Textile Information

2009-04-16T09:14:00.000-07:00

Preparation Of Printing Pastes
Type of specific formulation used depends on the fiber, the colorant
system used and, to some extent, the type of printing machine.
TvDicaZ Inmedients Used Include:

Dyes or pigments

Thickeners

Binders, cross-linking agents

Sequestrants

Dispersing agents - surfactants

Water-retaining agents (humectants)

Adhesion promoters

Defoamers

Catalysts

Hand modifiers

2009-04-16T09:02:00.000-07:00

Types Of Printing Processes

Automatic Flat Screen Printing

A Approximately 17% of printed goods

B. Advantages

1. Largerepeats

2. Multiple strokes for pile fabrics

C. Disadvantages

1. Slow

2. No continuous patterns

Rotarv Screen Printing

A. Approximately 50% of printed goods

B. Advantages

1. Fast

2. Quick changeover of patterns

3. Continuous patterns

C. Disadvantages

1. Design limitations

2. Small repeats

Engraved Roller Printing

A Approximately 26% of printed goods

B. Advantages

1. High design capability

a. Finedetail

b. Multiple tones

C. Disadvantages

1. Copper cylinders very expensive

2. Not economical for short runs

3. Requires highly skilled workers

Heat Transfer Printing

A. Approximately 7% of printed goods

B. Advantages

1. High quality prints

2. Fewer seconds

3. Economical for short runs

4. Practically pollution free

C. Disadvantages

1. Slow

2. Primarily only for polyester

Case Studies for Textile Printing (11)

2009-04-15T08:01:00.002-07:00

CASE STUDIES FOR TEXTILE PRINTING
CASE NO. 11
Description: Kemp Furniture used several process
modifications to reduce their overall waste volume. As
a furniture manufacturer, the traditionally used solventbased
inks to print wood grain on plywood and fiberboard.
Courses of Action:
With only minor changes in operating procedures, the
company substituted water-based inks for the solvent-based
inks.
Savings :
The net result of this initial change was to reduce
solvent waste by 30 - 40%. These waste solvents were
reused, where possible, to clean pumps and piping. This
was all accomplished with no major capital outlay. Offsite
recovery of solvent was used and this solvent reused
in processing.

Case Studies for Textile Printing

2009-04-15T08:01:00.001-07:00

CASE STUDIES FOR TEXTILE PRINTING
CASE NO. 10
Description: Ellen Knitting Mills, a North Carolina
hosiery company, was discharging spent dye bath water to
a municipal sewer system. The water temperature of 130° F.
caused many problems for the sewer treatment system.
Courses of Action:
The company decided to purchase a heat reclaimation
system. This type system is generally only cost effective
if there is a sufficient flow of water at a high enough
temperature. The net result of this action was reduced
thermal pollution, reduced waste treatment costs and
recovery and reuse of energy.
Savings:
The company invested $100,000 in a heat recovery and
exhange system reducing the effluent temperature from 130°F
to 70°F. This removed heat was used to preheat incoming
feed water for dye tubs from 55°F. to 105°F. This
preheating operation alone saved approximately 52,000
gallons of fuel oil per year. Total payback for the system
was two years.

Case Studies for Textile Printing

2009-04-15T07:59:00.000-07:00

CASE STUDIES FOR TEXTILE PRINTING
CASE NO. 9
Description: United Piece Dye Works is a textile dyeing
and finishing operation located in North Carolina. The
company because of its processing operations had a
problem with phosphorous containing materials in its
effluent.
Courses of Action:
The company was able to meet stringent discharge limits
on phosphorous by making chemical substitutions in their
production processes. Initially, a detailed chemical
analysis and evaluation of their processing was performed
to identify sources of phosphorous. Where possible, nonphosphorous
or non-phosphate containing chemicals were
substituted.
Savings:
Through this substitution, the use of hexametaphosphate
was reduced and the use of phosphoric acid was totally
eliminated. The level of phosphorous in the company's
effluent was reduced from 7.7 mg/liter to less than 1
mg/liter. United Piece Dye Works was able to meet these
effluent limits without any capital expenditure for
phosphorous removal or quality reduction in their products.

Case Studies for Textile Printing (8)

2009-04-15T07:56:00.001-07:00

CASE STUDIES FOR TEXTILE PRINTING
CASE NO. 8
Description: RJR Archer, Inc. is a paper printing
operation. The company was having a great deal of
problems with air emissions from its printing presses.
Courses of Action:
RJR Archer installed a carbon adsorption system to
capture and recover 98% of the solvents lost to the
atmosphere from drying ovens. This amounted to an average
of 2,655 gallons per day. This solvent could be either
reused or sold. By properly recirculating air exhaust from
its drying ovens before distillation, the size of the
system was smaller than originally predicted.
Additionally, all inks formulations were reviewed and
reformulated using a maximum of two solvents per blend,
therefore increasing the recovery system efficiency.
Savings:
RJR Archer saves over $6,300 per day in solvent costs.
The payback for the $4.3 million recovery system was 2.5
years. After payback, RJR Archers estimated an annual
$1.7 million net cost savings.
Air emissions are also very important to a number of
textile printers.

Case Studies for Textile Printing (7)

2009-04-15T07:55:00.001-07:00

CASE STUDIES FOR TEXTILE PRINTING
CASE NO. 7
Description: Rexham Corp. prints product labels using
alcohol/acetate based formulations using flexographic
printing techniques.
Courses of Action:
The company was able to reduce its waste generation
through process modification. Rexham substituted water
based inks for the traditional solvent based materials.
The net result was to reduce the quantity of solvent waste
generated and the quantity of solvent released to the
atmosphere. However, gloss finish labels could not be
printed this way. There was also a net decrease in
printing speed using the water-based inks.
Savings:
This modification did not require Rexham to incur
any large capital costs; however, some operator retraining
was required. Because the company also purchased an onsite
distillation system for solvent recovery for $16,000,
Rexham Corp. saves $15,000 per year in virgin solvent costs
and $22,800 per year in waste disposal costs. Total payback
for the process modifications and solvent recovery
systems was 5 months.
As can be seen, this example relates directly to many
textile printing operations.

Case Studeis for Textile Printing (6)

2009-04-15T07:54:00.001-07:00

CASE STUDIES FOR TEXTILE PRINTING
CASE NO. 6
Description: American Enka Co. (now BASF) produces nylon
yarn. Isopropyl alcohol was used as a solvent for a
fatty amine. Previously the company employed an outside
firm for the distillation and reuse of solvent. Average
solvent losses were 15% with some as high as 40%. The
solvent was also aften contaminated and required analysis
before reuse.
Courses of Action:
The company purchased a used distillation system for
$7,500.00 Some modifications were made to the unit for
use with their product.
Savings:
Initially this resulted in a $90,000.00 per year
savings over their previous contract fees. They also
obtained a much superior recovered solvent at a 90%
efficiency rate. They now use far more of the recovered
alcohol and also utilize the still bottoms as an asphalt
emulsifier in another product line. Total payback for
the project was approximately one month.
This project also relates to solvent recovery and
reuse possible by textile printing operations.

Case Studies for Textile Printing (5)

2009-04-15T07:53:00.002-07:00

CASE STUDIES FOR TEXTILE PRINTING
CASE NO. 5
Description: Lenoir Mirror Co. uses xylene solvent in
equipment cleanup.
Courses of Action:
The company reduced their waste costs by recovering
and reusing spent solvent on-site. Approximately 95%
solvent was recovered by distillation and still bottoms
are sent to an incinerator.
Savings:
Lenoir Mirror saves over $5,000 per year in material
and disposal costs. Total system payout will be thirteen
months.
This overall case relates to solvent recovery in
printing from screen and machine cleanups.

Case Studies for Textile Printing (4)

2009-04-15T07:53:00.001-07:00

CASE STUDIES FOR TEXTILE PRINTING
CASE NO. 4
Description: Thiele - Engdahl, Inc. uses printing inks.
In equipment cleanup the company uses isopropyl acetate.
Courses of Action
Thiele-Engdahl uses solvent twice for cleanup before
recovery and reuse. The solvent is recovered on-site
using batch distillation. Distillation bottoms are sent
off-site for disposal.
Savings:
Before the distillation system the company sent 5,000
gallons of used solvent to off-site disposal every 45 days.
Since reclaiming and reuse reduce both the volume of waste
and the volume of virgin solvents purchased, significant
savings result, paying for the distillation system in 2
years.

Cae Studies for Textile Printing (3)

2009-04-15T07:52:00.001-07:00

CASE STUDIES FOR TEXTILE PRINTING
CASE NO. 1
Description: American Colors coats or prints on fiberglass.
Waste acetone is generated during the coating or printing
process.
Courses of Action:
(1) Waste acetone is distilled and recovered at
approximately a 70% rate. This reclaimed solvent is used
in equipment cleanup.
(2) The volume of solvent has been reduced by process
modifications, especially going from light to dark coatings.
This yields an overall reduction in cleanup waste.
Savings:
American Colors cut production costs by reducing volumes
of waste solvent and reclaiming what solvent waste was
generated. The net savings were many thousands of dollars
per year.

Case Studies for Textile Printing(2)

2009-04-15T07:51:00.001-07:00

CASE STUDIES FOR TEXTILE PRINTING
CASE NO.2
Description - PCA International, Inc. is a color portrait
processing firm. PCA has undertaken a number of projects
to recover and recycle process waste especially silver
recovery.
Courses of Action:
(1) An electrolytic recovers silver from the color
negative film fixer solutions. The process results in a
96% reuse of the fixer solutions.
(2) Color developer is regenerated using an ion
exchange system. Total processing results in an 84%
recovery of the color developer solution.
(3) Spent bleach solutions are recovered and
regenerated by chemical additions, attaining 90% reuse
capability.
Savings:
PCA saves over $1.1 million each year in reusing
process solutions. Silver recovery adds another
approximate $800,000 per year.
As can be seen, this study easily relates to the
photographic processes used in textile printing screen
design and manufacture.

Case Studies for Textile Printing (1)

2009-04-15T07:48:00.001-07:00

CASE STUDIES FOR TEXTILE PRINTING
CASE NO. 1
Description - A survey of dyes in the mid 1970's showed
that 95% of the capper in an N.C. company's effluent
originated from 13 dyes. They were:
Dye
Belamine F Red 3BL
Belamine B Blue LT
Pyrazol F Violet MXD
Solantine Brown BRL
Atlantic Blue 8 GLN-K
Atlantic Resinfast Blue 2R
Sirius Supra Turquoise LG
Superlitefast Blue 2GLL
Direct Navy OFS
Belamine Red 3BL
Solophenyl Brown BRL
Fastolite Blue L
Atlantic Black NR
Percentage Cu Content
4.00
3.68
3.00
3.00
2.70
2.50
2.29
1.00
0.70
4.00
3.00
2.70
1.50
All of the previous dyes have copper as a part of the
dye molecule structure.
Possible Courses of Action:
(1) Substitute for metal containing dyes with nonmetal
dyes.
(2) Insure maximum fixation of dye by optimizing
all processing parameters such as time and temperature of
fixation, pH, salt concentration, and auxillary chemicals
content.
In this case, direct dyes with non-metal content were
substituted where possible, therefore, reducing the metal
content discharged.
PIGMENTS IN TEXTILE PRINTING
In some cases, textile printing companies may use
metal containing pigments which may not appear in the
Color Index. Here also the copper is bound as an integral
part of the chromophore molecule.
Pigment Percentage & Content
Inmont Respad Green GB3W 0.80
Inmont Respad Blue G3W 1.40
Inmont Respad Blue GH3W 1.35
Inmont Respad Blue GL3W 0.10
Inmont Respad Violet V3W 1.15
Inmont Respad Grey R3W 0.10

Reason for Scouring

2009-04-15T07:39:00.000-07:00

REASONS FOR SCOURING
REMOVE THE THICKENING AGENT
REMOVE AUXILIARIES
REMOVE EXCESS DYESTUFF
IMPROVE BRILLIANCE OF PRINT
IMPROVE FASTNESS PROPERTIES OF
PRINT
PROBLEMBACK
STAINING OF UNDYED AREAS

Auxiliary Chemicals

2009-04-15T07:34:00.000-07:00

AUXILIARY CHEMICALS
THOSE NECESSARY FOR FIXATION OF DYE INTO FIBER
REACTIVES - ALKALI
VATS - REDUCING AGENT
ACIDS - ACID
CATIONIC - ACID
DISPERSE - CARRIER
Do NOT INCORPORATE STRONG ACID, BASES, OXIDIZING AND REDUCING
AGENTS IN PRINT PASTE.
ACID AGER
LATENT REDUCING AGENTS
(SODIUM SULFOXYLATE FORMALDEHYDE)

Dyestuffs Used in Printing

2009-04-15T07:33:00.001-07:00

DYESTUFFS USED IN PRINTING
SAME AS THOSE USED IN DYEING
SPECIAL REQUIREMENTS
HIGH SOLUBILITY, DISPERSIBILITY
EXCELLENT WETFASTNESS
COTTON - REACTIVES, VATS, NAPHTHOLS
WOOL - ACID, METALIZED
NYLON - ACID, METALIZED
ACRYLIC - CATIONIC
ACETATE - DISPERSE, CATIONIC
TRIACETATE - DISPERSE
POLYESTER - DISPERSE
QIANA - ACID, DISPERSE

Step in Printing Process

2009-04-15T07:29:00.000-07:00

STEPS IN PRINTING PROCESS
1. Preparation of Print Paste
2 Printing of Fabric
3. Drying
4. Fixation of Dyestuff
5. Washing - off

Main Problems in Printing

2009-04-15T07:26:00.000-07:00

MAIN PROBLEMS IN PRINTING
COLOR - Dye and Paste Dumps; Clean-ups
METALS - Dye Dumps; Screen Making; Photo Developing
SUSPENDED SOLIDS - Print Paste and Clear Discards
SOLVENTS - Emulsion Thickeners and Clean-ups
HOT WATER - Afterwashing
BOD - Desizing; Print Paste and Clear Discards
FOAM (Floating Solids) - Carpet Printing

Waste Characteristics for Textile Printing

2009-04-15T07:25:00.001-07:00

WASTE CHARACTERISTICS FOR TEXTILE PRINTING
Hard to Treat Wastes
Color from Dyes or Pigments
Toxic Organic Chemicals
Metals
Phosphates
Dispersible Wastes
Print Paste Components
Thickeners, Binders, Humectants, etc.
Hazardous or Toxic Wastes
Metals
Organic Solvents
High Volume Wastes
Scour and Afterwash Water
(Hot, Warm and Cold)

Textile Printing

2009-04-15T07:22:00.000-07:00

Textile Printing- The application of color to a fabric in
a design or pattern (localized dyeing)
Modern printing generally incorporates one of the following
techniques:
1. Flat-bed Screen Printing
2. Rotary Screen Printing
3. Engraved Roller Printing
4. Heat Transfer Printing

Washing Agent, Washing Soda, Washing Fastness

2009-04-14T10:11:00.001-07:00

WETTING AGENT:-
A CHEMICAL THAT HELPS WATER PENETRATE A MATERIAL OR FORM A FILM OVER ITS SURFACE; USUALLY A SURFACTANT; WETTING AGENTS ARE OFTEN USED IN DYEING TO HELP THE DYE SOLUTION PENETRATE TO THE INDIVIDUAL FIBRES (THEY DON'T USUALLY HELP THE DYE PENETRATE FROM THE SURFACE OF THE FIBRE TO THE INTERIOR OF THE FIBRE.

WASHING SODA:-
IF "PURE" IS USUALLY SODIUM CARBONATE DECAHYDRATE; RETAIL WASHING SODA MAY CONTAIN ADDITIVES SUCH AS DETERGENTS, SALT AND OPTICAL BRIGHTENERS, AND IS THEREFORE NOT A GOOD SUBSITITUTE FOR SODA ASH FOR DYEING.

WASH FASTNESS:-
A MEASURE OF THE RESISTANCE OF A DYE TO WASHING OUT OF THE FIBRE; THERE ARE NUMBER OF INDUSTRY-STANDARD TESTS FOR WASH FASTNESS, USUALLY BASED ON THE EQUIVALENT TO THE HOME LAUNDYR PROCESS APPROPRIATE FOR THE FIBRE; WASH FASTNESS ARE CONCERNED NOT ONLY WITH LOSS OF DYE FROM THE COLOURED FABRIC; BUT ALSO TRANSFER OF DYE FROM THE WASH LIQUOR TO OTHER ITEMS; WASH FASTESS DEPENDS TO A GREAT EXTENT ON THE NATURE OF THE DYE, BUT ALSO ON THE FIBRE, THE APPLICATION PROCESS AND THE POST DYEING TREATMENT; THERE IS NOT NECESSARILY ANY RELATIONSHIP BETWEEN WASH FASTNESS AND LIGHT FASTNESS.

Some textile definitions

2009-04-14T10:08:00.000-07:00

ENZYME:-

A PROTEIN THAT ACTS AS A CATALYST IN A BIOCHEMICAL REACTION.

CARBONIZING:-

TREATMENT OF WOOL WITH ACID AND HEAT TO REMOVE PLANT MATERIALS.

CARRIER:-

WITH RESPECT TO DISPERSE DYES, A CHEMICAL THAT AIDS DYEING AT MODERATE TEMPERATURE.

CATALYST:-

A CHEMICAL THAT SPEEDS UP A REACTION WITHOUT ITSELF BEING CONSUMED IN THE REACTION.

FIXATION:-

FORMATION OF THE FINAL BOND BETWEEN THE DYE AND FIBRE.

LIGHT FASTNESS:-

A MEASURE OF HOW RESISTANT A COLORING MATERIAL, SUCH AS DYE, IS TO FADING DUE TO EXPOSURE TO LIGHT.

LEVELING AGENT:-

A DYEBATH ADDITIVE TO PROMOTE LEVEL DYEING.

ILLUMINATING DYE:-

DYE MIXED WITH DISCHARGE PASTE IN PRINTING TECHNIQUES; ALSO CALLED HEAD DYE.

LIQOUR:-

A SOLUTION OF DYE AND/OR OTHER CHEMICALS.

FBA:-

FLUORESCENT BRIGHTENING AGENT; ALSO CALLED OPTICAL BRIGHTENER.

PADDING:-

A DYEING METHOD WITH VERY LOW LIQUOR TO GOODS RATIO, WHERE TYPICALLY ONLY ENOUGH STRONG DYE SOLUTION IS USED TO SATURATE THE FABRIC; PADDING CAN HAVE THE ADVANTAGE OF HIGH DYE YIELD. PADDED GOODS ARE USUALLY "BATCHED"- WRAPPED IN PLASTIC AND LEFT FOR SOME PERIOD OF TIME FOR THE DYE TO ATTACH TO THE FIBRE, OR STEAMED TO FIX THE DYE QUICKLY. PADDING METHODS ARE SOMETIMES USED FOR OTHER TEXTILE PROCESSES SUCH AS BLEACHING.

POLYMER:-

A CHEMICAL IN WHICH MOLECULES ARE MADE UP OF A LARGE NUMBER OF SIMILAR REPEATING UNITS.

PIGMENT DYEING:-

COLORING FABRIC WITH PIGMENTS MIXED WITH A BINDER.

LOOM STATE:-

FABRIC IT COMES FROM THE LOOM, USUALLY BLEACHED , CONTAINING SIZE, AND MAYBE A BIT DIRTY; LOOM STATE IS ESSENTIALLY SYNONYMOUS WITH GREIGE OR GREY. SOMETIME IT MAY IMPLY THAT THE FABRIC HAS NOT BEEN INSPECTED FOR FLAWS.

SCOURING:-

THROUGH WASHING OF FIBRES OR FABRIC TO REMOVE CONTAMINANTS (DIRT, NATURAL, WAXES OR OILS).

REACTION RATE:-

A MEASURE OF HOW FAST A CHEMICAL REACTION OCCURS.

PVC:-

POLYVINYL CHLORIDE.

POUND:-

WEIGHT EQUAL TO 0.455 KILOGRAMS.

P.F.D:-

PREPARED FOR DYEING.

P.F.P:-

PREPARED FOR PRINTING.

OUNCE:-

APPROXIMATELY 28.35 GRAMS.

ORGANIC:-

A CHEMICAL THAT IS DERIVED FROM CARBON AND HYDROGEN.

CROCKING:-

TRANSFER OF COLOUR FROM DYED OR PIGMENTED FABRIC BY RUBBING; WET CROCKING REFERS TO TRANSFER OF COLOUR FROM A PIECE OF DYED FABRIC TO ANOTHER PIECE OF FABRIC, OR TO AN UNDYED AREA OF THE SAME FABRIC, WHILE THE FABRIC IS WET. DYR CROCKING MEANS THE SAME, EXCEPT THAT THE FABRIC IS DRY.

DEFIBRILLATION:-

REMOVAL OF FIBRILS FROM THE SURFACE OF A FABRIC.

DESIZING:-

REMOVAL OF SIZE FROM FABRIC; DESIZING IS AN IMPORTANT STEP PRIOR TO DYEING FABRIC, SINCE SIZE CAN INTERFERE WITH DYE UPTAKE. SOME SIZE MATERILAS WASH OUT EASILY. STARCH IS COMMONLY USED FOR SIZE, AND CAN BE QUITE DIFFICULT TO REMOVE.

DOPE DYEING:-

COLORATION OF THE POLYMER PRIOR TO MANUFACTURE OF THE FIBRE.

COUNT:-

HANKS PER POUND IS CALLED COUNT.

THE RELATION BETWEEN LENGTH AND WEIGHT IS CALLED COUNT.

AFFINITY:-

ATTRACTION BETWEEN TWO ITEMS; IN DYEING AFFINITY ESSENTIALLY MEANS THE PREFERENTIAL ATTRACTION OF THE DYE FOR THE FIBRE RATHER THAN FOR THE SOLUTION OF THE DYEBATH.

ANHYDROUS:-

WITHOUT WATER.

BARRE:-

A STRIPE-LIKE OR BAR-LIKE PATTERN IN DYED FABRIC.

BATCH(ING):-

LEAVING GOODS SATURATED WITH DYE SOLUTION FOR SOME PERIOD OF TIME, TYPICALLY HOURS, AND TYPICALLY AT ROOM TEMPERATURE FOR THE DYE TO FIX TO THE FIBRE.

Important textile knowledge

2009-04-14T10:07:00.001-07:00

1. Hue is the common name of color.
2. Value is the term used to describe lightness, darkness, tone and shade of the hues.
3. Chroma is the term used to describe the depth of color: that is dullness, brightness, saturation, intensity, vividness or purity of the color.
4. INTENSITY: The strength of a color, especially the degree to which it lacks its complementary.
5. COLOUR: Color is a sensation which occurs when light enters the eyes.
6. METAMERISM: When a dyed or printed textile material is examined under different lighting conditions, this phenomenon is known is metamerism.
7. Cellulosic and linen fabric can be recognized with the help of dilute sulphuric acid.
8. For recognizing the wool and silk fabric, caustic soda (Strong alkali) is used.
9. For recognizing the nylon fabric formic acid is used, but when nylon is mixed with another fibers.
10. For pure nylon fabric phenol is used.
11. For recognizing the polyester fabric phenol (carbolic acid) and formic acid is used.
12. For recognizing the acetate fabric acetone is used.
13. Carbolic acid (Phenol) = C6 H5 OH.
14. Formic acid = HCOOH
15. Acetone (Ketone) = CH3COCH3
16. Cellulose = C6 H10 O5
17. Glucose = C6 H12 O6
18. Manmade is hydrophobic.
19. Natural is hydrophilic.
20. For bleaching PH should be 10 to 11.
21. PILLS: Pills are short fibers like a ball which are present on the surface of fabric.
22. STELOMETER: Stelometer is a device which is used to measure strength of single fibers and single yarn.
23. Twist may be defined as no. of turns per inch is called twist per inch (TPI).
24. The unit of sound is decibel (Dba).
25. The unit of hardness is shore.
26. COUNT: Count is relation between length and weight OR Hanks per pound is called count.
27. SUBLIMATION: The process in which solids are directly converted into a gas is called sublimation.
28. HYGROMETER: The device which is used to measure the relative humidity is called hygrometer.
29. DESIZER: Following desizers are used for desizing.
1. Enzymatic -------------enzyme
2. Oxidative---------------H2O2
3. ACID-------------------H2SO4,HCL
4. BASE-------------------NaOH
.30. There are two types of sizes.
1. Natural (Starch, potato, maize, rice etc.)
2. Artificial or synthetic (PVA, PAC etc.)

.
31. MENDING: To check the surface or fault of the fabric.
32. TWILL: A fabric with diagonal parallel ribs.
33. MERCERIZING: To treat (cotton thread) with sodium hydroxide so as to shrink the fiber and increase its luster and affinity for dye.
34. SCOURING: To remove dirt or grease from (cloth or fibers) by means of a detergent.
35. SIGEING: To burn the nap from (cloth) in manufacturing.
36. NAP: A soft or fuzzy surface on fabric.
37. BLEACHING: To make white or colorless.
38. Steps of printing are ,
1. Drying 2.Fixation 3.Soaping
39. There are three styles of printing.
1. Direct 2. Discharge 3.Resist
40. Printing PH should be 5 to 5.5 but 4 to 5 is favorable.
41. Anhydrous = Without water
42. Affinity = Attraction between two items.
43. Sodium carbonate = Na2CO3 = Washing soda
44. Sodium bicarbonate = NaHCO3 = Baking soda
45. Ultraviolet light = Black light
46. Disperse dye is mainly used for polyester.
47. Glauber’s salt = Sodium sulphate
48. Muriatic acid = Hydrochloric acid. (HCl)
49. Ounce = 28.35 g
50. Urea = Carbamide CO (NH2)2
51. Acetic acid = CH3COOH = Vinegar
52. DIRECT DYES: commonly used for medium quality textiles, mainly cellulosic, may also be used for wool and silk.
53. REACTIVE DYES: Most common dye in the dyeing of cotton today because of highly fashionable color range and good fastness properties, useful for cellulosic, protein and nylon fibers.
54. SULPHUR DYES: used for heavy cotton goods as well as for linen and jute.
55. VAT DYES: Used for high quality cotton goods, special use in the dyeing of denim fabric.
56. DISPERSE DYES: Most useful for polyester, both for dyeing and printing.
57. SPANDEX: A synthetic elastic fiber of polyurethane.
58. STRIPPING: Removal of dye from fabric, it is usually done with a reducing agent such as thiox and sodium hydrosulfite.
59. TENDERING: Weakening of a fiber, normally meaning as a result of chemical degradation, cellulose fibers can be tendered by acids or by excessive action of oxidative acids.
60. UREA: It helps increases the limit of solubility of some dyes, it also increases the swelling of fibers.

Raising (Napping)

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RAISING (NAPPING):-

THE RAISING PROCESS IS A VERY OLD TECHNIQUE KNOWN ALSO TO ROMANS (AS PICTURE IN SOME PAINTINGS FOUND IN POMPEII). THIS OPERATION IS PARTICULARLY IS SUITABLE FOR WOOL AND COTTON FABRICS; IT GIVES A FUZZY SURFACE BY ABRADING THE CLOTH AND PULLING THE FIBRE END TO THE SURFACE. DURING THOSE LAST YEARS THIS PROCESS HAS ALSO BEEN APPLIED ON POLYESTER/VISCOSE BLENDS AND ACRYLIC FABRICS.
BY MEANS OF THIS PROCESS A HAIRY SURFACE CAN BE GIVEN TO BOTH FACE AND BACK OF THE CLOTH PROVIDING SEVERAL MODIFICATIONS OF THE FABRIC APPEARANCE, SOFTER AND FULLER HAND AND BULK INCREASE. THIS ENHANCES THE RESISTANCE OF THE TEXTILE MATERIAL TO ATMOSPHERIC AGENTS, BY IMPROVING THERMAL INSULATION AND WARMTH PROVIDED BY THE INSULATING AIR CELLS IN THE NAP. THE FUZZY SURFACE IS CREATED BY PULLING THE FIBRE END OUT OF THE YARNS BY MEANS OF METAL NEEDLESS PROVIDED WITH HOOKS SHELLED INTO THE ROLLERS THAT SCRAPE THE FABRIC SURFACE. THE ENDS OF THE NEEDLESS PROTRUDING FROM THE ROLLERS ARE 45 DEGREE HOOKS; THEIR THICKNESS AND LENGTH CAN VARY AND THEY ARE FITTED IN A SPECIAL RUBBER BELT SPIRAL-WOUND ON THE RAISING ROLLERS. THESE ROLLERS ARE GENERALLY ALTERNATED WITH A ROLLER WITH HOOKS DIRECTED TOWARDS THE FABRIC FEED DIRECTION (PILE ROLLER), AND A ROLLER WITH THE HOOKS FITTED IN THE OPPOSITE DIRECTION (COUNTERPILE ROLLER).

Shearing

2009-04-14T10:05:00.001-07:00

SHEARING:-

FABRICS THAT HAVE BEEN NAPPED USUALLY UNDERGO SHEARING TO GIVE THEM AN ATTRACTIVE, SMOOTH AND LEVEL SURFACE. THIS PROCESS IS VERY POPULAR WITH WOOLEN MATERIALS AS WELL AS CERTAIN COTTON FABRICS. THE FABRIC GOES THROUGH THE SHEARING DEVICE AND ALL FIBERS LONGER THAN THE SETTING ARE CUT OFF, LEAVING AN ATTRACTIVE SURFACE RESEMBLING A PILE EFFECT.

Embossing

2009-04-14T10:04:00.001-07:00

EMBOSSING:-

EMBOSSING IS A PARTICULAR CALENDERING PROCESS THROUGH WHICH A SIMPLE PATTERN CAN BE ENGRAVED ON THE CLOTH.
THE EMBOSSING MACHINE IS MADE UP OF A HEATED AND EMBOSSED ROLLER MADE OF STEEL, WHICH IS PRESSED AGAINST ANOTHER ROLLER COATED WITH PAPER OR COTTON, ITS CIRCUMFERENCE BEING EXACTLY A WHOLE MULTIPLE OF THE METAL ROLLER. A GEAR SYSTEM DRIVES THE HARMOISED MOTION OF THE ROLLERS, PREVENTING THEM FROM SLIDING AND GRANTING A SHARP ENGRAVING OF THE PATTERNED DESIGN. AFTER BEING ENGRAVED, THE PATTERN CAN BE STABILISED BY MEANS OF AN APPROPRIATE HIGH TEMPERATURE TREATMENT OR BY APPLYING SUITABLE STARCHY SUBSTANCES.

Faults for quality checker denim

2009-04-14T10:03:00.000-07:00

MAINTENANCE FAULTS:-

TEMPLE MARK
CACHE CARD PROBLEM
SELVEDGE PROBLEM
KINK'S
LASHED IN
LOOPS
OIL STAIN
STRIPS
YARN TENSION
OVER FLY
TANGLE WARP
CRACK
BATCHER PROBLEM
BATCHER CREASE
REED MARK
NOZZLE MARK
WEFT LOOSE
DROPPER SUPPORT MARK
BROKEN PICK
BATCHER RUBBING
TEMPLE MARK
STOP MARK
TEMPLE JAM
SELVEDGE CUT

PRODUCTIONS FAULTS:-

LOOSE END
TIGHT END
SHORT END
DOUBLE END
WRONG END
THICK END
THIN END
WRONG WEFT
RUBBING END
STOP MARK
CRACK
MISS PICK
DOUBLE PICK
HALF DOUBLE PICK
FLOATS
FABRIC CUT

OTHER FAULTS:-

DYEING MARK
CROSSING MARK
SIZING STAIN
HARD SIZING
COLOR VARIATION
FIBER BALLS
COUNT VARIATION
KNOTS
YARN MARK
NAPS
SLUBS
THICK WEFT
THIN WEFT

Softeners

2009-04-14T10:01:00.000-07:00

SOFTENERS:-

SOFTNESS IS OFTEN DESCRIBED AS SOUL OF THE TEXTILE ARTICLE AND CONSIDERED AS DECISIVE CRITERION FOR THE PURCHASE OF THE FINAL GARMENT.
MODERN TEXTILE FINISHING MEANS MORE THAN ONLY IMPROVING THE SOFTNESS OF TEXTILES.
FURTHERMORE SOFTENERS ARE INDISPENSABLE AS PROCESSING AGENTS E.G. FOR RAISING,SANFORIZATION AND SEWING. THEREFORE THEY ARE THE AGENTS WHICH MAKE PROCESSING POSSIBLE.

Laminations

2009-04-14T10:00:00.002-07:00

LAMINATIONS:-

FILMS WITH DIFFERENT PROPERTIES (E.G. WINDPROOF AND WATERPROOF, WATER VAPOUR PERMEABILITY),THICKNESS AND COMPOSITION (PES AND PU) TOGETHER WITH ADHESIVE SYSTEMS FOR LAMINATIONS (FILM WITH TEXTILE). PASTE-LIKE AND BREATHABLE ADHESIVE SYSTEMS FORBONDINGS (TEXTILE WITH TEXTILE).

Fashionable Coatings

2009-04-14T10:00:00.001-07:00

FASHIONABLE COATINGS:-

COMPOUNDS FOR PASTE AND FOAM COATINGS TO ACHIEVE STYLISH EFFECTS LIKE RUBBER HANDLE, PAPER HANDLE, PEARL OR GLITTER EFFECTS, SUEDE IMITATIONS, COLOUR COATINGS,WASH-OUT-EFFECTS...

Functional Coatings

2009-04-14T09:58:00.001-07:00

FUNCTIONAL COATINGS:-

COMPOUNDS FOR PASTE COATING AND FOAM COATING TO ACHIEVE EFFECTS LIKE WATER PRESSURE RESISTANCE, BREATH ABILITY, LIGHT IMPERMEABILITY, HANDLE ADJUSTMENTS... AS WELL AS SPECIAL ARTICLES LIKE WIPE COATINGS AND ANTI-SLIP SYSTEMS OR SPECIAL APPLICATIONS IN THE TECHNICAL FIELD LIKE AUTOMOTIVE, FILTER MEDIA, BUILDING MATERIALS.

Flame retardant coatings

2009-04-14T09:57:00.000-07:00

FLAME RETARDANT COATINGS:-

FLAME RETARDANT FINISHES BASED ON INORGANIC AND ORGANIC COMPOUNDS, NON-PERMANENT, FOR ALMOST ALL TEXTILES AND FOR MANY DIFFERENT KINDS OF FLAME RETARDANT STANDARDS (MVSS 302, DIN 4102 B1,...)
FLAME RETARDANT FINISHES FOR COTTON WHICH ARE STABLE TO WASHING AND DRY CLEANING ACCORDING TO THE FIRETIC PROCESS.
FLAME RETARDANT BACK COATING FOR UPHOLSTERY FABRIC ACCORDING TO THE FLAME PROTECTION STANDARD BS 5852 PART 1 AND 2. FLAME RETARDANT LIGHT PROTECTION SYSTEMS SUCH AS BLINDS, BLACK-OUT OR ROLLER BLINDS FOR DEMANDS IN ACCORDANCE WITH DIN 4102 B1 AND THE FRENCH STANDARD NF-P 92-503 FOR THE FIRE PROTECTION CLASSIFICATION M1.

DISPERSION AND AUXILIARIES

2009-04-14T09:56:00.000-07:00

DISPERSION AND AUXILIARIES:-

BINDER SYSTEM OF DIFFERENT POLYMER CLASSES AND HARDNESS RANGES. BASIS: ACRYLATE,BUTADIENE, POLYURETHANE, VINYL ACETATE AND SILICONE ELASTOMERS AS WELL AS MANY ADDITIONS FOR THE PRODUCTION OF COATING PASTES SUCH AS: FOAMING AUXILIARIES,DEFOAMING AGENTS, DISPERSION AGENTS, THICKENING AGENTS, CROSSLINKER.....

De-Aerator/Antifoam

2009-04-14T09:55:00.002-07:00

DEAERATOR/ANTIFOAM:-

AT THE COMMENCEMENT OF THE TREATMENT THERE IS OFTEN AIR IN THE TEXTILE WHICH HAS TO BE ELIMINATED FROM THE FIBRE FOR THE OPTIMAL WETTING WITH LIQOUR. INCLUSION OF AIR, PARTICULARLY ON HIGH SPEED MACHINES AT A HIGH TURBULENCE, CAUSES FOAM FORMATION. BY THE APPLICATION OF DEAERATOR/DEFOAMER THE INTERFACIAL TENSION BETWEEN TREATMENT LIQOUR AND FABRIC IS REDUCED AND THEREFORE A SPONTANEOUS WETTING OF THE MATERIAL IN A NON FOAMING APPLICATION IS POSSIBLE.

Wetting agents and detergents

2009-04-14T09:55:00.001-07:00

WETTING AGENTS AND DETERGENTS:-

DETERGENTS ARE MIXTURE OF NON IONIC AND / OR ANIONIC SURFACTANTS WHICH SEPARATE SOILING SUBSTANCES FROM THE FABRIC AND KEEP THEM IN FINE DISTRIBUTION IN THE BATH. ANOTHER IMPORTANT TASK OF DETERGENTS IS THE ELIMINATION OF OILY SOILINGS. APART FROM THEIR MAIN FUNCTIONS CONCERNING FOAMING AND WETTING, DETERGENTS HAVE TO FULFIL SPECIFIC DEMANDS SO THAT THEY CAN BE APPLIED ON MODERN MACHINES.

Enzymatic Pre-cleaning

2009-04-14T09:54:00.001-07:00

ENZYMATIC PRECLEANING:-

AMYLASES ARE MOST OFTEN APPLIED IN DESIZING OF WOVEN FABRIC TO DECOMPOSE STARCH SIZES. FURTHERMORE SPECIAL ENZYMES LIKE PECTINASES AND/OR HEMACELLULASES ARE APPLIED IN PRE TREATMENT TO OBTAIN AN OPTIMAL CLEANING OF THE MATERIAL.

Shelf Life

2009-04-14T09:53:00.000-07:00

SHELF LIFE:-

THE PERIOD OF TIME SOME PRODUCT CAN BE STORED "ON THE SHELL" BEFORE IT DEGRADES TO SOME POINT OF REDUCED EFFECTIVENESS; SOME CHEMICALS, INCLUDING DYES, HAVE LIMITED SHELF LIFE,THEY DEGRADE OVER TIME, EVENTUALLY BECOMING COMPLETELY USELESS FOR THEIR INTENDED PURPOSE.

Soaping Or Soaping Off

2009-04-14T09:52:00.002-07:00

SOAPING (OR SOAPING OFF):-

WITH RESPECT TO DYEING, THE PROCESS WASHING DYED FABRICS WITH VERY HOT (OFTEN BOILING) WATER WITH SURFACTANTS AND SOAP TO REMOVE DYE THAT IS NOT FIXED TO THE FIBRE; SOAPING OFF IS IMPORTANT PARTICULARLY WITH SOME REACTIVE DYES, SINCE A GOOD DEAL OF HYDROLYZED DYE IS LOOSELY BONDED TO THE FABRIC, AND MUST BE REMOVED TO AVOID STAINING OF OTHER GARMENTS OR FABRIC IN LAUNDERING; SOAPING IS ALSO IMPORTANT IN VAT DYEING, WHERE THERE ARE ACTUAL CHANGES, INCLUDING HUE,IN THE DYE IN THE FIBRE; THOUGH SURFACTANTS ARE OFTEN USED, THEY MAY ACTUALLY CONTRIBUTE ALMOST NOTHING TO THE EFFECTIVENESS OF THE PROCESS.

Sizing

2009-04-14T09:52:00.001-07:00

SIZING:-

IN TEXTILES, A MATERIAL APPLIED TO YARNS OR FABRICS TO MAKE THEM STIFFY OR TEMPORARILY BIND FIBRES TOGETHER; SIZING IS USED EXTENSIVELY, SPECIALLY FOR CELLULOSE FIBRES, TO MAKE THEM EASIER TO PROCESS OR PROTECT THEM FROM DAMAGE DURING HIGH SPEED WEAVING; A WIDE VARIETY OF COMPOUNDS, INCLUDING STARCHES AND OTHER PLANT DERIVATIVES, AND SYNTHETIC ORGANIC COMPOUNDS, SUCH AS POLYVINYL ALCOHOL, ARE USED FOR SIZING. SIZING MATERIALS CAN INTERFERE WITH DYEING; SO IT IS IMPORTANT THAT THEY ARE REMOVED BY DESIZING, USUALLY PRIOR TO SCOURING BUT SOMETIMES AS PART OF THE SCOURING PROCESS.

Color Kitchens

2009-04-14T09:50:00.000-07:00

COLOUR KITCHENS:-

THE COLOUR KITCHEN CAN BE A MANUAL SYSTEM WHERE ALL THE OPERATIONS FOR PREPARING THE THICKENER, WEIGHING THE DYES AND THE AUXILIARIES, DISSOLVING AND PREPARING OF MASTER BATCHES AND CUTTING PASTES IS MANUALLY CARRIED OUT BY THE OPERATORS WORKING ON THE COLOUR KITCHEN.
THIS APPROACH TO WORK ENTAILS SOME PROBLEMS BOTH FOR HEALTH PROTECTION AND RESULTS; SMALL INACCURACIES, MOMENTARY DISTRACTION OF THE OPERATOR AS WELL AS DIFFERENT WAYS OF WORKING OF VARIOUS OPERATORS CAN COMPROMISE THE REPRODUCIBILITY OF RESULTS.
NOW MANY MANUFACTURERS USE AUTOMATIC COLOUR KITCHEN BOTH FOR SAMPLING AND PRODUCTION PURPOSES. IN THESE COLOUR KITCHENS THE VARIOUS MASTER BATCHES AND THE CUTTING THICKENERS ARE STORED IN BIG CONTAINERS FROM WHICH THEY ARE AUTOMATICALLY TAKEN BY MEANS OF PUMPS TO BE THEN USED OR TO PREPARE THE CUTS. SPECIAL AUTOMATIC DISTRIBUTION SYSTEMS CAN REPRODUCE THE STORED RECIPES (BY RECALLING THEM BY MEANS OF THE KEYBOARD) AND ACCURATELY WEIGH, BLEND AND MIX THE COMPONENTS.
IN SEVERAL COLOUR KITCHENS THE BALANCE INCORPORATING THE CONTAINER FOR PREPARING THE PASTES IS PLACED ON A TROLLEY, WHICH IS MOVED AUTOMATICALLY UNDER THE DISPENSER NOZZLE OF THE CONTAINERS (FOR CUTTING AND BLENDING THE VARIOUS MASTER BATCHES). IN OTHER COLOUR KITCHENS DISTRIBUTION NOZZLES ARE ASSEMBLED ALL TOGETHER ABOVE THE BALANCE. THE PRODUCTS MUST BE PERFECTLY BLENDED BEFORE USE.

Dyed and Pigments

2009-04-14T09:48:00.000-07:00

DYES AND PIGMENTS:-

COLORANTS ARE USED IN TEXTILES TO GIVE COLOUR TO TEXTILES.
THESE ARE CHEMICAL KNOWN AS DYES AND PIGMENTS.
THE MOST COMMON OF THESE ARE DYES.
THERE ARE HUNDRED OF DYES AVAILABLE FOR USE IN MANUFACTURING; THE MOST COMMONLY USED OF THESE CATEGORIES ARE:

DIRECT DYES:-

A CHEAP AND LOW COLOUR FAST DYE USED ON CELLULOSICFIBRES, (SUCH AS COTTON, FLAX, RAYON ETC); THEY OFFER A WIDE RANGE OF COLOURS, BUT THE COLOURS MAY NOT BE AS BRIGHT OR INTENSE AS DESIRED. THESE DYES MAY BE LOSE COLOUR IN WASHING AND LAUNDERING.

REACTIVE DYES:-

USED ON CELLULOSIC FIBRES (COTTON,RAYON), PROTEIN FIBRES (WOOL,SILK) AND NYLON. THESE DYES OFFER GOOD COLOUR FASTNESS AND VERY BRIGHT COLOURS ARE POSSIBLE. REACTIVE ARE MOST POPULAR DYESTUFF IN THE WORLD.

VAT DYES:-

CAN BE USED ON COTTON, ACRYLIC AND NYLON. THESE ARE CONSIDERED TO BE THE MOST COLOURFAST OF ALL DYE CLASSES.THEY ARE USED IN TEXTILE PRODUCTS REQUIRING COLOURFASTNESS TO COMMERCIAL LAUNDERING WITH HIGH TEMPERATURES AND POSSIBLY BLEACH. (EXAMPLES: UNIFORMS, COMMERCIAL LINES, ETC.

ACID DYES:-

USED ON NYLON, SPANDEX AND SOME SPECIALIZED ACRYLICS. THESE DYES OFFER A WIDE RANGE OF BRIGHT COLOURS, BUT THE COLOUR FASTNESS VARIES WITH THE DIFFERENT DYES IN THE CLASSIFICATION.

CATIONIC OR BASIC DYES:-

USED PRIMARILY ON ACRYLIC. THESE DYES PRODUCT BRIGHT COLOURS WITH EXCELLENT COLOUR FASTNESS.

DISPERSED DYES:-

USED ON POLYESTER, NYLON, ACETATE AND OTHERS, A GOOD RANGE OF COLOUR IS AVAILABLE WITH THESE DYES BUT COLOUR FASTNESS CAN VARY CONSIDERABLY.

PIGMENTS:-

ANOTHER IMPORTANT CATEGORY OF COLORANTS USED IS KNOWN AS PIGMENTS. MOST DYES ARE DISSOLVED IN WATER, ABSORBED INTO THE FIBRES, BUT PIGMENTS ONLY LIE ON THE SURFACE. THEY DO NOT ADHERE TO THE FABRIC WITHOUT A RESIN BINDER. THIS BINDER WHICH IS USUALLY MIXED WITH THE PIGMENT, ACTS LIKE AN ADHESIVE. THE TWO MOST COMMON USES FOR PIGMENTS ARE PRINTING OPERATIONS AND SOLUTION DYEING OF THE POLYMER MELT PRIOR TO EXTRUSION OF SOME SYNTHETIC FIBRES.

How is color defined?

2009-04-14T09:47:00.001-07:00

HOW IS COLOR DEFINED?

THREE VALUES ARE USED TO DEFINE A COLOR: FIRST IS THEHUE, SOMETIMES CALLED SHADE, SECOND IS THE CHROMA AND THE THIRD IS THE LIGHTNESS. EVERY COLOR CAN BE DESCRIBED USING THESE THREE VALUES AND TAKING THE TYPE OF LIGHT INTO CONSIDERATION. THIS IS THE BASIS OF COLORIMETRY.

DIFFERENT SHADES OF COLOR ARE ARRANGED IN A HUE CIRCLE RUNNING CLOCKWISE FROM YELLOW THROUGH ORANGE, RED, VIOLET, BLUE, BLUISH GREEN AND GREEN BACK TO YELLOW AGAIN. A COLOR SHADE MAY BE LIGHTER OR DARKER DEPENDING ON ITS LIGHTNESS. IF THE CHROMA OF A COLOR IS REDUCED, THEN THIS COLOR WILL BE LESS BRILLIANT (CLOSER TO GRAY). IF THE SATURATION IS ZERO THEN WE TALK OF AN ACHROMATIC COLOR. BLACK, WHITE AND ALL OF THE INTERMEDIATE SHADES OF GRAY ARE ACHROMATIC COLORS, DETERMINED BY THEIR LIGHTNESS.

What are color differnces?

2009-04-14T09:45:00.002-07:00

WHAT ARE COLOR DIFFERENCES?

MANY INDUSTRIES THAT USE COLORING PROCESSES HAVE TO SUPPLY PRODUCTS THAT ARE THE SAME COLOR AND THAT LOOK THE SAME, MEANING THAT DEVIATIONS FROM THE ORIGINAL OR THE STANDARD HAVE TO BE AS SLIGHT AS POSSIBLE. IN PRACTICE IT IS IN MOST CASES NOT POSSIBLE TO MATCH THE COLOR OF A PRODUCT 100%, AS EVEN THE SAME SAMPLE (E.G. A T-SHIRT) WILL EXHIBIT MINIMAL COLOR DIFFERENCES IN DIFFERENT PLACES, ALTHOUGH THESE ARE NOT VISIBLE TO THE HUMAN EYE.
COLOR DIFFERENCES SUCH AS THESE CAN BE MEASURED AND RECORDED USING COLORIMETRY. IN ORDER TO ESTABLISH THE COLOR DIFFERENCE BETWEEN TWO SAMPLES, THE COLOR COORDINATES OF THE STANDARD AND THE MATCH ARE ENTERED IN A COLOR SPACE. THE DISTANCE BETWEEN THE TWO POINTS AS ENTERED REPRESENTS THE COLOR DIFFERENCE OF THE TWO SAMPLES.
THE CIELAB COLOR SYSTEM AND COLOR DIFFERENCES ARE USED HERE IN MOST CASES.
DE* REPRESENTS THE TOTAL COLOR DIFFERENCE, WHICH IS MADE UP OF THE DIFFERENCES IN CHROMA, DC*, (MORE BRILLIANT / DULLER), HUE, DH*, (GREENER, YELLOWER, BLUER, REDDER ...) AND LIGHTNESS, DL*, (LIGHTER OR DARKER). THE TOTAL COLOR DIFFERENCE CAN ALSO BE MADE UP OF THE DIFFERENCE IN LIGHTNESS, DL*, A*, DA*, AND B*, DB*.

What is color?

2009-04-14T09:45:00.001-07:00

WHAT IS COLOR?

WITHOUT LIGHT THERE IS NO COLOR: LIGHT FALLS ON AN OBJECT AND, DEPENDING ON THE COLOR OF THE OBJECT, IS PARTIALLY ABSORBED. THE LIGHT THAT IS NOT ABSORBED IS REFLECTED AND FALLS ON THE COLOR RECEPTORS IN THE EYE. THESE CONVERT THE INCIDENT LIGHT INTO STIMULI, WHICH ARE THEN SENT VIA NERVES TO THE BRAIN. HERE THE STIMULI ARE INTERPRETED, AND A COLOR PERCEPTION IS FORMED.

WITH REGARD TO SENSORY PERCEPTION: EACH PERSON "EXPERIENCES" COLOR DIFFERENTLY. THIS IS NOT JUST BECAUSE NO TWO EYES ARE IDENTICAL, BUT ALSO BECAUSE COLOR INTERPRETATION ALSO VARIES FROM PERSON TO PERSON. THE SAME PERSON CAN EVEN PERCEIVE COLORS DIFFERENTLY AT DIFFERENT TIMES AND ACCORDING TO THE MOOD HE OR SHE IS IN.

MANY PEOPLE PERCEIVE COLORS INDEPENDENTLY OF LIGHT. FOR EXAMPLE, IN ONE FORM OF SYNESTHESIA WHERE COLORS ARE HEARD NOTES, HARMONIES AND MUSIC ARE LINKED WITH CERTAIN COLORS: HIGH NOTES MOSTLY WITH LIGHT COLORS AND LOW NOTES WITH DARK COLORS.

What are color mixtures?

2009-04-14T09:44:00.000-07:00

WHAT ARE COLOR MIXTURES?

A DISTINCTION IS MADE BETWEEN TWO BASIC TYPES OF COLOR MIXTURES: ADDITIVE AND SUBTRACTIVE. ADDITIVE COLOR MIXTURES WERE DISCOVERED IN 1860 BY MAXWELL. THE TERM MEANS THAT EVERY COLOR CAN BE PRODUCED BY MIXING TOGETHER IN DIFFERENT QUANTITIES RED, GREEN AND BLUE (R,G,B) COLORED LIGHT. IF THE THREE COLORED LIGHTS, - RED, GREEN AND BLUE, - ARE MIXED IN EQUAL PROPORTIONS, WHITE LIGHT IS OBTAINED. ADDITIVE COLOR MIXTURES ARE USED IN ELECTRONIC IMAGE PROCESSING AND IN TELEVISION TECHNOLOGY, WHERE PHOSPHOR DOTS THAT EMIT RED, GREEN AND BLUE LIGHT ARE EMBEDDED IN THE SHADOW MASK OF THE SCREEN. THE DOTS OF COLORED LIGHT CANNOT BE SEEN INDIVIDUALLY BECAUSE THEY ARE SO TINY, SO AN ADDITIVE COLOR MIXTURE IS FORMED AND THIS COLOR IS WHAT IS PERCEIVED.

HOWEVER, PIGMENTS AND DYES RATHER THAN LIGHTS ARE USED TO COLOR MATERIALS. IF THE THREE PRIMARY COLORANTS CYAN, MAGENTA AND YELLOW (C, M,Y) ARE MIXED IN EQUAL QUANTITIES, BLACK IS OBTAINED. THIS IS CALLED A SUBTRACTIVE COLOR MIXING. THIS IS BECAUSE COLORANTS SUCH AS DYES AND PIGMENTS ABSORB SOME OF THE INCIDENT LIGHT AND SUBTRACT IT FROM THE REFLECTED LIGHT. ADDING COLORANTS MAKE THE MATERIAL DARKER. SUBTRACTIVE COLOR MIXING OCCURS IN PHOTOGRAPHIC COLOR REPRODUCTION, PRINTING AND COLORING TEXTILES, PLASTICS, PAPER AND GLASS.

What is metamerism?

2009-04-14T09:43:00.000-07:00

WHAT IS METAMERISM?

EVERYONE IS FAMILIAR WITH THIS EFFECT: A COLORED OBJECT APPEARS TO BE ONE COLOR UNDER A GIVEN ILLUMINANT, (E.G. DAYLIGHT), BUT APPEARS DIFFERENTLY UNDER ANOTHER ILLUMINANT SUCH AS THE LIGHT FROM AN INCANDESCENT LIGHT BULB. THIS CHANGE IN COLOR, WHICH OCCURS FREQUENTLY WITH ALMOST ALL COLORED OBJECTS, HAS BEEN ERRONEOUSLY CALLED METAMERISM. BUT WHAT IS THE TRUE DEFINITION OF METAMERISM?

WE USE THE TERM METAMERISM WHEN THE COLORS OF TWO OBJECTS UNDER THE SAME ILLUMINANT, E.G. DAYLIGHT, (D65) ARE PERCEIVED TO HAVE THE SAME COLOR UNDER ONE ILLUMINANT, SUCH AS DAYLIGHT, BUT HAVE DIFFERENT COLORS UNDER A DIFFERENT ILLUMINANT, SUCH AS AN INCANDESCENT LIGHT BULB. THIS IS USUALLY AN UNWANTED EFFECT. JUST IMAGINE YOU HAVE A BLUE JACKET AND THE MATERIALS USED FOR THE SLEEVES AND BACK EXHIBIT METAMERISM THE JACKET WOULD LOOK PERFECT IN DAYLIGHT, BUT IN THE EVENING IN THE LIGHT FROM AN ELECTRIC BULB THE SLEEVES WOULD APPEAR TO BE A COMPLETELY DIFFERENT COLOR.

THIS EFFECT CAN BE EXPLAINED CLEARLY USING THE STANDARD COLOR VALUES XYZ, WHICH REPRESENT A COLOR PERCEPTION. TWO SAMPLES ARE IDENTICAL IN A CERTAIN LIGHT IF THEIR XYZ VALUES FOR THIS TYPE OF LIGHTING ARE IDENTICAL. THIS IS THE CASE WHEN WE HAVE SAMPLES WITH IDENTICAL SPECTRAL REFLECTANCE CURVES. HOWEVER, METAMERIC SAMPLES HAVE DIFFERENT SPECTRAL REFLECTANCE CURVES. THE TWO CURVES WILL HAVE THE SAME X, Y AND Z VALUES AND HAVE THE SAME COLOR UNDER ONE ILLUMINANT, BUT DIFFERENT X, Y AND Z VALUES AND DIFFERENT COLORS UNDER A DIFFERENT ILLUMINANT.

What are tolerances?

2009-04-14T09:42:00.000-07:00

WHAT ARE TOLERANCES?

NO PAIR OF SAMPLES HAS 100% IDENTICAL COLOR VALUES, AND YET SUPPLIERS HAVE TO SATISFY THE CUSTOMER'S QUALITY REQUIREMENTS FOR COLOR ACCURACY WHEN SUPPLYING PRODUCTS. WE ALSO KNOW THAT A HUMAN BEING'S PERCEPTION OF COLOR IS VERY SUBJECTIVE.

IT IS THEREFORE IMPORTANT THAT SUPPLIERS AND CUSTOMERS USE COLORIMETRY TO STIPULATE COLOR TOLERANCES, THE MAXIMUM COLOR DIFFERENCES WITHIN WHICH PRODUCTS WILL STILL BE ACCEPTED.

COLOR TOLERANCES CAN BE ESTABLISHED IN ALL COLOR SYSTEMS, INCLUDING THE CIE XYY SYSTEM OR THE CIELAB SYSTEM, WHICH IS THE ONE MOST FREQUENTLY USED. HOWEVER, THE DISADVANTAGE OF THE TRADITIONAL SYSTEMS IS THAT VISUALLY THESE DO NOT HAVE EQUIDISTANT SPACING. WHAT DOES THIS MEAN? IN THE CIELAB SYSTEM, FOR EXAMPLE, YOU COULD ESTABLISH THAT A MAXIMUM COLOR DIFFERENCE OF DE*=1 IS ACCEPTABLE. HOWEVER, WHEN ASSESSING VARIOUS PAIRS OF COLORED SAMPLES WITH A MEASURED COLOR DIFFERENCE OF DE*=1, YOU FIND THAT DE*=1 MAY WELL BE AN ACCEPTABLE COLOR DIFFERENCE WITH BRILLIANT YELLOW OR GREEN TONES, BUT WITH ACHROMATIC, GRAY COLORS DE*=1 REPRESENTS ANOTHER, UNACCEPTABLE COLOR. THE SAME MATHEMATICAL DIFFERENCE OF 1 DOES NOT THEREFORE CORRESPOND TO OUR VISUAL PERCEPTION.

SEVERAL NEW TOLERANCE FORMULAS HAVE BEEN DEVELOPED IN ORDER TO AVOID HAVING TO ESTABLISH DIFFERENT COLOR TOLERANCES IN THE CIELAB SYSTEM FOR EVERY COLOR. THESE FORMULAS CORRECT THE NON-EQUIDISTANT SPACING OF THE CIELAB SYSTEM. TODAY THE MOST COMMON PUBLISHED TOLERANCE FORMULAS ARE THE CMC AND THE CIE-94 FORMULAS. HOWEVER, THESE ARE MORE OFTEN BEING REPLACED BY MORE RECENT TRANSFORMATIONS SUCH AS DIN99 OR CIEDE2000.

What is whiteness?

2009-04-14T09:41:00.000-07:00

WHAT IS WHITENESS?

WHITE IS A COLOR TOO. ALTHOUGH IT IS ACHROMATIC, IT IS STILL A COLOR IN THE COLORIMETRIC SENSE. WITH AN IDEAL WHITE, ALL THE INCIDENT LIGHT IN THE 400-700 NM RANGE IS REFLECTED. THIS "IDEAL WHITE" IS, HOWEVER, PURELY A THEORETICAL QUANTITY. BARIUM SULPHATE, WHICH WAS ONCE WIDELY USED AS A WHITE STANDARD, "ONLY" GIVES AN AVERAGE REFLECTION OF 98% ACROSS THE VISIBLE SPECTRUM.

"WHITENESS THAT IS, HOW WHITE A MATERIAL IS IS A YARDSTICK FOR QUALITY FOR MANY TYPICALLY WHITE MATERIALS SUCH AS PAPER OR TEXTILES. THE "WHITENESS" OF A MATERIAL CAN ADMITTEDLY COME VERY CLOSE TO AN IDEAL WHITE IF THE MATERIAL IS BLEACHED, THUS DESTROYING THE COLOR PIGMENTS THAT ABSORB LIGHT. BUT IF A WHITE NEEDS TO BE "BRIGHT" THEN OPTICAL BRIGHTENERS ARE USED TO OBTAIN A "PERFECT" WHITE. THESE OPTICAL BRIGHTENERS, WHICH ARE ALSO FOUND IN EVERYDAY LIFE IN WASHING POWDERS AND TOOTHPASTES, FOR EXAMPLE, HAVE PROPERTIES THAT ENABLE THEM TO ABSORB RADIATION IN THE UV RANGE (<400> 400 NM). MATERIALS THAT HAVE BEEN TREATED WITH AN OPTICAL BRIGHTENER CAN THEREFORE HAVE A REFLECTION VALUE OF >100%. THESE MATERIALS APPEAR TO BE "BRIGHT" WHITE.