Pigment identification and technical analysis of works of art provide the historian and conservator with information that allows a new view of an object. The methods the analyst chooses depends on the nature of the sample and the materials and method expected for the age of the object being examined. Several analytical methods are used frequently in the museum field with great success; these include x-ray fluorescence spectroscopy, x-ray powder diffraction methods and optical microscopy. Results from the analysis of pigments in paintings by Derain, Beckman, El Greco, G. David, and Gentileschi are given. The results include discovery of an unpublished formulation of cobalt violet, example of the use of particle size to change the appearance of color, and the use of x- ray fluorescence to determine artists' palettes without removing samples from the works of art. The study of the El Greco and the Gentileschi show how technical investigations can complement art historical research.