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The Most Obvious Feature Of A Signal Is Color |
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One of many optical qualities that are dependent on light |
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What Makes Color? |
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| The color of a signal depends largely on the way it absorbs light. White light is made up of the colors of the rainbow (spectral colors), and when it strikes a signal some spectral colors are absorbed. Those that are not absorbed pass though or are reflected back, giving the signal its color. | |||||||||
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How a signal absorbs light depends on its chemical composition. Glass is mostly made up of quartz sand. Because of iron content in the sand, its natural color is aqua. The darker the aqua the greater its iron content. |
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The following is a list of known additives to glass and their effect on Color. |
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| Cerium - This additive would produce yellow signals. | |||||||||
| Chromium - This additive would produce green signals. | |||||||||
| Cobalt - This additive would produce blue signals. | |||||||||
| Copper - This additive would produce blue signals. | |||||||||
| Gold - Although none have been found to date, a minute amount of this additive would produce red signals. | |||||||||
| Nickel - This additive would produce purple signals. | |||||||||
| Manganese - early decolorizing agent - Depending on the amount used, this additive would produce crystal clear to purple signals. Note: Over a period of time, with exposure to the sun's ultraviolet rays, these clear signals turn a light purple, hence the term "sun colored amethyst" .The intensity of color is depend on the amount of manganese present and or the length of time exposed to the sun. | |||||||||
| Selenium - decolorizing agent - This additive would produce clear to yellow tinted signals. | |||||||||
| Sulfur - This additive would produce amber signals. | |||||||||
| Uranium - This additive would produce yellow signals. | |||||||||
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Only two coatings are known to have been used in production |
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| Carnival - tin oxide coating - This very thin but durable coating makes iridescent orange to gold coated signals. | |||||||||
| Flashed Amber - This coating makes bright amber coated signals. | |||||||||
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Multicolored Signals |
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| A signal that consists of different-colored parts is called multicolored, Two colors being referred to as " Two-Tone " .Often the result of poorly mixed batches of colored cullet (broken glass) or quite possibly from improperly blended mixtures of color producing additives. | |||||||||
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Luster |
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| The overall appearance of a signal, its luster, is determined by the way light is reflected from it. This relates to the degree of surface smoothness and to internal reflection properties of the signal. | |||||||||
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Terms to describe luster and its degree of intensity |
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| " Dull " ........... Little light is reflected from the signal | |||||||||
| " Bright " ....... Transparent with good internal reflection properties | |||||||||
| " Vibrant " .... Transparent with great internal dispersion - reflection properties | |||||||||
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