Magnasee is a product used to visualize the

magnetic fields A magnetic field (sometimes called B-field) is a physical field that describes the magnetic influence on moving electric charges, electric currents, and magnetic materials. A moving charge in a magnetic field experiences a force perpendicular ...

recorded onto magnetic recording media such as

magnetic tape Magnetic tape is a medium for magnetic storage made of a thin, magnetizable coating on a long, narrow strip of plastic film. It was developed in Germany in 1928, based on the earlier magnetic wire recording from Denmark. Devices that use magnetic ...

diskette A floppy disk or floppy diskette (casually referred to as a floppy, a diskette, or a disk) is a type of disk storage composed of a thin and flexible disk of a magnetic storage medium in a square or nearly square plastic enclosure lined with a ...

s, and the like. The product contains very fine colloidal

iron Iron is a chemical element; it has symbol Fe () and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, forming much of Earth's o ...

in a fast-evaporating liquid such as

naphtha Naphtha (, recorded as less common or nonstandard in all dictionaries: ) is a flammable liquid hydrocarbon mixture. Generally, it is a fraction of crude oil, but it can also be produced from natural-gas condensates, petroleum distillates, and ...

fluorocarbon Fluorocarbons are chemical compounds with carbon-fluorine bonds. Compounds that contain many C-F bonds often have distinctive properties, e.g., enhanced stability, volatility, and hydrophobicity. Several fluorocarbons and their derivatives are ...

s. The liquid is first agitated vigorously to disperse the iron. It may then be carefully poured over the magnetic media of, in the case of tape, the tape may be dipped into the open container of liquid. The iron adheres between the

magnetic domain A magnetic domain is a region within a magnetic material in which the magnetization is in a uniform direction. This means that the individual magnetic moments of the atoms are aligned with one another and they point in the same direction. When c ...

s of the media, allowing the user to see where these magnetic domains have been written. Allowing the carrier liquid to evaporate allows very close visualization of the domains. Various faults in the magnetic recording process could then be visually detected. These included: * Track mis-alignments including gross

azimuth An azimuth (; from ) is the horizontal angle from a cardinal direction, most commonly north, in a local or observer-centric spherical coordinate system. Mathematically, the relative position vector from an observer ( origin) to a point ...

errors * Missing (unrecorded) tracks * Failures of the erasure system * Lift-off of the media from the recording head(s) * After-the fact destruction of the recording via, say, the application of external

magnet A magnet is a material or object that produces a magnetic field. This magnetic field is invisible but is responsible for the most notable property of a magnet: a force that pulls on other ferromagnetic materials, such as iron, steel, nickel, ...

s For many older systems that recorded at a low linear

bit density Density is a measure of the quantity of information bits that can be stored on a given physical space of a computer storage medium. There are three types of density: length (''linear density'') of track, area of the surface (''areal density''), ...

, the bit density of the recording could be determined. While Magnasee was most commonly used on magnetic media that wasn't meant to be re-used (for reading or writing), careful cleaning could remove the iron particles and allow critical media to be re-used.

References

* ''Magnetic Recording Handbook'', Marvin Camras, Springer 1988, {{ISBN, 0-442-26262-0 Magnetic devices