Thursday, January 14, 2010

Computer Color Matching Systems

CCM Basics
Colour theory :-
Basics of color perception and Measurement
Light and color
Color and light Knowledge
Colour difference,
Measuring color in textiles click here
Color Evaluation
Test Methods for color measurements
The right choice of measuring geometry


Instruments (इंस्ट्रुमेंट्स)
Spectrophotometers and colorimeters
Instruments for measuring light and color Read here
Difference between a colorimeter and Spectrophotometer
Colorimeter
  • Comparatively low price
  • Compact Size
  • Simple operation
  • Better mobility
Spectrophotometers (Features of spectrophotometers)
  • Expensive
  • high precision
  • more versatile
  • accurate color measurement
  • suitable for complex color analysis
  • can measure color strength and metamerism
Instruments for color measurement
Selecting a spectrophotometer
Recipe Formulation
Making Primary data
Improving Upon the Data
Recipe Optimization Criteria
Improving reproducibility of dyeing
Quality control
Shade passing Or color Difference evaluation
Color Tolerances for Consistent Pass/Fail Decisions

  • Disadvantages of Visual Pass/Fail Systems
  • Requirements of a Computerized Pass/Fail Program
  • Numerical Basis of Computer Pass/Fail Data
  • Pass/Fail Tolerances Using CIELAB DL*, Da*, Db*
  • Pass/Fail Tolerances Using CIELAB DL*, DC*, DH*
  • Pass/Fail Tolerances Using CIELAB DE*
  • Pass/Fail Tolerances Using The CMC Formula
  • Implementing CMC Pass/Fail 
Measuring Special colors
Measuring Fluorescent colors Read here Fluorescence and color
When a fluorescent color is measured by the spectrophotometer, the spectral power distribution of the light source, including the ultraviolet regions, must be controlled.

Measuring Mettalic colors
when measuring metallic colors, it is more effective to measure and evaluate them with a spectrophotometer that measures color at multiple angles
Measuring Powder objects

When measuring powder with a spectrophotometer, the measurement value varies depending on the density of the powder and the surface conditions. To avoid errors, special methods are required such as placing a fixed amount of powder into a container of a fixed shape and size and maintaining a fixed surface quality.
If the size of the particles is large, use a spectrophotometer which has a large measurement area, so the measurement surface is averaged and repeatable measurement values can be obtained.
Measuring Transparent objects
The measurement of semi-transparent objects requires special consideration because the light might pass through the material and the measurement may be influenced by what is behind the object. To solve this problem, increase the thickness of the object to prevent the light from being transmitted completely. Another solution is to put an opaque white surface behind the object.
Measuring Objects Containing Patterns
When measuring objects that have patterns or textures, the measurement value varies according to the location if a small area is measured. The largest possible measurement area should be used, or measurements should be taken several times in different locations and then the average measurement value should be calculated.


Color measurement for package dyeing
Whiteness/ yellowness Indices
whiteness index
Yellowness index
Strength evaluation of dyes,
Colorfastness



  Useful Readings to Improve efficiency of Color Matching System
Datacolor Video Tuturials on color matching system
introduction to color technology
Video 1 
Video 2
Video 3



Database Preparation for Successful Computer Color Matching Part 2
Database preparation for computer color matching Click here
Measurement methods for textile fabrics click here
Color Measurement Method and Effect of sample presentation
Understanding Color Management and Software in Textile Printing A presentation
Color Management and RIP Software for Digital Textile Printing Managing Color for Optimal Results

Seven Steps to Superior Color Control in the Dyehouse:By Eric Alho, Product Manager Textile Software
Generic dyeing and color matching Click Here
Improving computer control of batch dyeing operations Click here

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