Colorants daylight fluorescent

The primary manufacturers of daylight-fluorescent pigment at the present time are Dane and Co. (London) Day-Glo Color Corp. (Cleveland, Ohio) Nippon Keiko Kagaku Co. Ltd. (Tokyo) Nippon Shokubai (Osaka) Lawter Chemical Corp. (Skokie, Illinois) Radiant Color, Division of Magmder (Elizabeth, New Jersey) Sinloihi Co., Ltd. (Kamakura, Japan) and U.K. Seung (Busan, Korea). Smaller regional manufacturers are located in China, India, Russia, and Brazil. 

Whereas the eadiest fluorescent-dye pigments would last only 20 days outdoors in a screen-ink film, fade resistance has been improved to such an extent that some modem daylight-fluorescent coated panels stiU have useful color after nine months or mote in Florida sunlight in a 45° exposure tack facing south. The fluorescent layer is usually coated with an acrylic film containing a uv absorber. Indoor-accelerated exposure equipment is, of course, invaluable in the development of such systems. Better dyes and resins very likely will make possible fat mote stable coatings in the future. 

Table 4 shows daylight fluorescent pigments with approximately equivalent colors manufactured by U.S. manufacturers. In addition to the colorants listed, other colors are available such as purples and shades which are stronger and between the shades Hsted. 

In daylight the nitrophenols appeared as variously colored chromatogram zones on a pale yellow background, under long-wavelength UV light (X = 365 nm) they were et-cited to the emission of fluorescence. The associated hRj values, colors and fluorescence colors are listed in the table below ... 

Lawter colors - pUMINESCENTMATERIALS - FLUORESCENT PIGMENTS (DAYLIGHT)] (Vol 15)... 

Fluorescein is naturally colorless, until placed under UV radiation—which then causes it to fluoresce an intense green color. Other discoveries involving color soon followed, enhancing the daylight fluorescent properties of dyes. 

Figure 1. Changes in postcolor number of filter-paper sheets with 15% add-on of hemicellulose fractions derived from various pulps. For comparison, the thermal discoloration of a test sheet of groundwood pulp, gp, is shown. The initial postcolor number represents the increase in color over that of the untreated filter paper a, daylight fluorescent lamps b, black-light fluorescent lamps c, heat (90 °C and 50% rh). Key O, blank filter paper , BP A, GP V, UBP 0, chlorited UBP.

Daylight fluorescent pigments, however, are comprised of a solid state solution of fluorescent dyes in a friable polymeric resin. Once the dyes are incorporated into the resin, they are ground into a fine powder for use as a pigment or colorant. As these pigments are resinous solutions of dyes, they tend to be transparent in nature. 

Uses Dye for prod, of inks, carbon paper coatings, for dyeing natural fibers such as jute, sisal, wool dye for prod, of daylight fluorescent pigments and gloss paints in paints, varnishes colorant for seeds and crop protection agents... 

It is possible to divide these special colorants into such categories as daylight fluorescent colorants, phosphorescent colorants, and pearlescent colorants [14]. 

Color-order systems, such as the many MunseU collections available from Macbeth, have been described previously. Essential for visual color matching is a color-matching booth. A typical one, such as the Macbeth Spectrahte, may have available a filtered 7500 K incandescent source equivalent to north-sky daylight, 2300 K incandescent illumination as horizon sunlight, a cool-white fluorescent lamp at 4150 K, and an ultraviolet lamp. By using the various illuminants, singly or in combination, the effects of metamerism and fluorescence can readily be demonstrated and measured. Every user should be checked for color vision deficiencies. 

Donor and acceptor levels are the active centers in most phosphors, as in zinc sulfide [1314-98-3] ZnS, containing an activator such as Cu and various co-activators. Phosphors are coated onto the inside of fluorescent lamps to convert the intense ultraviolet and blue from the mercury emissions into lower energy light to provide a color balance closer to daylight as in Figure 11. Phosphors can also be stimulated directly by electricity as in the Destriau effect in electroluminescent panels and by an electron beam as in the cathodoluminescence used in television and cathode ray display tubes and in (usually blue) vacuum-fluorescence alphanumeric displays. 

Under long-wavelength UV light (A = 365 nm) the chromatogram zones fluoresce yellow to yellow-green, they are sometimes detectable in daylight as colored zones, too. 

Note The alternative fast blue salt BB produced the most intensely colored chromatogram zones for visual analysis in daylight, while fluorescence quenching in UV light (A = 254 nm) was greater with fast blue salt B and fast blue salt RR (Figs. 1 and 2). 

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