ASTM D5007-99(2003)

Standard Test Method for Wet-to-Dry Hiding Change

SIGNIFICANCE AND USE
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.
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.

General Information

• Status: Historical
• Publication Date: 30-Nov-2003
• ICS: 87.040 - Paints and varnishes
• Technical Committee: D01 - Paint and Related Coatings, Materials, and Applications
• Drafting Committee: D01.42 - Architectural Coatings

Relations

• Replaces: ASTM D5007-99 - Standard Test Method for Wet-to-Dry Hiding Change
• Effective Date: 01-Dec-2003
• Replaced By: ASTM D5007-99(2008) - Standard Test Method for Wet-to-Dry Hiding Change
• Effective Date: 01-Feb-2008
• Referred By: ASTM D5324-16(2022) - Standard Guide for Testing Water-Borne Architectural Coatings
• Effective Date: 01-Dec-2003

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:D5007–99(Reapproved2003)
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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope 3.1.1.1 Discussion—Since this test method is intended to
measure hiding-power difference rather than hiding power
1.1 Thistestmethodcoversthedeterminationofthechange
itself,a0.98(98%)contrastratiostandardisnotrequired.Itis
in hiding power of an architectural coating during drying, by
necessary only that the same standard be used for measuring
visual evaluation of the wet and dry film.
bothwetanddryfilms.See3.1.8.Forthispurposethestandard
1.2 This test method is not recommended for colors other
needs to lie within the contrast range of both the wet and dry
than white and tints.
stripes, which is true of the 0.98 (98%) contrast-ratio standard
1.3 The values stated in SI units are to be regarded as the
for most commercial paints. With paints of unusually low
standard. The values given in parentheses are for information
hiding, a lower contrast standard may be required, which can
only.
be simply one of the stripes taken from a drawdown of the test
1.4 This standard does not purport to address all of the
paint.
safety concerns, if any, associated with its use. It is the
3.1.2 hiding power—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
2. Referenced Documents for hiding power measurements is generally accepted as the
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
D2805 Test Method for Hiding Power of Paints by Reflec-
about0.75CIELABunits.Thatamountofcolordifferencecan
tometry
reasonably be described as “just-short-of complete-hiding.”
D3924 Specification for Standard Environment for Condi-
Sincethisisavisualmethoditemploysavisualcomparatoras
tioning and Testing Paint, Varnish, Lacquers, and Related
a standard, which is a hiding power chart with a white coating
Materials
applied at a contrast ratio of 0.98 (98%).
3. Terminology
3.1.3 logicator—a multi-notch applicator with clearances,
and corresponding wet film thicknesses and spreading rates, in
3.1 Definitions of Terms Specific to This Standard:
equal percentage steps.
3.1.1 hiding index, h —the Spreading Index at a standard
S
3.1.4 logicator scale—ascalewithvaluesdirectlyrelatedto
film opacity. In this test method the latter is a visual contrast
the logarithms of corresponding spreading rates. A specified
standard prepared by applying a semi-opaque white coating on
changeinscalevaluerepresentsthesamepercentagechangein
ablackandwhitehiding-powercharttogiveacontrastratioof
spreading rate over any part of such a scale.
0.98 (98%) which is just short of complete hiding, and is the
3.1.5 spreading index, h—the spreading rate expressed in
conventional so-called full hiding end point in photometric
logicator scale units (LU) as described in 3.1.4 and 3.1.7.
hiding-power methods such as Test Method D2805. Refer to
3.1.6 spreading rate, H—the area covered per unit quantity
the hiding indices of the wet and dry films as h and h
SW SD
of coating. (In this test method the quantity is volumetric).
respectively.
3.1.7 TG19 logicator—a logicator designed for this test
methodwitheightnotchesnumberedatfour-unitintervalsona
This test method is under the jurisdiction of ASTM Committee D01 on Paint
scale from 20 to 48, the notch clearances ranging from 67 to
and Related Coatings, Materials, andApplications and is the direct responsibility of
264 µm (2.65 to 10.4 mils) corresponding to wet film thick-
Subcommittee D01.42 on Architectural Coatings.
nessesfrom37to145µm(1.46to5.7mils)andspreadingrates
Current edition approved Dec. 1, 2003. Published December 2003. Originally
2 2
approved in 1989. Last previous edition approved in 1999 as D5007–99. from 6.9 to 27 m /L (280 to 1100 ft /gal), with one scale unit
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
representingachangeof5%andthefour-unitintervalbetween
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
notches a cumulative change of 21.55% in the clearance and
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D5007–99 (2003)
TABLE 1 Equations Relating the Logicator Scale Value or
corresponding film thicknesses and spreading rates. Refer to
Spreading Index, h, to the Notch Clearance, N, Wet Film
this scale unit as a logicator unit (LU). (See Fig. 1.)
Thickness, T, and Spreading Rate, H
3.1.7.1 Discussion—The percentage difference between
NOTE 1—The relationships involving T and H are based on a presumed
notches is calculated as (1.05 −1) 3100=21.55. This per-
T/N ratio of 0.55, which ratio is approximate and somewhat variable,
centage is applicable precisely to the notch clearances and
depending on coating rheology, drawdown technique, and clearance.
approximatelytotheirrelatedwet-filmthicknessesandspread-
Inch-Pound Units Metric Units
ing rates. The detailed relationships between scalar value and
2 2
(mils, ft /gal): (µm, m /L):
the notch clearance, wet film thickness, and spreading rate are
68-h h 68-h h
N = 1.05 = 27.6 4 1.05 N = 25.4 3 1.05 = 701 4 1.05
given in Table 1 and Table 2.
h = 68 − 47.2 logNh = 134.3 − 47.2 log N
h h
3.1.8 wet-to-dry hiding change (WDHC)—the difference in
T = 0.55 N = 15.184 1.05 T = 0.55 N = 385.54 1.05
h = 55.75 − 47.2 logTh = 122.05 − 47.2 log T
the Hiding Index of a paint between the wet and the dry state,
h h
H = 105.7 3 1.05 H = 2.594 3 1.05
expressed in logicator units (LU) as follows:
h = 47.2 log H − 95.52 h = 47.2 log H − 19.54
WDHC5Dh 5 h 2 h (1)
S SD SW
3.1.8.1 Discussion—The WDHC is unchanged if the con-
trastlevelofthehidingstandardisvaried,becausetheresultant
6. Apparatus
changes in the two hiding power values are proportional and
6.1 TG19 Logicator —A multi-notch, varied-clearance ap-
their ratio therefore constant.
plicatordesignedspecificallyforthistestmethod(see3.1.7and
3.1.8.2 Discussion—The WDHC is unaffected by devia-
Fig. 1).
tionsfromtheestimatedfilmthickness/clearanceratio T/N(see
6.2 Logicator Test Charts —Black and white hiding charts
Note 1, Table 1), because the ratio of the two recalculated
with a chevron-stripe pattern and scale numbers printed at the
hiding-power values is unchanged.
top corresponding to the paint stripes applied by the Logicator
(see Fig. 2).
4. Summary of Test Method
6.3 Vacuum Plate, for holding the chart flat while the
4.1 The test paint is applied with a TG19 Logicator on a
drawdown is made.
logicator test chart (see 6.2 and Fig. 2) and the drawdown
6.4 Visual Hiding Standard —A narrow stripe cut from a
examined in comparison with an agreed hiding standard
logicatortestchartonwhichadurableglossywhitecoatinghad
immediately after application and again after drying.
been applied to obtain a contrast ratio of 0.98. The stripe is
4.2 The scale numbers of the wet and dry stripes that match
mountedonablankcardforconvenienthandling,asillustrated
the standard in contrast are recorded as the Wet Hiding Index,
in Fig. 3.
h , and the Dry Hiding Index h .
SW SD
4.3 Thedifferencebetweenthewetanddryhidingindicesis
7. Procedure
recorded as the wet-to-dry hiding change WDHC.
7.1 Prepare a hiding standard as described in 6.4, or use the
4.4 If desired, the percent change in hiding power corre-
standard supplied with the logicator test charts.
sponding to the WDHC value is calculated and repor
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