Colour fastness

IMPORTANCE OF TESTING
 Research and development to enable new and desirable textile
products to be produced.
 Product performance and evaluation to determine if the fabric is
suitable for the intended end use.
 Quality control to ensure that the fabric will be made properly and
efficiently. Thus claims and returns will be minimized.
 Problem analysis to determine why a fabric or textile product is not
performing as desired
 Product comparison to determine which material would be the better
value and to prevent wasteful buying.
 Proper advertising to enable ads to be truthful and not misleading or
false
 Adherence to government regulations so that the textile product can
be sold without violating any laws.

COLOUR FASTNESS &
SHADE MATCHING

COLOR FASTNESS
Property of a pigment or dye to retain its original
hue, especially without fading, running, or
changing when wetted, washed, cleaned; or stored
under normal conditions when exposed to light,
heat, or other influences.

Factors Affecting Color
Fastness
 Fiber Type
 Class of Dye Used
 Dyeing or Printing Process used
 Types of Finishing Treatments Used
 Action Of Laundering Detergents

Qualities Of The Color Evaluator
 A special individual needed who:
 Possesses a knowledge of dyes and pigments.
 Knows why color change
 Is skilled in colorfastness tests and knows their
limitations.
 Has the ability to evaluate and report color
changes.

Measured Using…
Color fastness in
• Paper: fadeometer,
• Cloth: launderometer.
Explained Further…

Types Of Colorfastness
 Adversely affected by:
 Washing
 Light
 Crocking
 Abrasion
 Gases in Atmosphere
 Frosting
 Perspiration
 Heat

GRAY SCALE
 Arrangement of Achromatic gray chips in a scale
from light to dark.
 Nine pairs of non-glossy neutral grey coloured
chips, which illustrate the perceived colour
differences.
 give a corresponding fastness rating of 5, 4-5, 4,
3-4, 3, 2-3, 2, 1-2, and 1)

Using A Gray Scale…
 Uses a class 5-4-3-2-1 rating system.
 Class 5 best, Class 1 worst.
 Half Rating, such as 3-4 also used.
 5-Excellent, 4-good, 3-fair, 2-poor, 1- very poor.
 Specimens of a given hue are matched against these gray
chips.
 They equate differences in lightness with differences in
color.

Methodology Of Testing..
 A control fabric is used, usually white or un-dyed;
also assessed for the staining which results from
contact with the test material.
 Results assessed by grading against standard
A04/A05 greyscales
 Grade of 5: no change in colour, staining
 Grade of 1: substantially different.

Methodology Of Testing
(Contd)..
 Usually only one specimen of fabric used.
 If material dyed or printed uniformly throughout
the fabric, then specimen chosen should be
representative of entire lot.
 For multi –colored printed fabric, each color
should be tested in order to evaluate every color.

Gray Scale For Staining…
 Used to evaluate a fabric’s resistance to staining.
 Normally a multi-fibre strip of 6 fibre components used for
staining test: Acetate, Cotton, Acrylic, Polyamide,
Polyester and Wool.
 Same as the other gray scale, except for the chip in each
pair that remains the same is a standard white.
 Various contrasting pair of chips are given numerical color
fastness ratings, from class 5 to class 1.
 Utilizes samples of undyed fabric to determine if a colored
fabric will stain an adjacent fabric.

Limitations Of Grey Scale
 Disagreement when bright colors are used.
 Works well with most colors otherwise.

CHROMATIC
TRANSFERENCE SCALE
 used to evaluate fabrics
resistance to crocking.
 six sets of color chips.
 Each set is graduated
from light to dark with
different rating.

Lighting Used For Evaluation
 When visually evaluating or comparing, standardized light
source should be used.
 COLOR MATCHING BOOTH frequently used for color
checking.

COLOR MATCHING BOOTH
 Contains 4 different standardized lights:
 Daylight
 Incandescent Light
 Cool White Fluorescent Light
 Ultraviolet Light
 Each used to view specimens by pushing a switch.
 Daylight used when evaluating colorfastness as color
appears closer to way usually seen.

COLORFASTNESS TO
WASHING
 Ability of the fabric to with stand the effect of laundering.
 Launder-ometer is used to evaluate colour fastness to
washing with the help of grey scales.
 The washing of fabric results in the removal of dye,
therefore staining can occur, inorder to determine the
staining, a white multifiber strip is attached to the
specimen being tested for CF to washing.
 The staining effect on each fiber in the multifiber test
fabric should be rated using the grey scale for evaluating
staining.
 It is checked afterwards for the effects of bleeding or
colour migration.
 AATCC standard detergent 124 used.

The Laundrometer
 Specimen placed in a
metal cylinder containing
water, detergent, steel
balls, and chlorine.
 Rotating action of these
cylinders produces the
same effect as textile
products being laundered.

Testing Procedure: Overview
 The specimen is placed in a metal cylinder in which water,
detergent, metal balls and chlorine are placed.
 The amount of detergent ,temperature, agitation and bleach
can be controlled.

TEST PROCEDURE
SPECIMEN PREPERATION:
Cut the specimen 2 x 6 inches, stapled with the multi fiber fabric.

PROCEDURE:
Place the sample in the container along with the steel balls and
detergent
Run the machine for 45 minute
After taking the specimen rinse it with water and soak it in acetic
solution and rinse it again with water.
Remove the excess solution
Dry the specimen and test fabric together using an hand iron
Remove the test fabric and compare it with the gray scale to find the
fastness.

COLORFASTNESS TO LIGHT
 This refers to the ability of the fabric to withstand
the sun light.
 The resistance of the sunlight depends on:
 the intensity of the light
 inherent properties of the fabric.
 Season
 altitude
 distance from the equator.

Measurement Method
 Original standard method: Sunlight method
 samples are placed in a glass cabinet and exposed to sun light from
9 am-3 pm. It is time consumable process.
 Weather-o-meter and Fade-o-meter most widely used instruments.
 Both this instruments use different light source and the temperature
and humidity are controlled with in the machine
 Specimens placed around the light source , and remain there until the
end of test.
 Then evaluated as to changes in color resulting from radiation
 Weather-o-meter is a newer and more versatile machine
 It enables specimen to be sprayed with water during the test, if desired.
 It also is able to alternate light and dark periods if continuous light
exposure is not desired.
 These conditions are used in the Weather-o-meter to test fabric for
such end uses as outdoor furniture, tents or rainwear.

Instruments and Fastness…
 Both machines have either a carbon-arc lamp or a xenon-
arc lamp as the light source.
 The degree of fastness required depends on end use.
As an example, a coat material should have more color
fastness than a colored dress shirt. Similarly clothes not
intended to worn outside should also have certain color
fastness to enable drying in sunlight.

WEATHER-O-METER

 Newer, versatile.
 It enables the specimen to be sprayed
with water if needed.
 It also manipulates the light and dark
period if continuous exposure is not
needed.
 These make it most suitable for testing
fabrics for end uses like outdoor
furniture, tenting or rainwear.

Using Weather Meter
Two testing methods are used:
 Time method
 Standard fading method

TIME METHOD
 The specimen is exposed to light for a particular
amount of time.
 After the termination of time the specimen is taken
out and evaluated.

Disadvantage
Specimen is not exposed to the same amount of light
each time the test is performed.

Test Procedure
Specimen Preparation
 Cut the specimen 2.5” x 8” with the longer dimension in lengthwise.

Test Procedure
 Mount the specimen in the cardboard holder and remove the
perforated strips so that half of the specimen area will be uncovered.
 Insert the cardboard holder into the metal holder and place in to the
machine.
 Expose the specimen for 20 hours.
 At the end of the desired exposure time period, remove the specimen
and allow it to relax in the dark at room temperature for atleast 2 hours
in order to regain moisture from the air.
 Using the grey scale for evaluating colour change, determine the
colour fastness rating for the test fabric.

COLOR FASTNESS TO
CROCKING
 The rubbing off of colors is called as crocking.
 Fabrics with large amount of surface dyes like dark color
cotton fabric tend to have poor colorfastness to crocking,
pigment dyed or printed fabrics also face the same
problem.
 Some time in order to increase the depth of the colors the
surface dyes are not washed off which also results in
crocking.

Crock Meter
 The crock meter is used to find the
color fastness to crocking.
 This instrument has a finger covered by
a white cotton fabric which would rub
against the specimen.
 This test should be performed both as
wet and dry test.
 The wet test is an severe test since
moisture helps in removal of dyes

COLOR FASTNESS TO CROCKING
Procedure
Specimen Preparation
 Cut two specimens on the bias, 8”x8” and place the test
specimen on the crock meter so it will be rubbed in the
bias direction.
 Test Procedure
 Mount a dry, white crock test cloth over the finger section of the crock
meter so that it will be rubbed in the bias direction.
 Lower the covered finger, causing the crock test cloth to slide over the
coloured specimen for 10 complete cycles.
 Remove the specimen and the white crock test cloth.
 Perform a wet crocking test by the same procedure.
 Rate the crock test cloths using the colour transference chart.

COLOR FASTNESS TO
PERSPIRATION.

 Perspiration can cause a fabric to
change color as well as resulting in
staining of adjacent material.
 The test is attempted to stimulate the
actual condition. the specimen is
heated for 6 hours at 38°C .
 A multifibre test fabric is placed
against the specimen, the test is
carried out and later evaluated for
bleeding or color migration.
 After the test is completed ,the
specimen is evaluated using the gray
scale and the average rating is
reported.

TEST PROCEDURE
 Cut the specimen of 2 ¼” x 2 ¼”
 Cut the multifiber fabric to 2 x 2 inch

PROCEDURE:
 Immerse the test sample and the specimen in the acid solution for 15
min.
 With draw the fabric and remove any excess liquor
 Place the specimen in the perspiration tester
 Load the tester with 10 pounds of pressure.
 Place the loaded tester in an oven and heat it to 100*f for 6 hours
 Remove the tester from oven and allow the fabric to dry at room
temperature.
 Remove specimen and test cloth and Compare with gray scale.

COLOR FASTNESS TO FROSTING

 Frosting is the change of color caused by a localized ,
flat abrasive action.
 Fabrics that have poor dye penetration possess poor
colorfastness to frosting.
 Fabric that are cross dyed also possess poor color
fastness (due to differences in the abrasion resistance)
.

Difference Between Crocking Test and
Frosting Test
 Crocking evaluates the appearance of the specimen
 Frosting only evaluates the rubbing cloth, not the
specimen.

COLOR FASTNESS TO GASES IN
ATMOSPHERE
 The dyes in the textile material are affected to a various degree by
atmospheric gases.
 The major cause for this is due to the reaction of disperse dye with ozone
and oxides of nitrogen.
 The disperse dyed with acetate fabric has the maximum effect while
nylon, polyester, acrylic has low effect.
 Inhibitors are used for this purpose but are not permanent.
 Darker, brighter change more dramatically.
 Typical changes: Blues turning pinkish, browns turning reddish, greens
turning brownish.

Instruments Used

 GAS FADING CHAMBER:-tests the effects of
oxides of nitrogen.
 OZONITER (ozone exposure chamber):-tests the
effect of ozone.

General Procedure
 The specimens are placed in the gas filled chamber for a particular
time along with the control fabric.
 The tests are conducted at 140*F for approximately 2-3 hours.
 The relative humidity is normally kept low due to the heating of gases.
 Gas fading termination: when blue sample turns a specific purple
color.
 Ozone fading test: gray sample turns a standard brown color

TEST PROCEDURE

 Cut the specimen 2 x 4 inches ,with the long direction length wise
 Cut the blue acetate control swatch 2 x 2 inches long

TEST PROCEDURE:
 Place the specimen(2x4inches)and control sample(2x2inches)in the gas
fading chamber.
 Heat the chamber to about 140*f by using Bunsen burner.
 Leave the specimens in the chamber until the color changes from blue
to purple.
 Change the control sample and repeat the procedure (only for ozoniter
test, sample changes from grey sample turns brown.
 Using The Gray Scale Determine The Color Fastness Rating.

TEST PROCEDURE
Cut two circular specimen of 4 ½ inches (emery method)
Cut two circular specimen of 5 inches (screen wire method)

PROCEDURE(EMERY METHOD):
 Place the emery paper and the specimen on the tester
 The pressure on the diaphragm is set to be 3 psi and place a 3 pound load
on the head.
 Start the tester and allow it to run for 100 continuous cycles.
 Remove the specimen and vaccum it n order to remove fibre and abradant
residue.
 Hand rinse the specimen by bolting it between two white cotton fabric hand
iron at 300*f.
 Repeat the procedure for other specimen, using gray scale find the color
fastness.

COLOR FASTNESS DUE TO HOT
IRON
 The change in color of the garment due to hot iron and dry
heat can be found by Contact Heat Tester.

CONTACT HEAT TESTER
 The heat contact tester consist of 3
pairs of individually controlled heaters
 allows simultaneous testing of 3
differing temperatures in the range
100°C to 230°C.
 After the allocated time the specimens
are taken out and is compared to the
gray scale from which the color
fastness is found out

COLOR FASTNESS TO WATER
SAMPLE PREPERATION:
Cut the specimen and the multi fiber specimen of 6 x 6 cm and sew it
together.

PROCEDURE:
 Place the specimen in a Petri dish and add distilled water to a depth of
1.5 cm
 Soak the specimen at room temperature for 15 min with occasional
agitation
 After removing the excess water place the specimen in perspir-o-meter
with a load of 10 pounds.
 Place the total unit in the oven at an temperature of 38*c for 18 hours
 Remove he specimen from the oven and dry it at standard atmosphere.
 Compare the sample with the gray scale to find the fastness.

What Makes One Perceive Color
?
 Light falls on the object and is partially absorbed.
 The light that is not absorbed is reflected and falls on the color receptors in
the eye.
 The receptors convert the incident light into stimuli, which are then
conducted via nerves to the brain.
 Here the stimuli are interpreted and a color perception is formed

How are colors defined ?
Three numerical values:
 Hue
The actual color of the sample.
 Similarity of one or a mixture of one or more colors out of the primary
ones.
 Value
 Property that arises out of the fraction of incident light being reflected
from the sample.
 Saturation Of Color
 Chroma
 View at a given illuminance level.
 Brightness of the Sample

 Form the basis of colourimetry.
 Human eye can perceive light wavelength of 350 to 750 nm .

VALUE
10P(89)
10RP(01)
10PB(75)
10R(11)

10YR(19)

HUE10B(65) CROMA

10Y(31)
10BG(57)

10G(49) 10GY(41)

Color order system
 Any systematic rational method of arranging all
possible colors or subsets by means of material
samples selected so that they represent all object
color.

NEED FOR COLOR ORDER
SYSTEM
 Human Inability to distinguish between tens of
millions of shades perceived.

Merits of color order system

 Realistic, easy to understand.
 Standard viewing conditions.
 No instrument required.
 Calibrated in terms of tristimulus values.
 Visually uniform color spaces, such as Munsell and OSA can
prove a useful way of organizing the colors of a digitally
controlled color television monitor.

Demerits of color order system
 Not easily convertible amongst the wide varieties available.
 Difference between the intended aim color and actual color of the
physical samples quite high for an atlas.
 It is not possible to include all perceivable colors in any color order
system.
 The appearance of larger samples of identical color notably different.
 Difficult to compare samples with color standards of different texture
and material.

Type of color order system
 Munsell color order system
 OSA color order system
 Chroma cosmos
 CIE colorimetric system
 RAL system
 Practical color coordinate system
 OSA-UCS system etc.

COLOR MATCHING
 Color matching can be done in two ways:
 Visual color matching under illuminant.
 Computerized color matching system (Spectro
photometer)

Process Of Color Matching
 Basic information needed:
 light source
 fabric quality
 Specific requirements (process flow)

Visual color matching
 Shade matching is done under light box in a darkroom.
 Both standard and sample are placed under same illuminant and
matched visually.
 A trial and error method.

Light Viewing Cabinets
By Gretag Macbeth

Different Light sources
 Illuminants
standard light sources defined by specific spectral power
distribution(SPD). These may be:
 Natural day light
 Tungsten lamp
 Tungsten-Halogen Lamp
 Carbon arc lamp
 Mercury and sodium vapor lamps
 Xenon arc lamps
 Fluorescent tubes
 Lasers
 UV lamps
 Cool white

Lab Facilities for Color
Matching
Spectrophotometer

Process for color matching in
Spectrophotometer
 Standard shade fed to the spectrophotometer by measuring
its reflectance value.
 difference of the reflectance value(DE) obtained.
 DE should be as close as possible to standard shade.

Wavelength (nm)

Reflectance (%)

wavelength

DE Measurement
 Two methods present:
1)Lab method, DE= sqrt[(dl/l)^2+(da/a)^2+(db/b)^2]
2)Lch method, DE= sqrt[(dl/l)^2+(dh/h)^2+(dc/c)^2]
dL=Value
da=red or green values (RGB Value)
db=yellow or blue relative values
dc=Chroma
dh= Hue

Color development by CCM

 Based on the reflectance value computer will calculate some recipes of
different dye stuff which may ultimately produce the desired colour
 Colour matching is a trial and error method. The shade which was
produced by computer prediction may not match under particular light
source which are checking visually in the light cabinet.
 If the shade doesn’t match with the standard then a second attempt is
taken with the help of CCM or by visual analysis.

Read X,Y,Z of std & data for dyes & substrate

Select a new combination of 3 dyes

Calculate C1,C2,C3 For 3 dyes

YES Negative conc. Or outside tolerance? NO

Calculate reflectance & XYZ value for formula Calculate new Conc.
from ΔXYZ

YES Compare XYZ values close enough?
NO

Calculate colour difference under different
illuminants (metamerism) & cost

YES
NO All possible combinations covered?

OUTPUT

Metamarism
 A colored object appears to be one colour under a given light source such as
daylight, but appears to change colour under another light source
 five types:
 Illuminant
 Observer
 Geometrical
 Field-size metamerism
 instrumental metamerism

Methods for Shade Development
 Cold Pad Batch (Silicate/Soda Ash/Mixed Alkali)
 Pad Dry Chemical Pad Steam (Reactive & Vat Dyes)
 Pad Steam (Reactive Dyes)
 Wet on Wet (Reactive & Vat Dyes)
 Pad Dry Cure (Caledon Dyes)
 Pad Thermosol (Reactive ECONTROL & PES/CO Blends)

Discussion…
For each of the following garment, give 3 color
fastness tests which would determine if the
indicated dyed fabric is suitable for the end use:
• 100% nylon bathing suit
• 100% acetate summer daytime dress
• 100% wool winter coat
• 100% acrylic winter sweater

Discussion…
Which Rating is better for colorfastness to light for a
woman’s summer dress:
Class 5- 20 hours
Or
Class 4- 40 hours?

Colour fastness

Colour fastness

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