ASTM D5007-99(2013)
(Test Method)Standard Test Method for Wet-to-Dry Hiding Change
Standard Test Method for Wet-to-Dry Hiding Change
SIGNIFICANCE AND USE
5.1 Many architectural paints, particularly white and light tints, change significantly in film opacity as they dry. An increase in hiding is sometimes associated with porosity and poor film integrity with conventionally formulated coatings. A decrease can result in a disappointing paint job. The wet-to-dry hiding change is therefore a property of great practical importance.
5.2 This test method can be used in paint specifications and as a short, simple procedure for evaluation and quality control.
SCOPE
1.1 This test method covers the determination of the change in hiding power of an architectural coating during drying, by visual evaluation of the wet and dry film.
1.2 This test method is not recommended for colors other than white and tints.
1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.4 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)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: D5007 − 99 (Reapproved 2013)
Standard Test Method for
Wet-to-Dry Hiding Change
This standard is issued under the fixed designation D5007; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope h and h respectively.
SW SD
Since this test method is intended to measure hiding-power
1.1 Thistestmethodcoversthedeterminationofthechange
difference rather than hiding power itself, a 0.98 (98%)
in hiding power of an architectural coating during drying, by
contrast ratio standard is not required. It is necessary only that
visual evaluation of the wet and dry film.
the same standard be used for measuring both wet and dry
1.2 This test method is not recommended for colors other
films. See 3.1.8. For this purpose the standard needs to lie
than white and tints.
withinthecontrastrangeofboththewetanddrystripes,which
is true of the 0.98 (98%) contrast-ratio standard for most
1.3 The values stated in SI units are to be regarded as the
standard. The values given in parentheses are for information commercial paints. With paints of unusually low hiding, a
lower contrast standard may be required, which can be simply
only.
one of the stripes taken from a drawdown of the test paint.
1.4 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the 3.1.2 hiding power, n—the spreading rate of a paint applied
responsibility of the user of this standard to establish appro-
uniformly on a standard black and white hiding power chart to
priate safety and health practices and determine the applica- giveastandarddegreeofcontrastjustshortofcompletehiding.
bility of regulatory limitations prior to use.
3.1.2.1 Discussion—In reflectometry the standard contrast
for hiding power measurements is generally accepted as the
2. Referenced Documents
contrast ratio C =0.98 (98%), which with white and light
2.1 ASTM Standards: tinted coatings is equivalent to a visual color difference of
about0.75CIELABunits.Thatamountofcolordifferencecan
D2805Test Method for Hiding Power of Paints by Reflec-
tometry reasonably be described as “just-short-of complete-hiding.”
Sincethisisavisualmethoditemploysavisualcomparatoras
D3924Specification for Environment for Conditioning and
Testing Paint, Varnish, Lacquer, and Related Materials a standard, which is a hiding power chart with a white coating
applied at a contrast ratio of 0.98 (98%).
3. Terminology
3.1.3 logicator, n—amulti-notchapplicatorwithclearances,
3.1 Definitions of Terms Specific to This Standard:
and corresponding wet film thicknesses and spreading rates, in
3.1.1 hiding index (h ), n—the Spreading Index at a stan-
S equal percentage steps.
dard film opacity.
3.1.4 logicator scale, n—a scale with values directly related
3.1.1.1 Discussion—In this test method the latter is a visual
to the logarithms of corresponding spreading rates.
contrast standard prepared by applying a semi-opaque white
3.1.4.1 Discussion—A specified change in scale value rep-
coating on a black and white hiding-power chart to give a
resents the same percentage change in spreading rate over any
contrast ratio of 0.98 (98%) which is just short of complete
part of such a scale.
hiding, and is the conventional so-called full hiding end point
3.1.5 spreading index (h), n—the spreading rate expressed
in photometric hiding-power methods such as Test Method
in logicator scale units (LU) as described in 3.1.4 and 3.1.7.
D2805. Refer to the hiding indices of the wet and dry films as
3.1.6 spreading rate (H), n—the area covered per unit
quantity of coating.
This test method is under the jurisdiction of ASTM Committee D01 on Paint
3.1.6.1 Discussion—In this test method the quantity is
and Related Coatings, Materials, andApplications and is the direct responsibility of
Subcommittee D01.42 on Architectural Coatings.
volumetric.
Current edition approved May 15, 2013. Published May 2013. Originally
3.1.7 TG19 logicator, n—a logicator designed for this test
approved in 1989. Last previous edition approved in 2008 as D5007–99(2008).
DOI: 10.1520/D5007-99R13.
methodwitheightnotchesnumberedatfour-unitintervalsona
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
scale from 20 to 48, the notch clearances ranging from 67 to
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
264 µm (2.65 to 10.4 mils) corresponding to wet film thick-
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. nessesfrom37to145µm(1.46to5.7mils)andspreadingrates
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D5007 − 99 (2013)
2 2
TABLE 1 Equations Relating the Logicator Scale Value or
from 6.9 to 27 m /L (280 to 1100 ft /gal), with one scale unit
Spreading Index, h, to the Notch Clearance,N, Wet Film
representingachangeof5%andthefour-unitintervalbetween
Thickness, T, and Spreading Rate, H
notches a cumulative change of 21.55% in the clearance and
NOTE 1—The relationships involving T and H are based on a presumed
corresponding film thicknesses and spreading rates. Refer to
T/N ratio of 0.55, which ratio is approximate and somewhat variable,
this scale unit as a logicator unit (LU). (See Fig. 1.)
depending on coating rheology, drawdown technique, and clearance.
3.1.7.1 Discussion—The percentage difference between
4 Inch-Pound Units Metric Units
notches is calculated as (1.05 −1)×100=21.55. This per-
2 2
(mils, ft /gal): (µm, m /L):
68-h h 68-h h
centage is applicable precisely to the notch clearances and
N = 1.05 = 27.6 ÷ 1.05 N =25.4×1.05 =701÷1.05
h = 68 − 47.2 logNh = 134.3 − 47.2 log N
approximatelytotheirrelatedwet-filmthicknessesandspread-
h h
T = 0.55 N = 15.18÷ 1.05 T = 0.55 N = 385.5÷ 1.05
ing rates. The detailed relationships between scalar value and
h = 55.75 − 47.2 logTh = 122.05 − 47.2 log T
h h
the notch clearance, wet film thickness, and spreading rate are
H = 105.7 × 1.05 H =2.594×1.05
h = 47.2 log H − 95.52 h = 47.2 log H − 19.54
given in Table 1 and Table 2.
3.1.8 wet-to-dry hiding change (WDHC), n—the difference
in the Hiding Index of a paint between the wet and the dry
state, expressed in logicator units (LU) as follows:
decreasecanresultinadisappointingpaintjob.Thewet-to-dry
WDHC 5∆h 5 h 2 h (1)
S SD SW
hiding change is therefore a property of great practical impor-
3.1.8.1 Discussion—The WDHC is unchanged if the con-
tance.
trastlevelofthehidingstandardisvaried,becausetheresultant
5.2 This test method can be used in paint specifications and
changes in the two hiding power values are proportional and
as a short, simple procedure for evaluation and quality control.
their ratio therefore constant.
3.1.8.2 Discussion—TheWDHCisunaffectedbydeviations
6. Apparatus
fromtheestimatedfilmthickness/clearanceratio T/N(seeNote
6.1 TG19 Logicator —A multi-notch, varied-clearance ap-
1, Table 1), because the ratio of the two recalculated hiding-
plicatordesignedspecificallyforthistestmethod(see3.1.7and
power values is unchanged.
Fig. 1).
4. Summary of Test Method
6.2 Logicator Test Charts —Black and white hiding charts
with a chevron-stripe pattern and scale numbers printed at the
4.1 The test paint is applied with a TG19 Logicator on a
top corresponding to the paint stripes applied by the Logicator
logicator test chart (see 6.2 and Fig. 2) and the drawdown
(see Fig. 2).
examined in comparison with an agreed hiding standard
immediately after application and again after drying.
6.3 Vacuum Plate, for holding the chart flat while the
drawdown is made.
4.2 The scale numbers of the wet and dry stripes that match
the standard in contrast are recorded as the Wet Hiding Index,
6.4 Visual Hiding Standard —A narrow stripe cut from a
h , and the Dry Hiding Index h .
SW SD
logicatortestchartonwhichadurableglossywhitecoatinghad
been applied to obtain a contrast ratio of 0.98. The stripe is
4.3 Thedifferencebetweenthewetanddryhidingindicesis
mountedonablankcardforconvenienthandling,asillustrated
recorded as the wet-to-dry hiding change WDHC.
in Fig. 3.
4.4 If desired, the percent change in hiding power
...
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