ASTM D344-97(2004)
(Test Method)Standard Test Method for Relative Hiding Power of Paints by the Visual Evaluation of Brushouts
Standard Test Method for Relative Hiding Power of Paints by the Visual Evaluation of Brushouts
SIGNIFICANCE AND USE
This test method evaluates the hiding power of a test paint relative to a comparison paint. The results have significance only within that relationship. It may be used for production control or quality comparisons.
When a paint is applied by brush or any other practical method, the opacity of the film is affected by variations in film thickness related to the application procedure and to the application characteristics of the paint. Two paints that hide equally well by this method might therefore differ considerably when applied with a doctor blade, since the latter method gives essentially perfect leveling. Different brushes or surface application conditions can likewise give different results.
Note 1—Test Method D 2805 describes an instrumental method for quantitatively determining hiding power without reference to a material paint standard. The paint film is applied at a uniform thickness (for example, with a doctor blade), the film thickness is measured rigorously, and the opacity is evaluated photometrically. Hiding power is thereby determined with a high degree of precision.
Test Method D 344 is less precise than Test Method D 2805, but is more practical because it is responsive to the application characteristics of paints, and is simpler in concept and execution.
SCOPE
1.1 This test method provides for the qualitative and quantitative visual determination of the hiding power of a test paint relative to that of a comparison paint.
1.2 This test method describes only a brushout application procedure in specific detail, but its concepts are valid for other methods of application as well.
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
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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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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:D344–97(Reapproved2004)
Standard Test Method for
Relative Hiding Power of Paints by the Visual Evaluation of
Brushouts
This standard is issued under the fixed designation D344; 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 Spectrophotometry Using Bidirectional (45°:0° or 0°:45°)
Geometry
1.1 This test method provides for the qualitative and quan-
titative visual determination of the hiding power of a test paint
3. Terminology
relative to that of a comparison paint.
3.1 Definitions:
1.2 This test method describes only a brushout application
3.1.1 For definitions of terms used in this test method, refer
procedure in specific detail, but its concepts are valid for other
to Terminology D16 and the Paint/Coatings Dictionary.
methods of application as well.
3.2 Definitions of Terms Specific to This Standard:
1.3 The values stated in SI units are to be regarded as the
3.2.1 relative hiding power, qualitative—the characteriza-
standard. The values given in parentheses are for information
tion of a test paint as being better, equal, or poorer in hiding
only.
power than a comparison paint.
1.4 This standard does not purport to address all of the
3.2.2 relative hiding power, quantitative—thespreadingrate
safety concerns, if any, associated with its use. It is the
of a paint expressed as a percent of the spreading rate of a
responsibility of the user of this standard to establish appro-
comparison paint at equal hiding.
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use.
4. Summary of Test Method
2. Referenced Documents 4.1 Qualitative—The test and comparison paints are
2 brushed out uniformly at the same spreading rate on black and
2.1 ASTM Standards:
white hiding power charts. After drying the brushouts are
D16 Terminology for Paint, Related Coatings, Materials,
compared visually to see which paint has been most effective
and Applications
in reducing the substrate contrast.
D1475 Test Method For Density of Liquid Coatings, Inks,
4.2 Quantitative—Additional brushouts are made with the
and Related Products
comparison paint, if and as necessary, to determine the spread-
D1729 Practice for Visual Appraisal of Colors and Color
ing rate at which it matches the hiding of the test paint
Differences of Diffusely-Illuminated Opaque Materials
brushout.
D2805 Test Method for Hiding Power of Paints by Reflec-
tometry
5. Significance and Use
D5068 Practice for Preparation of Paint Brushes for Evalu-
5.1 This test method evaluates the hiding power of a test
ation
paint relative to a comparison paint. The results have signifi-
E1247 Practice for Detecting Fluorescence in Object-Color
cance only within that relationship. It may be used for
Specimens by Spectrophotometry
production control or quality comparisons.
E1347 Test Method for Color and Color-Difference Mea-
5.2 When a paint is applied by brush or any other practical
surement by Tristimulus Colorimetry
method, the opacity of the film is affected by variations in film
E1349 Test Method for Reflectance Factor and Color by
thickness related to the application procedure and to the
application characteristics of the paint. Two paints that hide
equallywellbythismethodmightthereforedifferconsiderably
This test method is under the jurisdiction of ASTM Committee D01 on Paint
when applied with a doctor blade, since the latter method gives
and Related Coatings, Materials, andApplications and is the direct responsibility of
essentially perfect leveling. Different brushes or surface appli-
Subcommittee D01.26 on Optical Properties.
Current edition approved Nov. 1, 2004. Published November 2004. Originally cation conditions can likewise give different results.
approved in 1932. Last previous edition approved in 1997 as D344 – 97. DOI:
NOTE 1—Test Method D2805 describes an instrumental method for
10.1520/D0344-97R04.
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
Standards volume information, refer to the standard’s Document Summary page on Published by Federation of Societies for Coatings Technology (FSCT), 492
the ASTM website. Norristown Rd., Blue Bell, PA 19422-2350, http://www.coatingstech.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D344–97 (2004)
quantitatively determining hiding power without reference to a material
7.3 Calculate to three significant figures the volume V in
paint standard. The paint film is applied at a uniform thickness (for
millilitres to apply for the selected spreading rate SR as
example, with a doctor blade), the film thickness is measured rigorously,
follows:
and the opacity is evaluated photometrically. Hiding power is thereby
100 4074.6
determined with a high degree of precision.
V~mL! 5 5 (1)
2 2
SR m /L! SR~ft /gal!
~
5.3 Test Method D344 is less precise than Test Method
D2805, but is more practical because it is responsive to the
7.4 Calculate to three significant figures, the weight W in
application characteristics of paints, and is simpler in concept
grams corresponding to the volume V (mL) as follows:
and execution.
W~g! 5 V~mL! 3 D~g/mL!
6. Apparatus
6.1 Balance,top-loadinglaboratorybalancehavingacapac-
7.5 To prepare a brushout, first stir the paint well. Then
ity of 100 g and sensitivity of 0.1 g.
precondition the brush by dipping it into the paint and working
6.2 Syringe, 10-mL capacity.
it out on a smooth, nonporous surface as described in Practice
6.3 Paint Brush, ferrule 50 mm (2 in.) wide and 14 mm ( ⁄16
D5068. Take up the desired volume of paint in the syringe and
in.) thick, tapered polyester filaments 70 mm (2 ⁄4 in.) long
weigh it with the brush in the empty container. Place the test
with flagged chisel trim tip.
chart on a level bench top, distribute the paint evenly over the
6.4 Container, ⁄2-pint can or 250-mL beaker.
test area of the chart, then brush the paint out uniformly within
6.5 Test Surface, a smooth-surfaced paper chart having
the test area. Set the brushout aside to dry in a horizontal
adjacent black and white areas and coated with a suitable
position, protected adequately from dust and under normal
varnish or lacquer so as to render the surface impervious to
room conditions of ventilation and temperature. Reweigh the
paint liquids. The black and white areas of the chart shall have
empty syringe with the brush and container.The loss of weight
luminous reflectance factors of 1 % maximum and 75 %
represents the actual weight of paint applied to the test surface
minimum, respectively, when tested in accordance with Test
as opposed to the intended weight calculated from 7.3 and 7.4.
Methods E1347 or E1349. The white areas of the charts used
If there is a discrepancy do not attempt to correct it by
in any one testing program shall not differ in their reflectance
removing or applying paint since this would disturb the
factors by more than 1 %, and shall be nonfluorescent. Any
leveling of the brushout. Instead, calculate the actual spreading
suitable regular design of contrasting areas may be used. The
rate as follows:
chart shall have a defined test area of 0.1 m . Larger test areas
B
may be used if available, with appropriate modification of the
SR 5 3 SR (2)
A B
A
indicated calculations.
6.6 Illumination, a light source providing diffuse light of
reasonable intensity, preferably northern sky light or an ap- where:
SR = actual spreading rate,
proximation of same. (See Practice D1729).
A
B = intended weight,
7. Preparation of Brushouts
A = actual weight, and
SR = intended spreading rate.
7.1 Select a convenient and suitable spreading rate, mutu- B
ally agreeable to all parties involved in the testing program,
8. Evaluation Procedure
and preferably in the range from 9.8 to 19.6 m /L (400 to 800
ft /gal). In any case, the spreading rate shall not be so low that
8.1 Viewing conditions—When the test and comparison
the substrate contrast is difficult to see, nor so high that it
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