阅读说明：本技术 一种潜指纹显现棉片及应用 (Latent fingerprint showing cotton piece and application ) 是由 范丽娟 樊智楠 马荣梁 于 2019-10-09 设计创作，主要内容包括：本发明公开了一种潜指纹显现棉片及应用。以无纺布为基材,浸泡于指纹显现剂中,经吸附后基材呈湿润状,负载指纹显现剂,得到一种潜指纹显现棉片。将棉片浸泡于显现剂中制得显现棉片,可通过控制显现剂的量,得到不会污染潜指纹客体的显现棉片；将显现棉片覆盖于含有潜指纹的客体上,揭下棉片后将客体自然干燥,即可在与显现剂相匹配的光源下观察到指纹纹路,适合拍照记录。本发明提出的棉片显现潜指纹的方法显影效果佳,便携,操作简便,显影时间短；适用范围广,可制备成不同大小的载有不同显现剂的棉片；可重复使用,适合于刑侦现场操作和工业化生产。(The invention discloses a latent fingerprint appearing cotton piece and application thereof. The cotton sheet with fingerprint showing effect is prepared through soaking non-woven fabric as base material in fingerprint showing agent, adsorbing to form wet base material, and loading fingerprint showing agent. Soaking the cotton sheet in a developing agent to prepare a developing cotton sheet, wherein the developing cotton sheet which does not pollute the latent fingerprint object can be obtained by controlling the amount of the developing agent; the revealing cotton piece is covered on the object containing the latent fingerprints, the object is naturally dried after the cotton piece is removed, and fingerprint lines can be observed under a light source matched with the revealing agent, so that the revealing cotton piece is suitable for photographing and recording. The method for displaying the latent fingerprints on the cotton sheets has the advantages of good developing effect, portability, simplicity and convenience in operation and short developing time; the application range is wide, and the cotton sheets with different sizes and carrying different developing agents can be prepared; can be repeatedly used, and is suitable for criminal investigation field operation and industrial production.)

1. A latent fingerprint revealing cotton sheet characterized in that: it uses non-woven fabric as base material, and soaks in fingerprint developing agent, after adsorption, the base material is wet, and loaded with fingerprint developing agent so as to obtain the invented cotton sheet with latent fingerprint.

2. A latent fingerprint revealing cotton sheet according to claim 1 wherein: the amount of the fingerprint developing agent adsorbed on the base material is 5 mu L/cm²～50μL/cm²。

3. A latent fingerprint revealing cotton sheet according to claim 1 or 2, wherein: the fingerprint developing agent comprises a occult blood fingerprint developing agent, a sweat fingerprint developing agent and an oil fingerprint developing agent.

4. A latent fingerprint revealing cotton sheet according to claim 1 wherein: it includes single fingerprint, multiple fingerprints or large area latent fingerprint showing cotton piece.

5. A latent fingerprint revealing cotton sheet according to claim 1 wherein: the latent fingerprint showing cotton sheet is sealed and stored in a dark place.

6. Use of a latent fingerprint revealing cotton sheet according to claim 1 wherein: it is used for fingerprint display of occult blood fingerprint, latent sweat fingerprint and latent oil fingerprint.

7. Use of a latent fingerprint revealing cotton sheet according to claim 6 wherein: the application of the method to the visualization of the occult blood fingerprint comprises the following steps:

(1) fixing fresh occult blood fingerprint blood: immersing the object loaded with the fresh occult blood fingerprint into absolute ethyl alcohol, soaking for 2-3 min, taking out and naturally drying; or standing the object loaded with the fresh occult blood fingerprint in a cool and dry place for more than 12 hours;

(2) flatly covering the object loaded with the occult blood fingerprint revealing agent with an occult blood fingerprint revealing cotton piece, slightly pressing to enable the cotton piece to be fully contacted with the object, and standing for 2-5 min; the object loaded with the occult blood fingerprint is the fresh occult blood fingerprint or the old occult blood fingerprint processed in the step (1);

(3) and (3) smoothly taking off the cotton sheet from the object, drying, and shooting under the illumination condition matched with the developing agent to obtain the occult blood fingerprint developed by the developing cotton sheet.

8. Use of a latent fingerprint revealing cotton sheet according to claim 6 wherein: the method is applied to the visualization of the latent sweat fingerprint or the latent oil grease fingerprint and comprises the following steps:

(1) flatly covering a latent fingerprint revealing cotton sheet loaded with a sweat latent fingerprint or oil-submerged grease fingerprint revealing agent on an object loaded with a sweat latent fingerprint or oil-submerged grease fingerprint, slightly pressing to enable the cotton sheet to be fully contacted with the object, and standing for 2-5 min;

(2) and (3) smoothly taking off the cotton sheet from the object, drying, and shooting under the illumination condition matched with the developing agent to obtain the latent sweat fingerprint or the grease fingerprint developed by the developing cotton sheet.

Technical Field

The invention relates to a fingerprint display method, in particular to a display cotton piece based on a non-woven fabric substrate and application thereof, belonging to the technical field of trace detection.

Background

With the development of an Automatic Fingerprint Identification System (AFIS), fingerprints, which are a non-negligible part of fingerprint identification because they are commonly found in a scene and invisible to the naked eye, are of great interest to researchers as one of important material evidences in criminal investigation and forensic science.

Latent fingerprints can be classified into occult blood fingerprints, sweat latent fingerprints and oil fingerprints according to the components of the latent fingerprints. One of the most commonly used methods for visualizing occult blood fingerprints at present is a chemical enhancement method, i.e. an appropriate chemical agent is selected and an appropriate operation method is combined for visualizing occult blood fingerprints. Today, many chemical agents have been demonstrated to be effective in directly visualizing latent fingerprints and greasy fingerprints of sweat, but research into visualizing the operating methods is not complete. The dip coating method, the dipping method, the spray coating method, etc., which are mainly used at present, have more or less limitations, such as the need for pretreatment and/or post-treatment of fingerprints, inconvenience in carrying and storing reagents, long development period, etc. In addition, the dipping method is only suitable for small-sized objects, the dipping method may cause uneven appearance and damage to fingerprint patterns, and the spraying method may cause injury to operators due to volatilization of a large amount of solvent. Due to the limitations of the existing methods, the operational methods available for the chemical enhancement method to reveal latent fingerprints have not been able to meet the enormous demands of practical applications at actual crime scenes to date. Therefore, it is of great significance to develop a latent fingerprint presentation method which is simple, efficient, portable and wide in application range.

Cotton sheets based on nonwoven fabric substrates have excellent water absorption and water release properties and have been widely used for wiping and removing makeup of cosmetics. However, the latent fingerprint wet-face sheet which is convenient to carry, simple to operate and good in developing effect is not reported by using the non-woven fabric substrate as a carrier of the developing agent, particularly for a latent fingerprint field which is invisible to naked eyes.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides the latent fingerprint showing cotton piece which has the advantages of good developing effect, portability, simple and convenient operation, wide application range, reusability and suitability for criminal investigation field operation and industrial production and application thereof.

The technical scheme for realizing the aim of the invention is to provide a latent fingerprint showing cotton sheet, which is obtained by taking non-woven fabrics as a base material, soaking the non-woven fabrics in a fingerprint showing agent, adsorbing the non-woven fabrics to ensure that the base material is in a wet state and loading the fingerprint showing agent.

The latent fingerprint appearing cotton sheet provided by the technical scheme of the invention has the preferable scheme that:

the amount of the fingerprint developing agent adsorbed on the base material is 5 mu L/cm²～50 μL/cm²。

The fingerprint developing agent comprises a occult blood fingerprint developing agent, a sweat fingerprint developing agent and an oil fingerprint developing agent.

The latent fingerprint showing cotton piece comprises a single fingerprint, a plurality of fingerprints or a large-area latent fingerprint showing cotton piece.

The latent fingerprint showing cotton sheet is sealed and stored in a dark place.

The technical scheme of the invention also comprises the application of the latent fingerprint revealing cotton piece, which is used for carrying out fingerprint revealing on latent blood fingerprints, latent sweat fingerprints and latent grease fingerprints.

The latent fingerprint developing cotton piece is applied to developing latent blood fingerprints and comprises the following steps:

(1) fixing fresh occult blood fingerprint blood: immersing the object loaded with the fresh occult blood fingerprint into absolute ethyl alcohol, soaking for 2-3 min, taking out and naturally drying; or standing the object loaded with the fresh occult blood fingerprint in a cool and dry place for more than 12 hours;

(2) flatly covering the object loaded with the occult blood fingerprint revealing agent with an occult blood fingerprint revealing cotton piece, slightly pressing to enable the cotton piece to be fully contacted with the object, and standing for 2-5 min; the object loaded with the occult blood fingerprint is the fresh occult blood fingerprint or the old occult blood fingerprint processed in the step (1);

(3) and (3) smoothly taking off the cotton sheet from the object, drying, and shooting under the illumination condition matched with the developing agent to obtain the occult blood fingerprint developed by the developing cotton sheet.

The latent fingerprint revealing cotton piece is applied to revealing latent fingerprint of sweat or latent grease fingerprint, and comprises the following steps:

(1) flatly covering a latent fingerprint revealing cotton sheet loaded with a sweat latent fingerprint or oil-submerged grease fingerprint revealing agent on an object loaded with a sweat latent fingerprint or oil-submerged grease fingerprint, slightly pressing to enable the cotton sheet to be fully contacted with the object, and standing for 2-5 min;

(2) and (3) smoothly taking off the cotton sheet from the object, drying, and shooting under the illumination condition matched with the developing agent to obtain the latent sweat fingerprint or the grease fingerprint developed by the developing cotton sheet.

The latent fingerprint developing agent is loaded on the non-woven fabric base material to prepare the developing cotton sheet, and an unexpected effect is generated, which is mainly embodied in the following aspects: 1. the method is used for displaying latent fingerprints, the operation process is convenient and simple, and the objects loaded with the latent fingerprints do not need to be subjected to post-treatment; 2. the dosage of the developing agent can be accurately controlled in advance, and the waste caused by field operation is reduced as much as possible; 3. the size and the position of the fingerprint object are not strictly limited, so that the on-site investigation of the latent fingerprint is easier; 4. due to the use of the revealing cotton piece, the amount of the reagent which is vaporized into the air and/or remained in the air is greatly reduced, and the pollution to the environment and the harm to the health of a user are greatly reduced; 5. the cotton piece soaked by the developing solution is put into a container or a bag for sealing, so that the cotton piece is convenient to carry and store for a long time, and can be repeatedly used.

Compared with the prior art, the invention has the beneficial effects that:

1. the preparation method of the revealing cotton piece provided by the invention has no special material requirement on the base material of the cotton piece, only needs the texture of the revealing cotton piece to be soft, does not damage the fingerprint pattern, and has excellent water absorption and water release performance.

2. The method for showing the latent fingerprints on the cotton piece is suitable for all the situations that the latent fingerprints are shown by using a chemical reagent, the shown fingerprint patterns are clear, the showing agent is uniformly distributed on fingerprint lines, and no showing agent residue exists on the surface of an object background.

3. The latent fingerprint showing method provided by the invention is convenient and simple in operation process, and does not need pretreatment and/or post-treatment.

4. The showing cotton sheet provided by the invention is put into a sealed lightproof bag or container, is convenient to carry and can be stored for a long time.

5. The revealing cotton sheet provided by the invention can accurately control the dosage of the revealing agent in advance, and reduce the waste caused by field operation.

6. The latent fingerprint showing method provided by the invention has no strict limitation on the size and the position of the fingerprint object, and can cope with various conditions of criminal scene investigation.

7. The developing cotton sheet provided by the invention can lock the developing agent to a certain degree, so that the amount of the reagent evaporated into the air and/or remained in the air is reduced, and the environmental pollution and the harm to the health of a user are reduced to a great extent.

8. The revealing cotton sheet based on the non-woven fabric base material can be repeatedly used. If the developing cotton piece (2 cm multiplied by 3 cm) soaked by 150 mu L of Coomassie blue solution can effectively develop at least 5 latent blood fingerprints.

Drawings

FIG. 1 is a digital photograph and an optical microscope photograph of a cotton sheet for developing a base material, a cotton sheet for developing adsorbing a developer, and a cotton sheet for developing in example 1 of the present invention; wherein, a is a digital photograph of the substrate, b is a digital photograph of the cotton piece with the Coomassie blue developing agent adsorbed thereon, and c is an optical microscope photograph of the cotton piece with the Coomassie blue developing agent adsorbed thereon.

FIG. 2 is a comparison graph of latent fingerprint appearance provided in example 2 of the present invention, a₁～a₄Respectively showing the effect of developing cotton sheets soaked with amino black 10B, coomassie blue, eosin and acid fuchsin on the latent blood fingerprint on the object on the cover glass, B₁～b₄To show the effect of the latent blood fingerprints on the coverslip objects by dip coating using aminoblack 10B, Coomassie blue, eosin and acid fuchsin visualization agents, respectively, c₁～c₄The figure shows the effect of developing the latent blood fingerprint on the object on the cover glass by dip coating using aminoblack 10B, Coomassie blue, eosin and acid fuchsin developing agents, respectively, d₁～d₄The figure shows the effect of developing the latent blood fingerprint on the object on the cover glass by spraying with aminoblack 10B, coomassie blue, eosin and acid fuchsin developing agents.

FIG. 3 is a comparison graph of latent fingerprint appearance provided in example 3 of the present invention, a₁～a₄Respectively, developing cotton piece soaked with amino black 10B, Coomassie blue, eosin and acid fuchsin to white enamelPattern of appearance of latent blood fingerprints on the object, b₁～b₄To show the effect of occult blood fingerprints on white enamel objects by dip coating using aminoblack 10B, Coomassie blue, eosin and acid fuchsin visualization agents, respectively, c₁～c₄The effect chart is that the jet developing method is used for developing the occult blood fingerprint on the white enamel object by using aminoblack 10B, Coomassie blue, eosin and acid fuchsin developing agents respectively.

FIG. 4 is a picture of latent fingerprints of fats and oils under ultraviolet light (365 nm) after development with PPV nanoparticles, provided in example 4 of the present invention, wherein a is a development effect picture of latent fingerprints of fats and oils using development cotton, b is an effect picture developed using a soaking method, c is an effect picture developed using a smearing method, and d is an effect picture developed using a spraying method.

Detailed Description

The technical scheme of the invention is further explained by combining the drawings and the embodiment.