Colour sensation is a characteristic of human experience. Nature provides a particularly vivid display of color. We use colors in many varied ways; for clothes, paints, foods, lighting, cosmetics, paper, furnishings, and for identification and security. Despite our familiarity with it, there is no simple answer to the question ‘What is color, and how do we see it?’ We understand so very little of the complex processes involved in color vision. There are three main stages in the perception of color, but each one consists of numerous complicated processes:
(1) absorption of colored light entering the eye by the sensitive cells in the retina lining the back of the eyeball;
(2) transmission of nerve impulses from the retina to the brain via the optic nerve;
(3) interpretation of these signals when they reach the visual cortex in the brain.
To understand color, some knowledge of the nature of light is essential. Light is a form of energy usually considered as being propagated at high speed in the form of electromagnetic waves.
Even though today almost all the textile industry that deals with reading color, uses a Macbeth Lightbox, they all read color differently.
A large part involved in reading color is the differences in Dye stuff by different manufacturers; ambient temperature of the room where color is being looked at; the person’s knowledge and perception of how color is mixed and a person’s perception of variation from Pantone Chip being studied and above all what light is the color being seen: daylight D50, D65, D75, daylight horizon at 2300K, incandescent, cool white fluorescent, filtered near ultraviolet, U30 (3000K), U35 (3500K) and TL84. For instance, X-Rite’s filtered tungsten/halogen SpectraLight is an extremely close match to natural daylight.
There is a generic Color Index Classification that the Textile Industry follows but each uses different dyes in the process.
For example, Indanthren Golden Yellow RK is a vat dye manufactured by BASF (Badische Anilin und Soda Fabrik). ‘Indanthren’ is the brand name used for their range of vat dyes. ‘Golden Yellow’ indicates the color and the code ‘RK’ shows that this dye is a reddish yellow and applied using a cold-dyeing method. The letter ‘R’ stands for the German word rot = red (the dye is listed as CI Vat Orange
1) and the ‘K’ comes from the German kalt = cold. On the other hand, BASF manufacture Procion Red H-E3B. ‘Procion’ is their brand name for reactive dyes for cotton. All the Procion dyes with ‘H-E’ in the code are dyes with two identical reactive groups. Reaction of the dye with the cotton occurs under hot (‘H’) conditions. The ‘3B’ in the code shows that this is a bluish red (B = blue); bluer than similar red dyes with a code B, but redder in hue than dyes with a 6B in the code. In other cases, the alphanumeric code following the name of the dye may be of little or no value to the dye user.
Thickness of fiber also plays an important role in how well the color saturates in the fabric. Cotton may be easy to dye but the thickness of fabric determines how well the color has absorbed in the fabric to give full saturation.
Dyes should covalently bond to fabrics rather than only joining to the fabric by weak intermolecular forces. But each fabric takes dyes according to the yarn density and the type of yarn, so color will read different in all cotton yarn as against if it is blended with polyester or linen or rayon.
Light Ergonomics plays an important part in color reading too. This is the relationship between the light source and the individual.
The person reading color, needs to place color properly in the same position each time.
Color cannot be looked at in a hurry, the person has to sit comfortably before the Lightbox, place both the color to be matched and the correct color next to each other.
The two should not overlap or the edges will read darker.
It is preferred that a cardboard stand be made that is a quarter in height of the lightbox.
The fabric and matching color should be place on this stand. This provides correct height and distance required for reding of color.
Ambient Temperature spikes and dips around the Lightbox can have a bearing on color visualization. If there is moisture or heat in the room, the color variation may show up. Heat or cold surrounding temperature can have the same alchemy that shows up on making color.
Warm colors advance and cool colors recede, affecting the perception of depth. This theory is based upon that fact that the eye adjusts when focusing on colors of different wavelengths. Red light waves have a longer wavelength than blue ones. An image containing both cool and warm colors would demonstrate contrast of temperature or warm/cool contrast creating more complex relationships between the color (warm colors can read cooler against a higher intensity warm colors and cool colors sometimes can advance against predominately warm palette).
Yarn Dyed fabrics that are woven in a warp and weft, where the same color is used, may show shifting hues. The play of light on the warp and weft of the weave may show deeper or lighter tints in the color, even when the two yarns are the same.
It would be best to surmise that color on Textiles has to be looked at keeping in mind the sensitivity that color offers and thereby the complexity is as good as the eye that sees it!