Color measurements gloss

Similar to cleaning operations, consolidation and adhesion treatments are usually under analytical control. Measurements of the chemical, morphological, and physical properties of the consolidated material are indispensable to assure the efficiency of the operation. Changes in mechanical strength, color, and gloss, as well as chemical composition are assessed. Studies of stability of consolidants are frequently performed by means of namral and accelerated aging trials. 

Optical properties are of most relevance for plastics, although color and gloss can be important for any of the material classes for products where aesthetic considerations are of intere.st. In fact for most plastics products it is the aesthetic properties, such as surface texture, color, gloss, and reflectance, that are important. Light transmission characteristics and refractive index measurements are needed for only a relatively few products such as lenses and windows where the transparency or transluccncy of the material is a paramount consideration. This is unfortunate, as light transmission and refractive index are a good deal easier to define and and to correlate with visual experience than the other properties mentioned. Meeten [I] has edited a detailed text on the optical properties of polymers. 

The measurement and control of color and gloss parameters is critical because of aesthetic reasons and provides an indirect measure to control process parameters. The impression gloss consists of several appearance phenomena - specular gloss, haze, DOI and surface smoothness. The evaluation of surface smoothness has major influence on the total appearance and is currently only evaluated visually. The presented new measurement technique correlates with the visual assessment of orange peel and objectively measures surface smoothness. The measurement results of the new orange peel instrument (long - and short-term waviness) were related to different process parameters, such as substrate roughness, in an actual case study. 

Color measurement cannot be divorced from our simultaneous perception of other specimen characteristics (43) such as gloss and haze. Instrument measurements will also be affected by these other specimen attributes. It is... 

Fig. IZ Specular transmission refers to light passing through an object without diffusion. Specular transmission measurements are widely used in the chemical analyses and color measurements of liquids. Potentially, appearance attributes important for specular transmission should be roughly analogous with gloss attributes associated with specular reflection (from HunterLab).

This means unwanted variation in density, color or gloss in print. The size and intensity of the variations are measured. Print density variations (graininess 0.5-2 mm mottle 2-8 mm) are measured from an even black and/or cyan tone of at least 40% and as an average of eight images with a size of 51 x 51 mm. ... 

The method relies on the instrumental measurement of the degree of yellowness under daylight illumination of close to colorless or close to white translucent or opaque plastics. The measurement is made on pellets and is based on the tristimulus values that are obtained with a colorimeter. Methods are provided to determine the color measurements, such as yellowness index, CIE X, Y, Z, and Hunter L, a, b, or CIE L, a, b. A series of specimens that is compared should have similar gloss, texture, etc. 

Many times, the optical clarity of nanocomposite can be seen by looking through films produced with these materials. But optical properties can be evaluated by different techniques, such as gloss, haze, and color measurements and UV-visible spectrophotometry. Furthermore, optical analysis such as optical microscopy can be applied to verify the dispersion of the particles in a matrix that can be related to transparency of the nanocomposites. All these techniques applied on nanocomposites based on polymeric matrix and different kinds of nanoparticles are discussed and illustrated in this chapter. 

Transparency, gloss, color, refractive index, and reflectance are the properties normally associated with aesthetics of plastic materials. In some areas, changes in optical properties, increases in haze after abrasion testing (285), color differences after weathering, and birefringence analysis of residual stress within a transparent part (286) are all used to measure the effects of applied stresses. Measurements of color, gloss, refractive index, and haze apply to many products beyond plastics and use similar techniques. Reference should be made to this general topic for detailed information (see Color). 

It is noted that the spectral characteristics of the light source are not critical unless highly chromatic low-gloss materials are tested or specular reflectance produces an obvious shift in the color of the incident light. It is also noted that if transparent materials are tested it must be possible to measure up to 200 gloss units. 

These instruments do not collect or incorporate the specular reflectance of a sample into the measurement. This measurement is typical of the view the human eye may have of a sample by excluding the specular energy. For example, when viewing a high gloss fype of sample you can usually determine a point where the reflection of the light is mirrored or reflected directly back at your eyes. This makes it difficult, as well as uncomfortable, to see any detail of the color of the sample. By tilting the sample either away from you or towards you, you can... 

Conversely, if those two samples are measured with a sphere instrument with the specular component included, the instrument results will be very similar. By including all of the reflection from the sample, the instrument cannot detect differences in samples due to texture or gloss and will identify the color with the same pigmentation, as being the same. Even though... 

The color development then continues at the paint companies. As the paint companies compete for the assembly plant business they submit sample batches to be tested, retested and tested some more at pilot operations around the world. Beside color adhesion, durability, DOI, gloss, orange peel and any other number of performance factors are studied. When the studies are complete and a color is proven feasible a designated paint company is then challenged to make hundreds (even thousands) of sample panels. But first, a measurement should be taken to insure these are the proper color. 

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