Christian Leborg defines concrete objects as those forms that are perceived within defined limits. These limits are called contour lines and are the strokes which define the area of a shape or form. There are three kinds of forms: geometric, organic and random. Geometric forms are shapes based on mathematical facts. Organic forms are irregular in structure and their contour lines are based on the fluidity of living organisms. Random forms are incidental. They have no definite mathematical sequencing or natural structure.
Size and color can have an impact on ones ability to determining an objects form. As Leborg points out, “If the visual transition is gradated or has small nuances in shade or hue, it is difficult to define the form.” The size of an object is a relative relationship. The size of an object is determined by its relation to other objects or its placement in a composition. If a form is too small, it may be difficult to determine if it is concrete or abstract. Color also plays a role in determining whether or not an object is concrete. Small nuances or gradation of color can cause a form to bleed or blend into the background color, thus causing it to lose its contour lines and no longer be concrete.
Like concrete objects, concrete structures are those with visible structure lines or lines which influence the forms of the objects in the structure. Visible structures can have structure lines and objects, or just structure lines. Active structures are concrete structures in which the structure lines are influencing the forms of the objects in the structure. However, a structure does not have to be visible to be active.
Eric Miller, author of the article Using Shapes in Graphic Design, goes into more depth in his discussion of shapes and the impact they have on a design. While Leborg focus more on the definition of concrete objects, Miller delves into the impact concrete objects can have on the overall connotation of a work.
Miller talks of how, “using shapes properly is one of the keys to successful graphic design. The form, color, size and other characteristics of the shapes in a layout can determine its mood and message.” The article discusses how soft, curved, and rounded shapes are perceived as more welcoming, lighthearted, and youthful than sharp, angled shapes which can connote a feeling of danger or rigidity. Miller also brings up an important point about the spaces between shapes and their impact on the overall feeling and impact of a design.
While this is just one article written by Miller, he also has a website where samples of his design work and blog posts can be found: http://www.ericmillerdesign.com. As well, there are other articles which speak into graphic design concepts found on the web address where I located the article on shapes that Miller wrote.
In this Image, the thick black line drawn around the individual petals are the contour lines. They define the petals shapes and prevent the cross-contour lines from bleeding into one another. The use of contour lines in this image make this drawing of a flower a concrete object.
This is an example of geometric form. The image above is made up of diamond shapes, which are mathematically rendered objects, and the artist has chosen to use color as contour lines to separate the shapes from one another.
An example of organic form, the above image uses line to create irregular shapes. This irregular shapes are hand drawn, which makes it organic in structure, and the use of contour lines around each shape make each form concrete objects.
Here is an example of a concrete structure found in architecture. According to Leborg, concrete structures must have structure lines that are visible or influence the form of the objects in the structure. In this image, the structure lines are both visible and influencing the form of the objects in the structure of the building.