Tack:

In printing inks, the cohesion between particles; the pulling power or separation force of ink in its transfer from a press blanket to its intended printing surface. A tacky ink has high separation forces and can cause surface picking or splitting of weak papers. A lack of tack has very little ability to transfer properly from blanket to paper because it has a low adhesion tendency, this affects trap.

Tagged Image File Format:

Computer file format used to store images from scanners and video devices. Abbreviated TIFF.

Tank Voltage:

The total between the anode and cathode of a plating bath or electrolytic cell during electrolysis. It is equal to the sum of (1.) The equilibrium reaction potential, (2.) the IR drop, and (3.) the electrode potentials.

Taper tension feature:

A means of decreasing web tension as roll diameter increases in a rewind zone; Taper tension helps produce a roll of better quality by eliminating telescoping, crushed cores, and overly tight or loose rolls.

Targa:

A file format for exchanging 24-bit color files on PCs. Abbreviated as TGA.

Target Ink Densities:

Densities of the four process inks as recommended for various printing processes and grades of paper. See also Total Area Coverage.

Tension Transducer:

A tension sensor and variation of a load cell specifically designed to measure exact web or filament tension in processing machinery.

Tension Zone:

A length of machine in which the web is under nominally the same tension, usually between driven rollers.

Thermal Oxidation:

Incineration, usually used as part of a solvent recovery system.

Thermal Transfer:

A printing process utilizing a temperature-sensitive ribbon. Through heat and pressure, the ink is selectively transferred from the ribbon to a printable surface, thus creating the desired image.

Thermography:

A printing process that produces raised type similar to engraved printing.

Thief:

An auxiliary cathode placed to divert to itself some current from portions of the work which would otherwise receive too high a current density and excess plating deposition.

Thinners:

Liquids, solvents and/or diluents, added to fountain ink for the purpose of reducing the viscosity of the ink.

Thixotropy:

A property of a liquid or plastic material that involves a reversible decrease of viscosity as the material is agitated or worked.

Three-Quarter Tones:

A neutral gray area on a reproduction scale located between the middle-tones and the shadow.

Throwing Power:

The improvement of the coating distribution over the primary current distribution on an electrode (usually cathode) in a given solution, under specified conditions. It is a measure of the uniformity of the metallic deposit on a cathode from a given plating solution.

TIFF (Tagged Image File Format):

A file format for exchanging bitmapped images (usually scans) between applications.

Tinctorial Strength:

The relative ability of a pigment or dye to impart color value to a printing ink.

Tint:

(1.) A color of very low strength or intensity, usually made by adding a small amount of colored ink or toner to a large amount of extender or opaque white. (2.) A lighter shade of ink created by printing a finer dot pattern, but using full-strength ink. A wide gamut of hundreds of shades can be created by over-printing tints of the process colors.

Tinting:

In lithography, a uniform discoloration of background caused by the bleeding or washing of the pigment in the fountain solution.

Tip In:

Usually in the book arena, adding an additional page(s) beyond the normal process (separate insertion).

TIR:

Total Indicated Runout- see runout.

Tissue Overlay:

A thin, translucent paper placed over artwork (mostly mechanical) for protection; used to indicate color breaks, position of halftones and color separations and areas on color originals that need color correction.

Titanium Dioxide:

A very opaque, white inorganic pigment.

Titration:

An analytical process for determining the quantity of an element or compound in solution by measuring the quantity of some reagent (liquid or solution) that reacts quantitatively with it.

TMP:

Thermomechanical pulp.

Tolerance:

The amount of acceptable difference between a known correct standard   (usually the customer's specifications) and a set of measured samples.

Toluene:

A commonly used solvent in publication ink systems.

Tonal Merge:

In photography, colors, textures, shapes, and details that are recorded and compressed in a shadow area which merge and record as shadows. Important details should have enough light placed upon them so they render as middle-tones and not shadows. If these details are necessary in the final reproduced image, it is highly recommended to go back and re-photograph the original, or overprint another color. See Overprinting.

Tone Compression

Reduction in the tonal range from original scene to printed reproduction.

Tone Reproduction:

The contrast of an original must adjust during color reproduction to conform to the ranges of the halftone screens from 1% to 100%. It is virtually impossible to print densities more than 100% and tones less than 2 or 3% will have no detail. This is one of the most difficult limitations of the printing process to understand or accept.

Toner:

(1.) A highly concentrated pigment and/or dye used to modify the hue or color strength of an ink. (2.) Black and colored electrostatic imaging materials used in xerographic copiers and in toner-based proofing systems.

Toning In:

See also – Running In.

Toxicity:

The ability of a substance, such as poison, to cause injury to living tissue.

Transparent Inks:

Inks that lack hiding power and permit light to pass through. They permit previous printing to show through, the two colors blending to produce a third, e.g., a transparent yellow over a blue to produce a green where the two colors are superimposed.

TR011:

See CGATS TR011/

TR012:

Under development. It will become another of a series of technical reports and standards. It is being developed by CGATS to facilitate communication among all participants in the supply chain involved in the design, preparation and printing of packaging materials. It builds upon CGATS TR 011.

Trade Shop:

Service bureau, printer or bindery working primarily for other graphic arts professionals, not for the general public.

Transformation Equations:

A set of three simultaneous equations used to transform a color specification from one set of matching stimuli to         another.

Transmission Densitometer:

Instrument used to measure the amount of light penetrating through a substrate.

Transmissive Objec:

An object that allows light to pass through from one side to the other. The color of a transmissive object results from the manipulation of wavelengths of light as they pass through.

Transparency:

An image observed or photographed by light passing through the substrate from behind.

Transparent:

Describes a material that transmits light without diffusion or scattering.  

Trap:

An overlap or underlap between colors that butt against each other to hide misregistration during printing. Type of traps include chokes and spreads.

Trapping:

The process of closing gaps between different color inks as they appear on film. Trapping is achieved by use of chokes and spreads. Wet trapping is dependent upon several press and paper conditions including hardness and holdout of the paper, tack of the inks, and general condition of the rollers, cylinders and blankets on the press. Dry trapping is printing wet ink over dry ink. Improper trapping will cause color changes.

Trees:

Branched or irregular projections formed on a cathode during electrodeposition especially at edges and other high current high-density areas.

Trichromatic:

The technical name for RGB representation of color, i.e., using red, green and blue to create all the colors in the spectrum.

Trim Marks:

Guides that show the specified cut lines on a final printed document.

Trim Size:

The final size of a printed image after the last trim is made.

Tripoli:

Friable and dust-like silica used as an abrasive.

Tristimulus Data:

The three tristimulus values that combine to define or generate a specific color, such as R 255/G 255/B 0. Tristimulus data does not completely describe a color. The illuminant must also be defined. Also, in device-dependent color models such as RGB, the capabilities of the viewer or color-rendering device must also be defined.

Tristimulus Values:

Amounts of the three matching stimuli, in a given trichromatic system, required to match the stimulus being considered.

Tritone:

An image reproduced using three colors.

TRUMATCH:

A color matching system which is based solely on color attributes attainable from CYMK printing as opposed to spot ink colors. Like PMS, an electronic version of the system is a feature of many color painting, drawing, and layout software products.

Turbulence:

Irregular flows in gases or liquids caused by physical objects in their path or by friction; a factor in gravure ink drying and solvent recovery.

Turnover:

See also - Foldover.

Twin-Wire Forming:

A method of papermaking that de-waters paper from both sides simultaneously, producing a sheet that will essentially have two wire sides rather than a wire and felt side.