White-light photomicrographs

In a study of the fluorescence properties of the Brazil Block seam (Parke Co., IN), a somewhat different approach was used. In this case, about a hundred individual spectra were taken on a variety of fluorescing liptinite macerals. Although the macerals from which the spectra were tkane were not identified at the time of measurement, photomicrographs in both normal white-light and fluorescent light were taken for documentation. The spectral parameters for each spectrum were calculated and these data were subjected to cluster analysis to test the degree to which the... 

Figure 2.4 (Upper) White-light (polarized) photomicrograph, in reflected mode, of an suspension with a significant emulsified oil content. With polarized light, the clays (C) appear bright, but the oil droplets cannot be seen at all. (Lower) In this reflected-light photomicrograph, of the same field of view as above, the fluorescence mode shows bright oil droplets in a dark water-continuous phase. In this photograph the clays cannot be seen. From Mikula [66], Copyright 1992, American Chemical Society.

Figure 16. Photomicrograph (white light, reflected mode) illustrating trapped air bubbles at the cover-slip-sample interface. These can easily be mistaken for the dispersed phase, especially in transmitted-light mode.

Figure 18. White-light (polarized) photomicrograph in reflected mode of an oil-in-water emulsion with a significant solids content. With polarized light, the clays (C) appear bright, but the oil droplets cannot be seen at all.

Figure 21. White-light (top) and blue-light fluorescence mode (bottom) photomicrographs of a water-in-oil emulsion. With white light the water droplets have internal reactions that lead to a halo effect and an incorrect size estimate. With incident blue—violet light to excite oil-phase fluorescence, the emulsified water droplets appear as dark circles in a bright oil background and are significantly easier to size. However, droplets that are above or below the plane of focus will still be incorrectly sized.

Fig. 5. Photomicrograph of dedolomite (poikilotopic spar calcite) from the Pheil No. 3 well, Atascosa County, 2253 m, white light. Width of field is 940pm. Note that many of the dolomite rhombs are badly corroded where they have been unreplaced by the spar.

Figure 5. Photomicrograph of mammillary calcite in cross-polarized light. Note the closely packed comb structure of the crystals with the teeth (T) of the comb meeting the back (B) of the comb at an acute angle. White arrow indicates direction to the substrate.

Figure 12. Foliar growth is commonly discontinuous. This photomicrograph (plane polarized light) displays two well-developed discontinuities (black arrows) caused by accumulations of silt and clay-sized debris, topped by numerous small seed crystals that mark resumption of deposition. The white arrow points toward the substrate. Up is toward the viewer.

Figure 1. Light microscopy photomicrograph of radial section of white oak (Quercus alba group) from unidentified marine wreck from New Brunswick Canada. Iron salts have precipitated inside pits (5-p.m diameter) on the radial walls of small vessels and in ray parenchyma cells.

Figure 8 shows photomicrographs of the various stages of stepwise thinning of a microscopic, horizontal oil film stabilized by asphaltene particles (7 vol%) in a 1 1 volume mixtiue of n-heptane and toluene. At a film thickness greater than about 300-nm, the asphaltene particles inside the film form a random structure which causes the white and dark interference patterns produced in reflected monochromatic light to form a mosaic structure (Fig. 8a). The film is irregular. After a while, a white expanding spot surrounded by a dark rim appears inside the film with a thickness of about 100-nm (Fig. 8b). Here, one can see that the film thickness at the spot area appears to be much more reg-...

Plan Apo (plan apochromatic) Corrected for spherical aberration and spectral continuity. These objectives may contain up to 15 separate lenses, as reflected in their price. For black-and-white photography and under the correct lighting conditions, a Plan lens may equal a Plan Apo lens in resolution. However, for color photomicrographs, the latter is preferred. 

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