Uday Kale - Recipe Prediction for Non Textile Application - Datacolor_2.pdf
- 1. RECIPE PREDICTION IN PIGMENTED APPLICATION 1 UDAY KALE DATACOLOR MUMBAI
- 2. Company History Since 2009 Datacolor is a stand alone, pure play, publically traded company on the Swiss stock exchange. Before 2009, Datacolor was part of the Swiss based Eichhof Holding. The sale of 2 of the 3 companies owned by the Holding allowed Datacolor to be well positioned financially to pursue its growth strategy. 2
- 3. A Global Business United States United States China (Suzhou) Switzerland United Kingdom France India Taiwan Italy Germany Belgium Hong Kong China (Shanghai) Corporate functions Corporate functions Sales and Service office Representation – 65 countries Employees – 300 in 25 counties 3
- 4. Brands that rely on Datacolor The names, trademarks, service marks, logos and icons of the above companies are properties of the respective companies. 4
- 6. Kubelka - Munk 6 Behaviour of light Incident light Specular %R Diffuse %R (=color) Internal %R Absorbed light
- 7. Complex Subtractive Mixing Turbid-Media Theory • Kubelka-Munk • K/S is proportional to concentration • In the opaque case: K/S = ((1-r)*2)/2R K/Smix = (c1K1 + c2K2 + c3K3 ...) / (c1S1 + c2S2 + c3S3 ...) • The full treatment: • Others Both Light Absorption and Light Scattering are considered.
- 8. Kubelka Munk Relation When light passes through a film ( Plastic or Paint) it gets absorbed, Reflected, Scattered or Transmitted. The passes of light through such film is very complex and the mathematical description for the phenomenon is known as “ Turbid Medium Theory”. Kubelka and Monk simplified the Turbid Media Theory. When the light passes through the pigment layer, the changes take place in downward and upward direction (Two fluxes one in downward and other in upward direction) This can be calculated using simple mathematical relation from their scattering and absorption coefficients. ( K and S) Kubelka Monk equation co relates reflectance of an object with Scattering and Absorption coefficients. K/S = ( 1 –R )2 / 2R
- 9. Kubelka Munk Relation The most important feature of K M Relation is it is additive. i.e. K/S is additive while Reflectance is non additive. K/S function is linearly proportional with concentration of colorants. K/S = α c where α is a constant of proportionality. Pigments disperse in polymers have both the properties of absorption and scattering hence it is necessary to calculate both the coefficients. Such application is termed as Two constant Application. In case of Textile dyes particles are in dissolved state hence not capable of scattering. In this case the scattering is contributed by substrate only. We need to calculate only absorption coefficient ( K ) for the colorant Such a application is called one constant application.
- 10. Kubelka - Munk 10 Kubelka-Munk Function K/S = 2R (1-R)2
- 11. Matching 11 Matching colors makes it possible to determine which colorants are needed and which are their optimal quantities to reproduce the color.
- 12. Matching - General 12 To be able to do a formulation, we need to define the following things mathematical: colorants standard Mathematical relation
- 13. Matching - General 13 + = 39.20% + 52.55% = 32.87% Reflection doesn’t fit the additive principle
- 14. Kubelka - Munk Solution for the problem: KUBELKA - MUNK Function
- 15. Kubelka - Munk Application of the Kubelka – Munk function 15 K/S = 0.6855 K/S = 0.2142 K/S = 0.4713 K/S mixture = 0.6855 The K/S function is additive.
- 16. Matching - General 16 Formulate the color of the standard is the same as reproduce the spectral curve by using a combination of colorants
- 17. Colorant set Define the behaviour of the pigments in a colorant set so we can match the target. 17
- 18. Matching The quality of the matches is directly related to the quality of your primary samples! 18
- 19. Colorant set One constant function (transparent) Two constant function • Relative (opaque) • Absolute (translucent) 19
- 20. One constant function One constant function 20 Transparent colorant set
- 21. One constant function Used to match: Transparent or translucent samples that not include a white pigment. If white is used, it is used in a fixed amount. Example: woodstains, transparent inks, textiles,... 21
- 22. One constant function 22 Substrate Color layer Due to the nature of the colorant, the colorant absorbs but don’t scatter light.
- 23. Two constant function Two constant function 23 Opaque and translucent colorant set
- 24. Two constant function 24 Substrate Due to the nature of the colorant, the colorant selectively absorbs and scatters light.
- 25. Two constant function Separated K & S values are calculated for the colorant 25
- 26. Two constant relative Used for opaque applications Substrate is not important Film thickness is not important 26
- 27. Two constant absolute Used for opaque and non opaque samples Substrate is important Film thickness is important 27
- 28. Saunderson Correction The Kubelka-Munk color model doesn’t take into account the reflection losses at the sample boundaries. There are two losses that Saunderson takes into account: • Internal loss (internal %R) • External loss (surface %R – diffuse and specular) 28
- 29. Saunderson Correction 29 Behaviour of light Incident light Surface Specular %R Diffuse %R (=color) Internal %R Surface Diffuse %R
- 30. Saunderson Correction Note: When we create a colorant set, we modify the measured reflectance before calculating K and S values of the colorants. 30 Rc = Rm - ke 1 – ke – ki * (1 – Rm)
- 31. Matching 31 Substrate isn’t important Film thickness isn’t important Will perform an opaque match Fix the pigment loading if wanted Opaque Matching
- 32. Matching 32 Fixed pigment loading Opaque Matching
- 33. Matching 33 Opaque Matching Defined pigment load is reached
- 34. Matching 34 Substrate is important Film thickness is important You can do a CR match You can do a fixed % load match Translucent Matching
- 35. Matching 35 Translucent - CR Match No pigment load defined Defined CR
- 36. Matching 36 Requested CR is achieved Free pigment loading Translucent - CR Match
- 37. Matching 37 No opacity defined Fixed pigment loading Translucent - Fixed % Load match
- 38. Matching 38 Translucent - Fixed % Load match Calculated opacity Requested pigment loading is reached
- 39. Matching 39 Matching programs may calculate many recipes for a new shade For each recipe the computer gives: Color difference Metamerism Price ... The colorist then selects the most suitable recipe considering: Fastness properties Compatibilty ...
- 40. Matching Why don’t my predictions come out right first time? 40
- 41. Matching 1. Theory assumes colorants behave the same in combination as individually in the database. Does not account for interaction. 2. Pigments can differ form the ones used to create the colorant set 3. Reproduciability 4. Errors in sample preparation 5. Appearance 41 Error in database Error in lab sampling DE* = 0.5 DE* = 0.5 New Shade Recipe Prediction Lab Sampling
- 42. What is Smartmatch? Smartmatch quantifies the interaction between individual pigments and substrates (Axis Smartmatch) Smartmatch is a self learning matchprediction system based on practical experience (Palette Smartmatch) Smartmatch is a function to correct matching theory (single constant, two constant or multi constant theory (combined method))
- 43. Smart Calibrator selects the best optical model (combined vs pairs) Smart Calibrator
- 44. Performance factors Eveluate how the colorants perform in the current batch Based on a comparison between the amount of colorant you put into the formula and the amount of colorant the system ‘sees’ in the formula. 44
- 45. Performance factors The colorant can perform 3 ways: • PF = 1.0 Colorant is performing exactly as expected • PF > 1.0 Colorant is performing stronger than expected • PF < 1.0 Colorant is performing weaker than expected 45
- 46. Gloss Compensation The gloss problem 46 The lack of agreement between visual and instrumental evaluations (with integrating sphere spectro’s) of color samples that have different gloss
- 47. Gloss Compensation When to use gloss compensation? Batch (or product) gloss is differentthan the gloss of the standard. Biggest effect for dark colors. 47 Gloss compensation offers the ability to more accurately match, correct, and control color, even as the gloss of the standards and the product differ
- 48. New Feature Match and correct to an offset value of the original target in (CIE L*a*b*, D65) Utilize common target for color appearance matching of samples with various gloss and texture. CIE L*a*b* Offset