Basic Scarlet

Phenosafranine was the first viable desensitizer and originally appeared on the market as Pinasafrol and Desensitol. Although phenosafranine can be used alone, diluted 1 10,000 with water, a better choice for modern MQ developers is Basic Scarlet N, a combination of phenosafranine and chrysoidine, two commercially available dyes. Basic Scarlet N is more efficient than phenosafranine alone and has greater keeping properties (Formulas Miscellaneous). 

The major drawback to both phenosafranine and Basic Scarlet N is that they stain everything. They can also cause excessive fog when used with pyro developers. 

NOTE 1 Basic Scarlet N tends to shorten development times by about 10%. 

NOTE 2 A proprietary variation of Basic scarlet N, De-Tec, is available fromAntec (Resources). 

Colouring matters which are neither acid nor basic are reduced and oxidised on the cotton itself. The resistance to reduction exhibited by certain azo-colouring matters, especially those formed directly on the fibre, is overcome by addition of very small quantities of suitable colouring matters or other reducing bodies, such as indulin scarlet, alizarin or anthia-quinone, which increase the activity of the hydrosulphite. The use of anthraquinone is preferred because it does not dye cotton, while addition of it in minimal quantity to the hydrosulphite solution and slight acidification with acetic acid yields a reagent (hydrosulphite B X) which causes reduction in every case. 

American vermilion Arancio cromo Austrian cinnabar Basic chromium lead oxide (CrPb205) CCRIS 6187 Chinese red Chrome carmine, Chinese scarlet Chrome cinnabar Chrome garnet Chrome orange Chrome ruby Chromic acid, lead(2 ) salt (1 2) Chromium dilead pentaoxide Chromium lead oxide Derby red Dilead chromate oxide EINECS 242-339-9 HSDB 6185 Lead chromate oxide Lead chromate oxide (Pb2(Cr04)0) Lead chromate(IV) Lead chromate(VI) oxide Persian red Victoria red Vienna red. Pigments consisting of basic lead chromate. Red powder insoluble in H2O,... 

When a coloured object is illuminated by white light, it selectively absorbs some of the wavelengths and transmits others. The eye receives the transmitted wavelengths and summarizes them as one colour. This colour is dominated by the main wavelengths transmitted, which determine its basic hue. This hue is modified by undertones of the other wavelengths, which make it an individual shade. Thus there are many red shades some are bright, some dark some have a yellow undertone (e.g. scarlet) and some a blue one (e.g. crimson). A truly black object absorbs all the wavelengths and a truly white one, none of them. 

Brilliant cotton blue. See Acid blue 93 Brilliant fast oil yellow. See 4-Dimethylamlnobenzene Brilliant fast scarlet R. See Solvent red 1, Brilliant fast spirit yellow. See 4-Dimethylamlnobenzene Brilliant green. See Basic green 1 Brilliant green Brunswick green. See Chrome green... 

The brown aqueous solution of sodium rhodizonate (I) produces colored precipitates of basic lead rhodizonates from neutral or slightly acid lead solutions. Violet Pb(Ce0fl) Pb(0H)2 H20 is thrown down in neutral solution scarlet-red 2 Pb(C 0e) Pb(0H)2 H20 is produced from weakly acid solutions. The deep color of these lead salts probably arises from the fact that the organic anionic component contains five double bonds, as seen in II. o o... 

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