Human vision operates in a narrow band of the electromagnetic spectrum — the range we call visible light, from approximately 380 to 700 nanometres. This is, evolutionarily, the range most relevant to the environments we navigated as a species. It is not, forensically, the range most relevant to criminal investigation.
Biological materials — blood, saliva, sweat, skin cells — fluoresce or reflect differentially across wavelength ranges that human eyes cannot perceive. Documents altered through chemical treatment reveal their modification under specific illumination conditions. Trace evidence that is invisible to the naked eye in a well-lit room becomes strikingly apparent under narrow-band ultraviolet or near-infrared illumination.
Multispectral forensic imaging is the capability to capture this evidence — to extend documentation beyond the visible range and into the wavelengths where critical evidence categories reveal themselves.
What Multispectral Imaging Does
A multispectral imaging system captures the same scene across multiple wavelength bands. The data from each band is processed separately and in combination, producing a richer information set than any single-band capture can provide.
In forensic applications, the specific value of multispectral imaging falls into several categories.
Latent fingerprint visualisation is among the most practically significant. Latent prints — the prints left on a surface through the natural oils and moisture of the fingers — are invisible on many surfaces in normal light. They may be partially visible under oblique illumination. Under specific wavelength narrow-band illumination, they become clearly visible on surfaces where standard development techniques fail — on certain fabrics, on textured or dark surfaces, on materials where chemical development would damage other evidence.
Biological trace evidence detection uses the fluorescent properties of many biological materials under ultraviolet illumination. Traces of blood or other biological material that have been cleaned or diluted below visible detection remain detectable under appropriate UV illumination. The evidence that appears to have been removed from a scene may be documentably present under multispectral examination.
Document examination applications reveal alterations — additions, deletions, overwriting — that are invisible under visible light but apparent under infrared or ultraviolet illumination. A figure altered in a financial document, a date changed in a contract, an original handwritten entry obscured by correction — multispectral imaging can reveal all of these.
The combination of these capabilities means that a crime scene or evidence item examined with multispectral imaging yields a materially more complete evidentiary record than one examined with visible-light photography alone.
The Current State of India's Forensic Imaging Capability
India's forensic science laboratories — the Central Forensic Science Laboratory system and the state forensic science laboratories — have multispectral imaging equipment. It is imported, maintained under foreign service contracts, and calibrated according to foreign standards.
The field forensic capability — the capacity to conduct multispectral examination at a crime scene rather than in a laboratory — is limited. Field-portable multispectral imaging systems are expensive, technically complex, and sourced entirely from foreign manufacturers. The operational expertise required to use them effectively is built primarily through foreign training programmes.
This creates a specific problem in time-sensitive investigations. The ideal window for collecting many categories of trace evidence closes quickly — biological material degrades, environmental factors disturb trace deposits, and investigative activities at the scene inadvertently alter conditions. A forensic capability that exists in a laboratory in a state capital, but not in the field, may arrive at a scene after the most time-sensitive evidence window has closed.
The Case for Domestic Multispectral Imaging
The technology required to build multispectral forensic imaging systems exists within India's existing industrial base. Optics manufacturing, detector arrays, illumination systems, and image processing software — the components of a multispectral imaging system — can be sourced or developed domestically.
What has not existed is the institutional commitment to integrate these components into forensic-grade imaging systems, validate them against the evidentiary standards required for court use, and deploy them within Indian law enforcement.
The validation requirement is significant and should not be minimised. Forensic equipment used to generate evidence in court must have documented, verifiable accuracy. The calibration standards, the uncertainty bounds on measurements, and the conditions under which the equipment has been validated are all relevant to the admissibility of evidence it produces. Building a domestic multispectral imaging capability is not just an engineering problem — it is an engineering problem with a demanding validation requirement attached.
This is exactly the kind of technically demanding, high-validation requirement work that India's technology institutions have the capability to do. ISRO validates spacecraft systems to standards as demanding as any forensic validation requirement. Indian pharmaceutical companies validate manufacturing processes to international regulatory standards. The capability is there.
CIPHER addresses the multispectral imaging gap as one component of an integrated forensic and reconnaissance platform. The technical challenge is real. The dependency it addresses is more consequential. And the validation path, while demanding, follows a well-understood methodology.
India's forensic science infrastructure does not have to be defined by what it imports. The decision to build rather than buy, in this domain, is a decision about what India wants its law enforcement capability to depend on in twenty years. The right answer is clear.