Forensics age dating ink flirten kostenlos Freiburg im Breisgau

Posted by / 23-Jul-2017 06:50

This explains the origin of the name blue-black fountain pen ink. This ink is insoluble in water and cannot be effectively erased by abrasion.The most popular fountain pen ink (developed in the 1950s) consists of an aqueous solution of synthetic dyes.Red, green, yellow and other colored chelated dyes are now used for various colored ballpoint inks.Pressurized ballpoint inks were developed about 1968.

This is done by: (1) comparing the rates and extents of extraction of questioned and known dated inks in organic solvents by thin-layer chromatography (TLC) densitometry; (2) comparing changes in dye concentrations by TLC and TLC densitometry; and (3) comparing the volatile ink components by gas chro-matography-mass spectrometry (GC-MS).

The most modern inks of this type contain pigmented dyes, such as copper phthalocyanine (introduced in about 1953) which makes these inks much more permanent.

The ballpoint pen was developed in Europe about 1939 and was initially distributed in Argentina about 1943.

The composition is basically the same, but this ink does not become fluid until disturbed by the rotation of the ball point in the socket.

Cartridges containing this ink are under the pressure of nitrogen or some other inert gas.

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These pens contain a pressurized feed system instead of gravity flow.