ASTM D7298-06(2011)e1
(Test Method)Standard Test Method for Measurement of Comparative Legibility by Means of Polarizing Filter Instrumentation
Standard Test Method for Measurement of Comparative Legibility by Means of Polarizing Filter Instrumentation
SIGNIFICANCE AND USE
This test method assists in evaluating the effect of layout, typeface, type size, color, and background on the legibility of printed matter.
Previous research has shown that results are more significantly impacted by subject age than any other effect. Older subjects tend to require more light when using this instrument. Because subjects age at different rates as a result of lifestyle and genetics, variability of data tends to increase with increasing age. This test method was developed using subjects of ages 19 to 28 years. It is advised that subjects age 19 to 28 be used in cases where variability needs to be kept to a minimum.
Testers can compare legibility between various groups of subjects (by age, light intensity, distance, vision characteristics of the subjects) and one against other label configurations within groups of subjects
SCOPE
1.1 This test method provides an objective means to comparatively measure the ease of reading printed matter for use in package labeling.
1.2 This test method is not intended to quantify the legibility of a printed item against a standard but to compare its legibility against other items.
1.3 This test method uses human subjects to view printed matter mounted in a specialized instrument.
1.4 The user of this test method must be aware that results may differ from one age group of subjects to another.
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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Standards Content (Sample)
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Designation: D7298 − 06 (Reapproved 2011)
Standard Test Method for
Measurement of Comparative Legibility by Means of
Polarizing Filter Instrumentation
This standard is issued under the fixed designation D7298; 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.
ε NOTE—Minor editorial corrections were made to Sections 3.2.5, 3.2.6, and 7.3 in April 2011.
1. Scope 3.2.2 analyzer—a moveable polarizing filter; the subject
operatesahandwheeltorotatetheanalyzer(seeFig.1andFig.
1.1 This test method provides an objective means to com-
2).
paratively measure the ease of reading printed matter for use in
package labeling. 3.2.3 degrees of rotation—the angle of rotation of the
analyzer where 0 is equivalent to no light transmission and 90
1.2 Thistestmethodisnotintendedtoquantifythelegibility
is equivalent to full light transmission.
ofaprinteditemagainstastandardbuttocompareitslegibility
3.2.3.1 Discussion—At 0° rotation, the analyzer and polar-
against other items.
izer optical axes are perpendicular to one another.
1.3 This test method uses human subjects to view printed
3.2.4 easel—located on top of the moveable stage; it is a
matter mounted in a specialized instrument.
platform where printed matter is placed to be read (see Fig. 1
1.4 The user of this test method must be aware that results
and Fig. 2).
may differ from one age group of subjects to another.
3.2.5 hand crank—a crank located at the front of the
1.5 This standard does not purport to address all of the
instrument that adjusts the distance of printed matter by
safety concerns, if any, associated with its use. It is the
moving the stage and easel. When it is rotated clockwise, it
responsibility of the user of this standard to establish appro-
moves the moveable stage closer to the subject, and when it is
priate safety and health practices and determine the applica-
rotated counterclockwise it moves the stage away from the
bility of regulatory limitations prior to use.
subject (see Fig. 1 and Fig. 2).
3.2.6 hand wheel—a wheel subjects turn to rotate the
2. Referenced Documents
analyzer. Counterclockwise rotation increases the light trans-
2.1 ASTM Standards: mitted and raises the legibility index. Clockwise rotation
D996 Terminology of Packaging and Distribution Environ-
decreases the light transmitted (see Fig. 1 and Fig. 2) and
ments lowers the legibility index.
3.2.7 legibility—the ease of deciphering or reading printed
3. Terminology
matter, as measured by the legibility index in this test method.
3.1 Definitions—Terms and definitions used in this test
3.2.8 legibility index—the name given to the degrees of
method may be found in Terminology D996.
rotation of the analyzer, the reporting unit for the measurement
of legibility. The first point where the printed matter becomes
3.2 Definitions of Terms Specific to This Standard:
easy forthe subject to read.
3.2.1 age group—subjectsaregroupedbyagesinaspecified
range.
3.2.9 moveable stage—a device topped with an easel that is
mounted on a track within the legibility instrument that adjusts
the distance between the subject and the easel.
This test method is under the jurisdiction ofASTM Committee F02 on Flexible
3.2.10 polarizer—a fixed polarizing filter, mounted in the
Barrier Packaging and is the direct responsibility of Subcommittee F02.50 on
instrument (see Fig. 1 and Fig. 2).
Package Design and Development.
Current edition approved April 1, 2011. Published April 2011. Originally
3.2.11 subject—the person viewing the printed matter in the
approved in 2006. Last previous edition approved in 2006 as D7298 – 06. DOI:
instrument and controlling the rotation of the analyzer.
10.1520/D7298-06R11E01.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
3.2.12 tester—the person conducting the experiment.
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
3.2.13 training reference—Astandardmessagecreatedinan
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. 8 point font. Subjects view the training reference before data
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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D7298 − 06 (2011)
NOTE 1—*Analyzer and polarizer are actually just inside the front wall of the instrument; subject looks through them using a shielded eyepiece (See
photo in Fig. 2). They are shown in the schematic to give researchers a clear idea of the instrument’s construction.
FIG. 1 Schematic of the Legibility Instrument
FIG. 2 Photo of Legibility Instrument
collection begins so that they become accustomed to the
instrument without affectingtest results.
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D7298 − 06 (2011)
4. Summary of Test Method rheostat. The instrument should be constructed so that the
angle of the light source relative to the easel does not produce
4.1 This test method describes a means for evaluating the
glare.
legibility of printed matter such as package labeling, printed
6.5.4 The instrument shall have a light sensor, which
inserts, and carton graphics by defining a standard procedure
measures the illumination incident on the easel.
for measuring the comparative legibility of printed matter
6.5.5 The instrument shall have an eye shield to position the
under consistent, controlled light conditions by the use of a
test subject’s eyes and shield the filters from ambient light.
specialized instrument.
6.5.6 The instrument is not capable of accommodating the
height of the subject. Chair height shall be adjustable by the
5. Significance and Use
subject.
5.1 This test method assists in evaluating the effect of
layout, typeface, type size, color, and background on the
7. Equipment Controls and Monitors
legibility of printed matter.
7.1 Analyzer rotation control (hand wheel), capable of
5.2 Previous research has shown that results are more
rotating the analyzer through a full 90°, from total light
significantly impacted by subject age than any other effect.
blockage to full transmission.
Older subjects tend to require more light when using this
7.2 Analyzer rotation measurement (readout of legibility
instrument. Because subjects age at different rates as a result of
index), having a sensitivity of 0.1°.
lifestyle and genetics, variability of data tends to increase with
increasing age. This test method was developed using subjects
7.3 Rheostat, capable of providing variable light levels.
of ages 19 to 28 years. It is advised that subjects age 19 to 28
7.4 Built-in light sensor (readout of light level), a digital
be used in cases where variability needs to be kept to a
readout instrument capable of measuring light levels to 0.1 fc.
minimum.
7.5 Stage distance, measurable to an accuracy of 61cm
5.3 Testers can compare legibility between various groups
(0.4 in.).
of subjects (by age, light intensity, distance, vision character-
isticsofthesubjects)andoneagainstotherlabelconfigurations
8. Procedure
within groups of subjects
8.1 Using the hand crank, the tester adjusts the moveable
stage so that the distance from the easel to the subject’s eyes
6. Apparatus
falls between 16 in. (41 cm) and 20 in. (51 cm).
6.1 The legibility instrument (see Fig. 1 and Fig. 2)isa
8.2 The tester shall measure and record the visual acuity of
rectangular structure designed to minimize light leakage and to
the subject, using a near distance visual acuity card with the
provide an internal platform to hold printed matter to be tested.
Snellen visual acuity scale.
6.2 The interior shall have a gray or black matte surface to
8.3 The tester shall record the subject’s gender and age
minimize internal lig
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