US4260645A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Latent fingerprint detection
Assignee: HER MAJESTY IN RIGHT OF CANADA AS REPRESENTED BY SOLICITOR GENERAL OF CANADA
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Filing: 1979-01-02
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Granted: 1981-04-07
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Expires: 1999-01-02
Abstract
Abstract Latent fingerprints can be detected and visualized by application to the suspected locale, of a solution, in a volatile organic solvent of selected silver salts soluble in said solvent. Suitable salts include silver perchlorate and silver trifluoroacetate. The solution is preferably applied as a spray. This non-aqueous solution minimizes smudging, "running", warping and other damage to water-sensitive material (usually inks, dyes and/or cellulosic substrates).
Inventors
- 👤 F. Michael Kerr
- 👤 Alan D. Westland
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 21:14
CPC Classifications
B; B41; B41M; B41M3/00; B41M3/006; B41M7/00; C; C09; C09K; C09K3/00; C09K3/30
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
112 words
A method for detection and visualization of latent fingerprints where the use of aqueous media is detrimental, comprising (i) uniformly contacting the latent print area of the substrate with a non-aqueous solution comprising (a) a volatile organic solvent with unsaturation present, and (b) a silver salt soluble in said solvent, sufficient silver ions being present to visualize a latent print, the silver salt being selected from silver perchlorate, silver hexafluoroantimonate, silver hexafluorophosphate, silver tetrafluoroborate, silver trifluoroacetate, and mixtures thereof; (ii) evaporating the solvent, allowing reaction of silver ion with fingerprint material to proceed and photo-actinic effects to occur leading to visualization of the fingerprint, and (iii) preserving or recording the fingerprint outline.
Claim 2
Independent Claim
112 words
A method for detection and visualization of latent fingerprints where the use of aqueous media is detrimental, comprising (i) uniformly contacting the latent print area of the substrate with a non-aqueous solution comprising (a) a volatile organic solvent with unsaturation present, and (b) a silver salt soluble in said solvent, sufficient silver ions being present to visualize a latent print, the silver salt being selected from silver perchlorate, silver hexafluoroantimonate, silver hexafluorophosphate, silver tetrafluoroborate, silver trifluoroacetate, and mixtures thereof; (ii) evaporating the solvent, allowing reaction of silver ion with fingerprint material to proceed and photo-actinic effects to occur leading to visualization of the fingerprint, and (iii) preserving or recording the fingerprint outline.
Claim 3
Dependent Claim
16 words
The method of claim 1 wherein the solution is sprayed over the entire latent print area.
Claim 4
Dependent Claim
21 words
The method of claim 1 wherein the solvent is selected from benzene, toluene, xylene, mixed xylenes, 1-hexene, cyclohexene, and mixtures thereof.
Claim 5
Dependent Claim
12 words
The method of claim 1 wherein the fingerprint outline is recorded photographically.
Claim 6
Dependent Claim
20 words
The method of claim 1 wherein the solvent is toluene, the salt is silver perchlorate and the salt concentration 1-3%
Claim 7
Dependent Claim
54 words
A kit for the detection and visualization of latent fingerprints comprising (a) a silver salt selected from silver perchlorate, silver hexafluoroantimonate, silver hexafluorophosphate, silver tetrafluoroborate, silver trifluoroacetate and mixtures thereof, (b) volatile unsaturated organic solvent for (a), and (c) mechanical means to spray or propel the solution of (a) plus (b) onto a substrate.
Claim 8
Dependent Claim
54 words
A kit for the detection and visualization of latent fingerprints comprising (a) a silver salt selected from silver perchlorate, silver hexafluoroantimonate, silver hexafluorophosphate, silver tetrafluoroborate, silver trifluoroacetate and mixtures thereof, (b) volatile unsaturated organic solvent for (a), and (c) mechanical means to spray or propel the solution of (a) plus (b) onto a substrate.
Claim 9
Dependent Claim
18 words
The kit of claim 6 wherein the salt and solvent are packaged in the form of a solution.
Claim 10
Dependent Claim
78 words
A non-aqueous solution suitable for application to latent fingerprints for detection and visualization thereof, comprising: (a) a volatile solvent mixture of an alkanol selected from methanol or ethanol, and from about 5 to about 50% by volume of the mixture of cyclohexane; and (b) a silver salt selected from the group consisting of silver hexafluorophosphate, silver hexafluoroantimonate, silver tetrafluoroborate, silver trifluoroacetate and silver nitrate; the silver salt being present in from about 1 to about 3% by wt.
Claim 11
Dependent Claim
78 words
A non-aqueous solution suitable for application to latent fingerprints for detection and visualization thereof, comprising: (a) a volatile solvent mixture of an alkanol selected from methanol or ethanol, and from about 5 to about 50% by volume of the mixture of cyclohexane; and (b) a silver salt selected from the group consisting of silver hexafluorophosphate, silver hexafluoroantimonate, silver tetrafluoroborate, silver trifluoroacetate and silver nitrate; the silver salt being present in from about 1 to about 3% by wt.
Claim 12
Dependent Claim
65 words
A sprayable non-aqueous solution dispersed in an aerosol propellant under pressure, the solution being suitable for application to latent fingerprints for detection and visualization thereof, said solution comprising: (a) a volatile organic solvent with unsaturation present; and (b) a silver salt soluble in solvent (a) and selected from the group consisting of silver perchlorate, silver hexafluorophosphate, silver hexafluoroantimonate, silver tetrafluoroborate, silver trifluoroacetate and mixtures thereof.
Claim 13
Dependent Claim
65 words
A sprayable non-aqueous solution dispersed in an aerosol propellant under pressure, the solution being suitable for application to latent fingerprints for detection and visualization thereof, said solution comprising: (a) a volatile organic solvent with unsaturation present; and (b) a silver salt soluble in solvent (a) and selected from the group consisting of silver perchlorate, silver hexafluorophosphate, silver hexafluoroantimonate, silver tetrafluoroborate, silver trifluoroacetate and mixtures thereof.
Claim 14
Dependent Claim
21 words
The solution-propellant combination of claim 9 wherein the propellant is selected from volatile halogenated hydrocarbons, inert gases, and highly volatile hydrocarbons.
Claim 15
Dependent Claim
20 words
The solution-propellant combination of claim 9 wherein the volatile organic solvent is selected from benzene, toluene, xylenes, cyclohexene, and 1-hexene.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-04-06 | 1984-10-06 | 1985-04-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-04-06 | 1988-10-06 | 1989-04-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-04-06 | 1992-10-06 | 1993-04-07 | $7700.00 | Window Closed / Lapsed |