ASTM D1684-96(2002)
(Practice)Standard Practice for Lighting Cotton Classing Rooms for Color Grading
Standard Practice for Lighting Cotton Classing Rooms for Color Grading
SCOPE
1.1 This practice covers practices in general use in the United States for lighting cotton classing rooms, provides general background information regarding the development and establishment of these practices, and prescribes a method of test for appraising the color quality of lamps procured for this purpose.
1.2 This standard does not purport to addressall 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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Designation:D1684–96 (Reapproved 2002)
Standard Practice for
Lighting Cotton Classing Rooms for Color Grading
This standard is issued under the fixed designation D 1684; 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 (e) indicates an editorial change since the last revision or reapproval.
INTRODUCTION
Until 1940, practically all cotton classing was done in daylight, much of it in specially skylighted
rooms designed to provide sufficient and uniform lighting on the classing tables. Cotton classification
or classing is the art and science of describing the quality of cotton according to the official standards
of the United States. Grade is divided into two categories—color grade and leaf grade. Because color
grade is an important quality factor in establishing the price and use of cotton, the color quality of
lighting is important. The cotton classer attempts to class cotton on the basis of the color the sample
and the standard would have in daylight. In classing rapidly he refers to physical standards only
occasionally each day; therefore it is most important that the lighting in a classing room shall not only
provide a constant color but that it shall make the color of cotton appear as nearly as possible as it
would in daylight so that he can take full advantage of training and memory.
In the USA, daylight at about 7500 K is what the cotton classer (1,2,3), (as well as color matchers
in other industries (4,5,6)) has found in practice to be the minimum color temperature of preferred
daylight.
1. Scope 2.2 Other Documents:
The Classification of Cotton, Agricultural Handbook Num-
1.1 This practice covers practices in general use in the
ber 566.
United States for lighting cotton classing rooms, provides
general background information regarding the development
3. Terminology
and establishment of these practices, and prescribes a test
3.1 Definitions:
method for appraising the color quality of lamps procured for
3.1.1 color grading, n—theactofidentifyingaspecimenby
this purpose.
a color grade or color score, that is specific to the color and the
1.2 This standard does not purport to address all of the
material graded.
safety concerns, if any, associated with its use. It is the
3.1.2 illumination, n—inlighting,thedensityorfluxoflight
responsibility of the user of this standard to establish appro-
on a unit area of surface.
priate safety and health practices and determine the applica-
3.1.2.1 Discussion—The lux (lx) is the SI unit of illumina-
bility of regulatory limitations prior to use.
tion and equals a luminous flux of one lumen per square metre
2. Referenced Documents of surface. The footcandle (fc) is the inch-pound unit of
illumination and equals a luminous flux of one lumen per
2.1 ASTM Standards:
3 square foot of surface. To convert footcandles to lux, multiply
D 123 Terminology Relating to Textiles
by 10.76391 (exactly).
D 1535 Practice for Specifying Color by the Munsell Sys-
tem
3.1.3 kelvin, n—the unit of thermodynamic temperature; the
SI unit of temperature for which an interval of one kelvin (K)
equals exactly an interval of one degree Celsius (1°C) and for
This practice is under the jurisdiction of ASTM Committee D13 on Textiles,
which a level of 273.15 K equals exactly 0°C.
and is the direct responsibility of Subcommittee D13.11 on Cotton and Fibers.
3.1.4 For definitions of other textile terms used in this
Current edition approved Oct 10, 1996. Published February 1997. Originally
practice, refer to Terminology D 123.
published as D 1684 – 59 T. Last previous edition D 1684 – 90.
The boldface numbers in parentheses refer to references listed at the end of this
practice.
Annual Book of ASTM Standards, Vol 07.01.
Available from Cotton Div.,Agricultural Marketing Service, U. S. Department
Annual Book of ASTM Standards, Vol 06.01.
of Agriculture, Washington, DC 20250.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D1684
4. Summary of Practice on the basis of the color the sample and the standard would
have in daylight. It is essential that the lighting in a classing
4.1 Artificial lighting is used in cotton classing rooms to
room is constant and that it makes the color of cotton appear as
simulate ideal daylight conditions in north latitudes with a
nearly as possible as it would in natural daylight.
moderately overcast sky. The quality and quantity of illumina-
5.2 Uniform lighting conditions permit classers to go from
tion, the geometry of illumination, the type of lighting unit and
one classing room to another without having to make adjust-
pattern for installation, the color of surroundings, and mainte-
ments for wide differences in the amount and quality of
nance of lighting equipment are specified in this practice.
lighting.
5. Significance and Use
6. Quality of Illumination
5.1 This practice is useful for establishing and maintaining
standard lighting conditions in cotton classing rooms. This 6.1 The standard for color quality of illumination is the
permits the classer to make a valid assessment of the color color and spectral quality of daylight of a moderately overcast
grade of cotton. The cotton classer attempts to classify cotton northern sky, as represented by the curve and data in Fig. 1 for
Wave- CIE Standard
A
length, nm for Daylight at
B
7500 K (Rela-
tive Energy)
400 101.9
10 111.9
20 112.8
30 103.1
40 121.2
450 133.0
60 132.4
70 127.3
80 126.8
90 117.8
500 116.6
10 113.7
20 108.7
30 110.4
40 106.3
550 104.9
60 100.0
70 95.6
80 94.2
90 87.0
600 87.2
10 86.1
20 83.6
30 78.7
40 78.4
650 74.8
60 74.3
70 75.4
80 71.6
90 63.9
700 65.1
A −9
nm is the abbreviation for nanometre, which is a metre 3 10 = mµ = millimicron.
B
The data for 400 to 700 nm are based on Table III of August, 1965, recommendations of the CIE colorimetry committee (E-1.3.1) for an international standard to
represent typical daylight (300 to 830 nm) of correlated color temperature 7500 K (7,8).
FIG. 1 Standard for Color Quality of Illumination for Color Grading Problems in Which the Equivalent of Light from a “Covered Sky”
is Required or Preferred. In North Latitudes this is a sky that is moderately overcast from the north.
D1684
typical daylight at 7500 K (7,8). table when units are placed end-to-end over the tables. Instal-
6.2 Tolerances for meeting this standard for color quality lation requirements should be based on the pattern of illumi-
are 6200 K correlated color temperature of color, and for nation provided by the lighting units used, calculated so that
spectral quality the spectral distribution shall be as close as the illumination will be as uniform as possible throughout the
possible to that shown in Fig. 1; in no case shall the color classing room. Units should be closed, they should be as light
renderingindexbelowerthan92,asdeterminedbytheGeneral in weight as practical, and be easy to install, inspect, and
Color Rendering Index recommended in 1965 by the Interna- maintainingoodorder.Itisrecommendedthatairconditioning
tional Commission on Illumination (CIE) described in Refer- be specified along with these lighting installations (3).
ences (9) and (10).
9.2 In classing room installations that meet the specifica-
tions of this recommendation, units about 2 by 4 ft (0.6 by 1.2
7. Quantity of Illumination
m) are widely used. They include use of spectrally neutral
diffusing glass designed not only to diffuse the light but to
7.1 Atthepresenttime,theoptimumamountofillumination
provide a very low brightness contrast. Based on the pattern of
for cotton classing is not known. For light sources that include
light provided by these units, installations in which they are
the use of fluorescent lamps, the U.S. Department of Agricul-
ture requires at the time of installation a minimum of 100 used usually are arranged as follows:
footcandles (1076 lx) on the working surface (from center to 9.2.1 Diffusing glass at the bottom of the units is set 10 ft (3
limits of classing areas). Studies (4,5,11) show that illumina-
m) from the floor and parallel to it, in rows centered 6 ft (2.1
tion above 400 fc (4300 1x) may be considered “very poor.” m) apart.
Optimum conditions lie somewhere between. Most recent
9.2.2 A minimum of four rows are recommended for an
installationsarewellabovetheminimumrequirements,usually
averagesizedroom.Increasethenumberofrowsasrequiredto
reaching a range of 150 to 200 fc (1614 to 2152 lx) on
allowefficientuseofallspacewithintheroom.Classingtables,
installation (Notes 1 and 2).
depending somewhat on their length, may be placed either
parallel to the direction of lighting or at right angles. For full
NOTE 1—The minimum range for lighting cotton classing rooms is
use of the room, lighting units should be extended to within 3
based on data in Tables X1.1 and X1.2 in Appendix X1. Many cotton
to 4 ft (1 to 1.2 m) of the side walls and as close to end walls
classingroomswerestudied;theywerelight
...
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