Post 162 –by Gautam Shah
A surface, is often the reason, why an object is being preferred or rejected for a use, and continues to survive in a particular setting. A user perceives the surface of a material-object in many different conditions. A surface is the most proximate and tangible part of an object. The proximity to a surface defines its visual experience whereas the tangibility refers to the mainly tactile sensorial characteristics. Texture is an important qualitative parameter of a surface definition. Textures are intimately linked to specific objects, and deviation from that is immediately registered.
Textures are part of naturally occurring objects. We also fashion new finishes by varying the textural qualities. An object acquires a specific colour ‘tinge’ as the texture affects the angle of reflection of light. The angle of perception also has similar effect. The quality of light (the spectral range) and its brightness affect the perception of texture.
- ‘There are more than 20 mathematical parameters applied to surface description, and some of the terms are: roughness, irregular features of wave, height, width, lay, and direction on the surface; camber, deviation from straightness; out of flat, measure of macroscopic deviations from flatness of a surface.’
We perceive textures through Two basic manners. Visual textures occur through variations in grades of monochrome or coloured surfaces, aided by the shape, size, direction of objects. Contour variations cause tactile textures. But without going closer to the object we perceive the textures through play of shadows and illumination. At this remote perception the texture is visual happening.
Surface texture is a roughness that can be quantified by the vertical deviations from its “ideal form”. Surface roughness is a very subjective term what is rough for some context may be perceived to be smoother for other conditions. Surface textures are perceived for their extent. Surface texture is also sensed in terms of its proximity as well as its tangibility. A brick wall may be very rough to touch but a very extensive surface may not be perceived to be so rough.
Textured surfaces have larger area, so greater reactivity with the environment. Roughness of the surfaces and have higher friction coefficient so susceptible higher wear. Surface irregularities are nucleation nodes for trapping of moisture and promote corrosion. Surface texture allows better adhesion.
Textures are created by several methods, such as:
- Removal of material >> Etching, Scraping, Roughening, Filing, Grinding, Engraving, Notching, Sculpting, Machining, Blasting, Shearing, Shaving, Singeing, Spluttering, etc.
- Addition of material >> Painting, Printing, Dyeing, Metalizing, Material deposition, Plastering, Coating, Nitriding, Carburising, Galvanizing, Gilding, etc.
- By displacement processes like contraction and expansion >> Brushing, Rubbing, Ironing, Chasing, Repousse, Forming, Hammering, Forging, Beating, Levelling, Rolling, Buffing, Washing, Bleaching, Enamelling, Surface Alloying, Denting, Forming, Re-rolling, Peening, Spinning, Twisting, Weaving, Knitting, etc.