FORENSIC 4

• type of inks

  writing and printing
• other kinds of inks

  invisible, rubber stamp, copying, marking and indian inks
• writing inks are non-aqueous inks; they are used generally with steel pens
• printing inks contain pigments or dyes and a carrying liquid that spreads colors out
• invisible ink also called sympathetic inks; it cannot be seen unless heated or added a chemical to them to bring out the color and are generally used for secret writings
• copying inks found on carbon papers and typewrite ribbons
• marking inks are a specially made for woods, metal, cloth, and the like
• indian ink is a deep black ink containing dispersed carbon particles used especially in drawing and technical graphics
• synthetic dye inks any ink which consists simply of a dye in water together with necessary preservatives
• Ink differentiation is used to detect alterations, erasures, and material changes in documents
• Ink may be differentiated nondestructively with a video spectral comparator.
• Physical and chemical properties of two different inks will cause differing results when examined using the alternative light sources and filtering techniques available with VSC
• thin-layer chromatography is a destructive chemical testing used to compare formulas of ink on alleged altered documents
• wax seals were used to seal documents as protective seals of envelops to discourage tampering while in transit
• embossed seal such by a notary is a far more common type of seal; the impression is fixed in the paper by pressing it between two metal plates
• adhesive stamps, refer mostly to postal and revenue stamps; they serve primarily as a ready means of dating documents
• if the original document has been altered then a good photograph or photocopy of it could sill be examined and presented as evidence in court as secondary evidence
• photographs can be cut part so that portions to be compared are placed side by side
• faint discolorations on documents due to chemical alterations or weathering may clearly be shown through the use of photographic enhancement
• by using oblique light, paper fiber disturbances caused by such erasures can be shown and photographed
• special photography can show whether a stroke came before or after another stroke or that a paper was folded before of after a writing done on it
• photocopying is the common means of reproducing documents
• Disputed document - questioned document may also called by this name, when there is an argument over ownership
• Paper - is the material by which documents are commonly written
• graphite - is the material which enables the pencil to write