Color subtractive

The mean of row G = 1.35, which is equivalent to 0% competition (a lot of color). The mean of row H = 0.07, which is equivalent to 100% competition (little color). Subtract the mean of row H from all the values obtained. If the value is minus then call it 0. This determines the 100 C0% OD competition values (i.e., the range is from 0 to 1.29 OD). Using a simple formula, the percentage of competition of the samples can be calculated. Table 13 presents the processed data with respect to subtraction of background for all data, using the following equation... 

See primary colors, additive primary colors, cie and primary colors subtractive. 

Primary colors, subtractive n. Colors of three colorants or colored materials... 

Primary Colors, Subtractive n Colors of three colorants or colored materials which, when mixed together subtractively, result in black or a very dark neutral color. Subtractive primaries are generally cyan, magenta, and yellow, the three basic colorants used in printing, for example. 

Printers use colored materials, eg, inks (qv), that absorb or subtract regions of the visible spectmm from white light. Subtractive color is usually represented by the three printer s primaries cyan, magenta, and yeUow (CMY). Cyan absorbs red light, magenta absorbs green, and yeUow absorbs blue light. 

Various methods can be used to analy2e succinic acid and succinic anhydride, depending on the characteristics of the material. Methods generally used to control specifications of pure products include acidimetric titration for total acidity or purity comparison with Pt—Co standard calibrated solutions for color oxidation with potassium permanganate for unsaturated compounds subtracting from the total acidity the anhydride content measured by titration with morpholine for content of free acid in the anhydride atomic absorption or plasma spectroscopy for metals titration with AgNO or BaCl2 for chlorides and sulfates, respectively and comparison of the color of the sulfide solution of the metals with that of a solution with a known Pb content for heavy metals. 

The first instant color photography system, introduced by the Polaroid Corp. in 1963 as Polacolor, used the transfer of subtractive dyes to a receiver sheet to produce a positive image. The incorporated dye-developers, containing a hydroquinone moiety, are soluble in the alkaline activator solution, except where silver development occurs, when they are immobilized as the quinone form. 

Subtractive dye precursors (couplers) that could be immobilized in each of the silver containing layers were sought, so that dye formation in all layers could proceed simultaneously rather than successively. The first of these to be commercialized were in Agfacolor Neue and Ansco Color films, introduced soon after Kodachrome film. These reversal working films contained colorless couplers that were immobilized (ballasted) by the attachment of long paraffinic chains. The addition of sulfonic or carboxyUc acid groups provided the necessary hydrophilicity to make them dispersible as micelles in aqueous gelatin. 

Both subtractive and additive color reproduction are utilized in instant color films. Subtractive systems include all of the instant print and large format transparency materials except Polachrome 35-mm sHde films, which are additive. 

SUBTRACT LIGHT (BLUE.WHITE) COMING FROM VIEWED TARGET -REDUCE CONTRAST, ALTER COLOR OF TARGET -INCREASE HAZE... 

The titration error will increase with increasing dilution of the solution being titrated and is quite appreciable (ca 0.4 per cent) in dilute, say 0.01 M, solutions when the chromate concentration is of the order 0.003-0.005M. This is most simply allowed for by means of an indicator blank determination, e.g. by measuring the volume of standard silver nitrate solution required to give a perceptible coloration when added to distilled water containing the same quantity of indicator as is employed in the titration. This volume is subtracted from the volume of standard solution used. 

Recently, this problem has been approached by reverting to reading the color of the bilirubin directly. This used to be called an "Icterus Index", in which the color of the serum was compared to a dilute dichromate solution (39). However, the new approach has been to use two wavelengths. This can be used in either of two different procedures. In one procedure the reading is made at the peak for bilirubin which is at 453 nm and at an isosbestic point for hemoglobin (40). The effect on the reading due to hemoglobin is subtracted from the bilirubin value. Commercial instruments based on this principle have not been successful. 

Determining Indices of Polymeric Color and Browning by Subtractive Methods... 

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