MIDTERM_FORENSIC_88

• Paints

  are a mixture of pigment and a suitable liquid to form a closely adherent coating when spread on a surface in a thin coat.
• Primer


  is a preparatory coating put on materials before applying the paint itself.
• Paint thinner

  is a solvent used to thin oil-based paints or clean up after their use.
• Acrylic Paint

  this is extremely versatile, and ideal for fine brushwork, glazing, staining, water media techniques and many more.
• Oil-Based Paint


  it is very durable and provides A glossy-looking finish.
• Watercolor Paint


  it is a translucent paint containing pigment and a binder, typically gum-arabic.
• Watercolor

  refers to both the medium and the resulting artwork. Addition, the term “watercolor paints” refer to paints that use water soluble, complex carbohydrates as a binder.
• Gouache Paint

  it is a water-soluble and opaque paint so the white of the paper surface does not show through.
• Encaustic Paint


  it is a wax-based paint with a strong color pigment
• Pigments

  are finely ground particles that are dispensed into paint and provide color and hiding properties.
• Prime Pigments

  are those that contribute to both wet and dry hide in paint.
• Titanium dioxide TiO2

  is the most-costly pigment and it contributes directly to a paint wet hide, while providing whiteness.
• Colorants

  are prime pigments that provide actual color within the can.
• Organic Colorants


  provide brighter colors.
• Inorganic Colorants

  are the duller, earthy colors and are more durable for exterior painting application.
• Extender Pigments


  are lower cost pigments that give extra weight or bulk up to the paint.
• Binders

  are ingredients that provide a binding effect that holds the pigments together to create a dry film on the surface.
• Solvents


  are the vehicle for allowing paint to get from the can to the surfaces and these types of liquids differ depending on the type of paint.
• Additives


  are used in paints to create additional performance properties
• Thickening agents


  provides “viscosity” are additional thickness so the paint can be applied properly
• surfactants or soaps

  provides paint stability so the paint would not separate and also keeps the pigments dispersed in the liquid to allow for better hiding power and additional assurance for color accuracy.
• Biocides


  in latex paints, there are two types of biocides used, a preservative to keep bacteria from growing; and a mildewcide to discourage mildew growth
• Defoamers

  provides a way to break bubbles as they are formed during the paint manufacturing process…
• Co-solvents


  provides additional liquids to the water and can assist the binders in forming a good film when applied in cold temperatures.
• Sample Description


  It is the first step in forensic paint analysis. It is the visual and macroscopically evaluation, description, and documentation of the original condition of the sample or samples.
• Physical Match

  The most conclusive type of examination that can be performed on paint samples is the physical matching of samples.
• Sample Preparation and Layer Analysis

  The layers in a paint film are identified by viewing the sample edges at magnifications ranging between 5x and 100x.
• Solvent or Micro Chemical Tests

  have long been used for attempting to discriminate between paint films of differing pigment and binder composition that are otherwise similar in visual and macroscopically appearance,
• Polarized Light Microscopy (PLM)

  is appropriate for the examination of layer structure as well as either or both the comparison or identification of particles present in a paint film including pigments, extenders, additives, and contaminants.
• Infrared Spectroscopy (IR)


  This may be used to obtain information about binders, pigments, and additives used in various types of coating materials.
• Raman Spectroscopy


  This can also be used to obtain information about binders, pigments, and additives used in coatings. Because this technique is based on light scattering rather than absorption, this provides information that is complementary to that produced by infrared spectroscopy.
• Pyrolysis Gas Chromatography (PGC)

  is a destructive technique that uses pyrolytic breakdown products to compare paints and to identify the binder type.
• Micro Spectrophotometer

  Color analysis has a long history in the pigment, paint, dyestuff, and fabric industries and has led to numerous approaches to color measurement and description.
• Scanning Electron Microscopy (SEM)

  can be used to characterize the morphology and elemental composition of paint samples.
• X-Ray Fluorescence Spectrometry


  is an elemental analysis technique based upon the emission of characteristic X-rays following excitation of the sample by an X-ray source.
• X-Ray Diffraction (XRD)

  is a nondestructive technique for the identification of the crystal form of pigments and extenders or fillers.
• Paint

  is a complex mixture consisting of pigments, modifiers, extenders, and binders.
• binder

  is a natural or synthetic resin that helps stabilize the mixture and form of a film when it is spread.