Depending on the nature of the evidence, specific forensic techniques are used. Each technique requires specific equipment or tools to collect, preserve, and analyze evidence. Fingerprint analysis (requires a camera/scanner, fingerprint powder, alternate light sources, lifting tape, etc.), questioned document analysis (requires measuring rulers and grids, a Video Spectral Comparator (VSC), a micro-spectrometer, etc.), Toxicology (requires Gas Chromatograph–Quadrupole Mass Spectrometer or GC-QMS, GC Ion Trap MS or GC-IMS, etc.), Serology (requires a DNA sequencer, microcentrifuge, stereomicroscope, etc.), firearms analysis (requires stereomicroscope, comparison microscope, GSR analyzing chemicals etc.), blood pattern analysis (camera, cotton swabs, sketchpad, etc.), etc. are all such techniques that are used when necessary.