelengths in the range of 400– 700 nanometres (nm), corresponding to frequencies of 750–420 terahertz. The visible band sits adjacent to the infrared (with longer wavelengths) and the ultraviolet (with shorter wavelengths), called collectively optical radiation.

In optics, a pencil or pencil of rays, also known as a pencil beam or narrow beam, is a geometric construct used to describe a beam or portion of a beam of electromagnetic radiation or light, typically in the form of a cone or cylinder, but it can also be a parallel beam of light as well. In optics, the focusing action of a lens is often described in terms of pencils of rays. In addition to conical and cylindrical pencils (with axial symmetry), optics deals with astigmatic pencils as well.

Lighting, of both the natural and artificial kinds, plus their various representations in artworks, film, computer games, etc., can lead to a great variety of complex visual effects, whereby the different types of lighting can provide readily accessible information on the spatial structure(s) present in a scene. As part of this process, lighting offers unique depth-cues that can allow an observer to estimate the location, size, shape, projected direction, and hence depth, of spatial objects.

We can identify at least 7 types of lighting as follows:

Direct lighting: Focuses light on a specific spatial area. Examples of direct lighting include sunlight shining on trees and a lake, trees casting shadows, or a spotlight shining on a theatre stage.
Indirect lighting: Spreads light over a larger area by directing it towards/through a reflective/diffusing surface. Indirect lighting is dimmer and less intense than direct lighting. Chandeliers with lampshades are an example of indirect lighting, and also sunlight passing through a cloudy sky.
Semi-direct lighting: A combination of direct and indirect lighting, with most of the light directed in a forward direction (relative to the light source) and a smaller portion reflected indirectly (from surface features). Wall sconces with an opalescent glass globe is an example of semi- direct lighting.
General diffuse lighting: A combination of direct and indirect lighting that diffuses light evenly across a spatial scene.
Cove indirect lighting: Cove lighting is a type of indirect lighting built into ledges, recesses, or valances in a ceiling or high on the walls of a room. It directs light up towards the ceiling and down adjacent walls. Cove lighting is also used in cinematography, and involves creating a circular or wrap-around light effect by shining lights onto an unbleached muslin fabric, allowing for a more natural, diffused illumination.
Top lighting: A common type of direct lighting that emanates from the sun and/or an elevated light source. This type of lighting is a common situation, and we humans are adept at correctly interpreting the shadows made by spatial objects lit from above.
Transparent throughput lighting: A type of direct but reduced intensity lighting whereby a strong light source passes through a semi-transparent object and can illuminate and cast shadows on forward objects.

Shadows

Sahdow perspective refers to an environmental perspective scenario when parallel light (e.g sunlight) falls onto a masking object (for example tree branches); whereupon a shadow outline is projected onto a picture surface (for example the ground).

Shadows by artificial light: Refers to the projection of shadow outlines by a spotlight beam, whereupon a shadow outline is projected onto a picture surface (for example the ground or a wall).

Shadows are dark areas that form when an object blocks sunlight. The shape of a shadow depends on the shape of the object and the surface it falls on.

Principles

Light travels in a straight line: Light can’t bend around objects very well, so it can’t reach the surface on the other side.
The distance between the light source and the object: The closer the light source is to the object, the larger the shadow.
The angle of the light: The angle at which light hits an object affects the shape and size of the shadow.How shadows change throughout the day

How shadows change throughout the day

Early morning and evening: Shadows are longest when the Earth is further from the sun.
Around noon: Shadows are shortest when the sun is directly overhead.
Cloudy days: Shadows are softer and blurred because clouds spread out the sunlight.

Shadows in art

When painting shadows in sunlight, you can observe the shape, color temperature, and local color of the surface.
Youcanstartwithamid-tonecolorasabase,thenaddmorecolor,darken,orlightenasneeded.

Sahdows (1)

1. Sun is behind the picture plane, object is in-front

Projected shadow image of object is cast forwards away from viewpoint.

2. Sun and object are in-front the picture plane

Projected shadow image of object is cast backwards towards the viewpoint.

Shadows (2)

Sun’s rays arrive at the obscuring object and picture plane parallel to one another. An undistorted shadow outline of an object is projected onto a picture surface (for example the ground).

Theory of Shadows

The “Theory of Shadows” in the context of drawing and art focuses on understanding how shadows are formed and how they relate to the light source, object, and vanishing point(s), allowing artists to accurately depict a three-dimensional space.

Light Source and Shadows

Light travels in straight lines: Shadows are formed when light is blocked by an object,creating a dark area where light cannot reach.
Shadows are a direct response to the light: The shape, size, and direction of a shadow depend on the angle, intensity, and position of the light source.
Single Light Source: When a single light source illuminates an object, the shadow produced is called a “cast shadow”.
Understanding the Basics: Artists need to understand the basic principles of perspective and how shadows relate to the light source to accurately depict shadows in their artwork.

Perspective and Shadows

• Shadow vanishing points: Shadows can form vanishing points; but they may involve different projection rules depending on whether the light source is natural (ie the sun/ moon) or artificial (candle, electric light), and the optical results will depend upon the position of light source, object and observer.

Key Points

Light Source: Identify the location and direction of the light source.
Vanishing Point: Determine the vanishing point for the shadows based on the light source’s position.
Shadow Projections: Project the shadows from the object towards the vanishing point.
Artistic License: While understanding the principles of shadow projection is important,artists can also use artistic license to create visually appealing and expressive shadows.

Shadow Vanshing Point

In making a perspective drawing, the “shadow vanishing point” is the point where lines representing cast shadows appear to converge, similar to how lines in a scene converge to a vanishing point in traditional perspective.

Explanation

Principle: Imagine a light source and an object casting a shadow. Lines from the light source, through the top and bottom of the object, and then to the shadow’s edge, will converge at the shadow vanishing point.
Finding the shadow vanishing point: The shadow vanishing point is found by drawing a line straight down from the light source until it intersects the horizon line (or eye level).
Importance: Understanding the shadow vanishing point helps artists accurately depict cast shadows in perspective, creating a more realistic and convincing representation of three-dimensional space.
Relationship to light source: The shadow vanishing point is vertically aligned with the light source. Patently the shadow structure will depend upon whether the light source is natural (ie the sun/moon) or artificial (candle, electric light), and the optical results will also depend upon the position of light source, object and observer.
Shadows are not haphazard: They follow the same rules of perspective as other objects in a drawing.

A “vanishing point of shadows” refers to the point on the horizon line in perspective drawing where all parallel edges of a shadow appear to converge as they recede into the distance, essentially acting as the focal point for where all shadows cast by an object seem to disappear; it is determined by the position of the light source relative to the viewer and the horizon line. Here we are assuming shadows cast on the ground plane

Key points about the vanishing point of shadows:

• Light source is key: The location of the light source directly influences where the shadow vanishing point will be on the horizon line.
• Perspective drawing principle: Just like with regular vanishing points, the shadow vanishing point is used to accurately depict how shadows would appear in a three- dimensional scene.
• Finding the shadow vanishing point: To locate the shadow vanishing point, draw a line straight down from the light source to the horizon line; where this line intersects the horizon is the shadow vanishing point.

N.B. The discussion above assumes shadows projected onto the ground plane. For real-world objects, light sources, and shadows cast on surfaces located at any position/angle; then the shadows can form of any shape and with vanishing points towards in any direction.

See: central perspective, linear perspective, diminution of size, perspective of recession, converging parallels, perspective of convergence, horizon line, central or primary vanishing point, appearing point, vanishing point, illumination, shadow.

Conclusion

Perspective prescribes how a spatial object’s/scene’s visual features appear from a particular location and angle-of-view, distance, scale, etc; and according to a specific observation scenario. Visual features include points, lines, plane figures, solid shapes, shades, shadows, reflections, translucency, colour, texture, size, etc. The projected and/or visual appearance of said visual features is determined and/or exhibited according to the theory/principles/ phenomena of a specific type (class/category/form) of visual/optical/technical perspectiv