ASTM D6488-08(2020)
(Terminology)Standard Terminology Relating to Print Problems
Standard Terminology Relating to Print Problems
SIGNIFICANCE AND USE
3.1 A common set of definitions is essential to improve communication and avoid misunderstanding among ink makers, substrate makers, and printers.
3.2 The term “paper” in this standard also encompasses the term “paperboard.”
3.3 Definitions that are verbatim from one of the referenced sources are indicated by giving the acronym of the organization or the author of the book at the end of the definition.
SCOPE
1.1 This terminology standard gives definitions for problems that develop with printed matter as a result of deficiencies in the ink, substrate, press, or combinations thereof.
1.2 These definitions cover the three major printing processes and are given in the following sequence: lithography, flexography, and gravure. For further information see Refs (1-4) at the end of this standard.
1.3 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
General Information
Relations
Standards Content (Sample)
This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D6488 − 08 (Reapproved 2020)
Standard Terminology Relating to
Print Problems
This standard is issued under the fixed designation D6488; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 4. Terminology
1.1 This terminology standard gives definitions for prob- 4.1 Definitions:
lems that develop with printed matter as a result of deficiencies
4.1.1 Lithographic Printing:
in the ink, substrate, press, or combinations thereof.
blistering, n—the formation of small air pockets under the
1.2 These definitions cover the three major printing pro- printed paper surface.
cesses and are given in the following sequence: lithography,
DISCUSSION—It results from moisture being trapped under the dried
flexography, and gravure. For further information see Refs ink film during heatset drying. This condition is more common with
higher ink coverage and heavier basis weight papers.
(1-4) at the end of this standard.
1.3 This international standard was developed in accor-
blocking, n—an undesired adhesion between sheets of printed
dance with internationally recognized principles on standard-
material that might occur under moderate pressure or in-
ization established in the Decision on Principles for the
creased temperature, or both, while in storage or in use.
Development of International Standards, Guides and Recom-
DISCUSSION—Damage to one or both surfaces may be visible upon
mendations issued by the World Trade Organization Technical
separation and may be due to improperly dried ink or coating.
Barriers to Trade (TBT) Committee.
bronzing, n—the metal-like reflectance which sometimes ap-
2. Referenced Documents
pears at the surface of nonmetallic colored materials.
DISCUSSION—Bronzing is perceived at the specular angle by observ-
2.1 ASTM Standards:
ing the image of a white light source, for example, and is characterized
D4361 Test Method for Apparent Tack of Printing Inks and
3 by a distinct hue of different dominant wavelengths than the hue of the
Vehicles by a Three-Roller Tackmeter (Withdrawn 2019)
color itself. The origin of the selective specular reflectance observed is
F425 Terminology Relating to Lithographic Copy Products
generally considered to be reflectance from very small particle size
(Withdrawn 2003)
pigment partially separated from surrounding vehicle at or near the ink
film surface.
3. Significance and Use
catch up, n—a condition that occurs when the non-image area
3.1 A common set of definitions is essential to improve
of the plate becomes ink receptive. See scum. [GATF]
communication and avoid misunderstanding among ink
DISCUSSION—This condition results from the insufficient feeding of
makers, substrate makers, and printers.
dampening solution.
3.2 The term “paper” in this standard also encompasses the
chalking, n—see powdering.
term “paperboard.”
3.3 Definitions that are verbatim from one of the referenced
coating pick, n—the removal of coating particles from the
sourcesareindicatedbygivingtheacronymoftheorganization
sheetsurfacethatoccurswhenthetackoftheinkexceedsthe
or the author of the book at the end of the definition.
surface strength of the substrate.
DISCUSSION—A loss in surface strength may occur during printing
when the coating is resolubilized by the fountain solution.
This terminology is under the jurisdiction of ASTM Committee D01 on Paint
and Related Coatings, Materials, andApplications and is the direct responsibility of
crocking, n—smudging or rubbing off of ink.
Subcommittee D01.56 on Printing Inks.
CurrenteditionapprovedJune1,2020.PublishedJuly2020.Originallyapproved
dot distortion, n—an undesired change in shape of halftone
in 1999. Last previous edition approved in 2013 as D6488 – 08 (2013). DOI:
10.1520/D6488-08R20. dots during plate making or printing operations, or both.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
dot doubling, n—the unintentional printing of two images
Standards volume information, refer to the standard’s Document Summary page on
slightly out of register from a single form.
the ASTM website.
DISCUSSION—Dot doublings can be the result of a mechanical
The last approved version of this historical standard is referenced on
www.astm.org. problem due to undesired movement between the plate and the blanket.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6488 − 08 (2020)
DISCUSSION—Thebasiccauseisalayoutthatistoodemandingforthe
dot gain, n—the increase in halftone dot size in relation to the
inking capacity of the particular press.
dots on the lithographic film; it is the arithmetic difference
(a) light print ghosting: a lighter image within the primary
between the dot area on the original film and dot area on the
image.Lightghostsaredefectsinaprintsolidafterothersolids
printed sheet.
(for example, large letters) strip too much ink off the form
DISCUSSION—Physical dot gain can be caused by a number of the
rollers.Thisoccurswhentheothersolidsarenexttothegripper
processing steps in prepress or during actual printing. Factors that
control dot gain on press are ink film thickness, amount of water feed, edge, between it and the defective solid.
solid print density, ink holdout/absorbance characteristics of the paper,
(b) dark print ghosting: a darker image within the primary
screen ruling, blanket release, pressure between the blanket and plate,
image. Dark ghosts result, for example, from reverse block
and pressure between the blanket and paper. Optical dot gain results
letters near the gripper edge in a defective solid because the
from light scattering in the paper.The dot gain value can be determined
reverse leaves excess ink on the form rollers; the ghosts are
using a dosimeter that calculates the apparent dot size on the print as
further away from the gripper edge than the reverse.
compared with the original dot size based on the density of the solid.
hickey, n—an imperfection caused by dirt, hardened ink, paper
dot loss, n—the total or partial loss of the smallest dots on the
debris or other unwanted particles that cling to the press or
sheets, usually in the areas of 25 % screen or less.
plate during printing.
DISCUSSION—Dot loss can be due to plate or blanket buildup caused
byanundesiredreactionbetweenthepaperandfountainsolution.(Also
DISCUSSION—Hickeys appear as either small solid printed areas
referred to as disappearing dot or vanishing dot.)
surrounded by a white halo or as unprinted spots surrounded by printed
ink.
dot slur, n—dot gain that occurs in a pronounced direction and
is not symmetrical. hickey, halo, n—a doughnut shaped hickey with an inked
DISCUSSION—Slur is caused by mechanical problems with the drive center, often caused by foreign particles such as ink skin.
and speed of the plate and blanket cylinders.
[TAPPI]
doubling, n—a printing defect in offset printing products (and
hickey, void, n—a totally un-inked spot on the printed sheet,
other indirect printing processes) that manifests itself as a
often caused by dust or pick-outs that adhere to the offset
doubled or multiple (shadow-like) contour of the image
blanket or plate, thereby interfering with transfer of ink.
elements. [KIPPHAN]
DISCUSSION—Mechanical vibration and register deviations during the ink fading, n—term used in offset printing for the variation in
printingprocesscancausedoubling.Doublingcanoccurinsingle-color
the ink density (uneven ink film) in the direction of print (as
printing but is a special danger in mulitcolor printing. As is the case
a consequence of inking unit design and content of the
with slurring, doubling results in dot grain.
printing sheet). [KIPPHAN]
embossing, n—the tendency of a paper to take a permanent
ink over-emulsification, n—a condition that occurs when a
pattern, either depressed or raised, as a result of contact with
lithographic ink picks up too much dampening solution
the blanket during printing. [TAPPI]
resulting in a weak print or snowflake pattern.
fan-out effect, n—widening of the paper web in a web-fed
ink misting, n—the ejection of fine particles of ink into the air
press, normally caused by dampening but also by printing
andontothepress,occurringwhentheinkfilmsplitsinmore
pressure, which can theoretically occur in sheet-fed printing
than one place.
as well. [KIPPHAN]
DISCUSSION—The centrifugal forces generated by high speed rollers
can cause this problem. Long inks are more susceptible to misting than
fiber pick, n—the delaminating, splitting, or tearing of paper
short inks.
surface fibers that occurs when the force between the paper
and blanket exceeds the surface strength of the paper.
ink refusal, n—the failure of a roller or plate to accept ink.
Alternative term: stripping—see Gravure Printing.
flying, n—the tendency of a printing ink or vehicle to be
DISCUSSION—The condition can be caused by gum buildup on the
ejected as large globules from a roller distribution system.
roller or plate in the image areas.
[D4361]
DISCUSSION—See also misting and spraying for comparison.
ink setoff, n—the undesirable transfer of an ink in any printing
process from fresh prints to any other surface.
ghosting, chemical, n—the appearance of gloss or dull mirror
DISCUSSION—This printing defect is caused by slow setting inks or
images that are printed on the reverse side of the sheet.
insufficient spray powder.
DISCUSSION—This phenomenon is usually caused by chemical activ-
ity of the ink during the drying phase of oxidative inks.
marking, n—the removal of printed ink from the web to idler
rolls, turn bars, or nose cone on a printing press.
ghosting, mechanical, n—the appearance of a phantom image
on the printed side of the sheet. DISCUSSION—Printing ink may then be redeposited on subsequent
printed sheets.
DISCUSSION—These images can be caused by some mechanical factor
in plate preparation, press settings or mechanical problems.
milking, n—a white colored buildup on the non-image areas of
ghosting, starvation, n—mechanical ghosting that appears in the offset blanket that usually occurs when the paper coating
solids and shadows as either a lighter image or a darker or paper filler (in the case of uncoated paper) softens due to
image than the background. inadequate water resistance.
D6488 − 08 (2020)
DISCUSSION—This condition is caused by excess hydrophilic material
misting, n—side effect of ink film splitting within an inking
such as gum.
unit, in particular on rapidly-rotating inking rollers.
[KIPPHAN]
plate wear blinding, n—the failure of the litho plate to print
DISCUSSION—Here, extremely small droplets (diameter of 10 to 50
due to erosion in the image area.
µm) of ink are released from the ink layers on the exiting nip. They
form an aerosol with the ambient air, can lead to printing defects, and
plate scumming, n—the deposit of ink on the non-image area
contribute to soiling of the press. Misting is very much dependent on
of the plate that can be in the form of minute particles or
the rheology of the ink, as well as on the velocity of the ink-carrying
larger continuous solids.
surface and the geometry of the rollers. See also spraying and flying for
comparison.
plate tinting, n—the existence of a weak coloration from the
fountain solution onto the non-image area of the plate.
moiré, n—an undesirable, unintended interference pattern
DISCUSSION—The condition occurs when pigments, with or without
caused by the out-of-register overlap of two or more regular
ink ingredients, become solubilized or emulsified into the fountain
patterns such as dots or lines.
solution.
DISCUSSION—In process color printing, screen angles are selected to
minimize this pattern. If the angles are not correct, an objectionable
plate wear, n—a physical abrading away of the non-image or
effect may be produced.
image area, or both, of the plate.
DISCUSSION—This erosion can be caused by abrasive materials in the
mottle, back trap, n—a nonuniform density variation of a
ink or on the substrate.
printed ink film due to nonuniform ink absorption into the
paper.
powdering, n—a condition where ink easily rubs off a print
DISCUSSION—This results in nonuniform transfer of the ink back onto
after the normal drying period.
the blankets of subsequent printing units of the press, which in turn is
DISCUSSION—Also referred to as “chalking.” Powdering could be due
transferred onto the following sheets (or web) of paper.
to the rapid absorption of the vehicle into the paper or the improper
pigment to binder ratio in the ink.
mottle, halftone, n—a nonuniform transfer of halftone dots.
DISCUSSION—This condition can be caused by factors such as
print void, n—a defective spot of unprinted matter in a print
irregularities in paper surface, variations in ink transfer properties or
solid or halftone that can be caused by a buildup of foreign
emulsified ink.
matter on the plate or blanket.
mottle, print, n—an uneven appearance within the continuous
railroad tracks, n—a pattern on the printed sheet extending in
ink film solid areas of a print, with respect to density, gloss
themachinedirectionthatiscomprisedofoneormorelinear
or color.
regions. [TAPPI]
DISCUSSION—Also referred to as “solid area mottle.” This effect may
DISCUSSION—This effect may be caused by excessive variations in
be caused by a varying ink film due to the uneven ink receptivity and
drying across the width of the web.
absorbency of the paper or by poorly ground ink.
mottle, trapping, n—nonuniform print due to improper tack scum, n—a condition that occurs when a lithographic plate has
sequence of the inks. become sensitized in the non-image areas and these areas
DISCUSSION—If the first down ink is lower in tack on the substrate’s
begin to take ink. [GATF]
surface, subsequent ink film(s) will not trap uniformly. In this situation,
set-off, n—the unintentional transfer of part of an image or ink
it is not uncommon for the first down color to also be pulled off the
printing substrate onto downline units causing poor density and ink from its intended location to another surface. [F425]
color contamination.
show-through, n—the printed image can be observed on the
mottle, water interference, n—nonuniform print caused by
opposite side of the sheet under normal lighting conditions.
poor ink transfer due to the printing subst
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