3. Forensic Photography

3. Forensic Photography Forensic Photography Role of Forensic Photographer • Produce truthful and objective images. • Represent the scene as it was found. • Produce images for measurement and analysis (accompany forensic, medical, or scientific reports). Digital Imaging • Original image preserved with redundancy. • Digital processing steps (changes) are logged. • End result is presented as an enhanced image. • May be reproduced by applying the logged steps to the original image. • Benefits: • Immediate results • Cost • Admissibility in court (passed Frye in 1996) • Security & storage • Some photos stored on internet less computers (anti-hacking). • Only certain people were allowed into the room. • Phones that no one else has access to (passcode & ID to get in). Alteration vs Enhancement • Alteration: To change what the image represents • NEVER make any alterations! • Enhancement: To make the image easier to view (changing brightness, contrast, sharpness, cropping, etc.) • Allowed as long as every enhancement is logged. Depth of Field • How much is in focus in front of and behind the subject. • Shadow DOF: Only subject is in focus (macro photography) • Blurry directly in front of and behind the subject • Long DOF: Everything in focus (crime scene photography) • In focus in front of and far behind the subject Image File Formats • RAW: Uncompressed file format (preferred for high detail images). • Evidence comparison photos • Large number of pixels • JPEG: Compressed file format (high compression will affect image detail). RAW Image (Left) vs JPEG Image (Right) • General crime scene photography • Fewer number of pixels com/watch?v=wrckVlY5vwU&list=LLs1R5Ig0knc69mYZtbpp1 • GIF, EPS, Bitmap, Pict, etc. Lighting • Fill Flash: Fills in the space of darkness • Fixes backlighting problems • Infrared Photography: Removes colored designs on items No Fill Flash (Left) vs With Fill Flash (Right) investigator.net/flashfill.html"https://www.crime-scene- • Finds gun powder residue Crime Scene Photography Kit • Cameras, normal lens (24-70 mm), wide angle lens (1424 mm), macro lens, flash, batteries (camera & flash), IR Photography Showing Gunpowder on a Black T-shirt From HYPERLINK "https://slideplayer.com/slide/57618 51/"https://slideplayer.com/slide/576 tripod, flashlight, memory cards, owner’s manuals, notebook, pen, photo scales. Important Photographs • Overview (generally in corners) (always note direction photograph was taken in photolog) • Intermediate (mid-range) • Overview/Intermediate with markers • Itemized evidence • Evidence comparison images • RAW, 90º, Photo Scale Overview Photo • Photo Log! • Never put anyone in the photo (except decedents) Special Lenses • Macro Lens: Extremely close up image of a subject (the subject fills up the whole field of view) • Have special flash for macro photography • Wide Angle Lens: Great for overview (14-24 mm, 24-70 mm) Evidence Comparison Photos Meta Data • Describe everything about the image (e.g. pixels, shutter speed) • Show where or when an image was taken • Cannot be changed easily Photo Scales • Used in Evidence Comparison Photos • The circles are used to show the angle at which the photo was taken • If < 90º, the circles will be ellipsis Alternate Light Sources • Help to see things not visible in visible light Photo Scale Scale/dp/B00236V0US"https://w