Claims
- 1. A method of preparing a color developing composition comprising mixing first and second solutions in an approximate 1:1 volume ratio,(I) said first solution having a pH of from about 7 to about 12.5, and comprising: (a) water, (b) a color developing agent in free base form, said color developing agent being present in said first solution in an amount of at least 0.05 mol/l, (c) at least 0.005 mol/l of an antioxidant for said color developing agent, (d) water-miscible or water-soluble hydroxy-containing, straight-chain organic solvent for said color developing agent in free base form, said organic solvent having a molecular weight of from about 50 to about 200, (e) at least 0.001 mol/l of a triazinylstilbene optical brightening agent, and (f) a first chemical base, and (II) said second solution having a pH of from about 7 to about 12.5, and comprising: (a) water, (b) a buffering agent, (c) a second chemical base, and (d) at least 0.001 mol/l of a first phosphonic acid metal ion sequestering agent.
- 2. A method of preparing a color developing composition of obtained by mixing first, second and third solutions in an approximate 1:1:0.5 volume ratio,(I) said first solution being essentially free of sulfate, magnesium and lithium ions, having a pH of from about 11.5 to about 12.5, and comprising: (a) water, (b) 4-(N-ethyl-N-2-methanesulfonylaminoethyl)-2-methylphenylenediamine sesquisulfate in free base form, said color developing agent being present in said first solution in an amount of from about 0.2 to about 0.4 mol/l, (c) from about 0.005 to about 1 mol/l of either N,N-dialkylhydroxylamine or N,N′-bis(2-methyl-2,3-dihydroxypropyl)hydroxylamine as an antioxidant for said color developing agent, (d) diethylene glycol, ethylene glycol or dipropylene glycol, (e) at least 0.005 mol/l of a triazinylstilbene optical brightening agent having the structure and (f) an alkali metal hydroxide, (II) said second solution having a pH of from about 11.5 to about 12.5, and comprising: (a) water, (b) one or more carbonate buffering agents, (c) an alkali metal hydroxide or triethanolamine, (d) from about 0.005 to about 0.02 mol/l of either 1-hydroxyethylidene-1,1-diphosphonic acid or a salt thereof or morpholinomethanediphosphonic acid or a salt thereof, and (e) from about 0.01 to about 0.03 mol/l of diethylenetriaminemethylenepentaphosphonic acid or a salt thereof, and (III) said third solution having a pH of from about 11.5 to about 12.5 and comprising: (a) water, and (b) from about 0.01 to about 0.04 mol/l of either 1-hydroxyethylidene-1,1-diphosphonic acid or a salt thereof, or morpholinomethanedisphosphonic acid or a salt thereof.
- 3. The method of claim 1 wherein said first solution has a pH of from about 11.5 to about 12.5, and said second solution has a pH of from about 11.5 to about 12.5.
- 4. The method of claim 1 wherein said color developing agent is present in said first solution in an amount of from about 0.04 to about 0.4 mol/l, said antioxidant is present in said first solution in an amount of from about 0.05 to about 1 mol/l, and the molar ratio of said organic solvent to said color developing agent in said first solution is from about 10:1 to about 30:1.
- 5. The method of claim 1 wherein said antioxidant is a hydroxylamine derivative having a solubilizing group.
- 6. The method of claim 5 wherein said antioxidant is represented by the structure I: wherein R is hydrogen, an alkyl group, a hydroxyalkyl group, a cycloalkyl group or an aryl group, R1 and R2 are independently hydrogen, hydroxy, an alkyl group, or a hydroxyalkyl group, or R1 and R2 together represent the carbon atoms necessary to complete a 5- to 8-membered carbocyclic ring structure, X1 is —CR2(OH)CHR1—, X2 is —CH1CR2(OH)—, and m, n and p are independently 0 or 1.
- 7. The method of claim 1 wherein said organic solvent is an alcohol or a glycol.
- 8. The method of claim 7 wherein said organic solvent is ethylene glycol, diethylene glycol, triethylene glycol, ethanol or benzyl alcohol.
- 9. The method of claim 1 wherein said first chemical base is an alkali metal hydroxide.
- 10. The method of claim 1 wherein said first phosphonic acid metal ion sequestering agent is a diphosphonic acid or a salt thereof.
- 11. The method of claim 10 wherein said first phosphonic acid metal ion sequestering agent is either a hydroxyalkylidene diphosphonic acid or a salt thereof, or morpholinomethanediphosphonic acid or a salt thereof.
- 12. The method of claim 1 wherein said second solution further comprises at least 0.001 mol/l of a second phosphonic acid metal ion sequestering agent that is a polyaminopolyphosphonic acid or salt thereof having at least five phosphonic acid groups.
- 13. The method of claim 1 wherein neither said first solution nor said second solution comprises purposely added lithium or magnesium ions.
- 14. The method of claim 1 wherein said buffering agent is a carbonate.
- 15. The method of claim 1 that is prepared by further mixing with said first and second solutions, a third solution having a pH of from about 7 to about 12.5 and comprising one or more of the same components as defined for said second solution.
- 16. The method of claim 15 wherein said third solution comprises water and at least one phosphonic acid metal ion sequestering agent.
- 17. The method of claim 1 wherein said antioxidant is a substituted or unsubstituted mono- or dialkylhydroxylamine.
CROSS-REFERENCE TO RELATED APPLICATION
This is a Divisional of pending U.S. Ser. No. 09/586,240 filed Jun. 2, 2000 which in turn, is a divisional of U.S. Ser. No. 09/506,944 filed Feb. 18, 2000, now U.S. Pat. No. 6,136,518.
Another divisional application of U.S. Ser. No. 09/506,944, that is U.S. Ser. No. 09/851,890 filed May 9, 2001, is also pending.
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