Authigenic carbonates (aragonite, calcite, and dolomite) are present in various morphologies, as nodules or irregular precipitates, and are designated as "C" in the "Diagenesis" column of the core description forms ("barrel sheets") (Figs. F4, F5). In cases where it was possible to clearly identify the carbonate mineralogy, symbols for the respective carbonate minerals were used (see Fig. F3). The degree of lithification is noted in the core description as "friable" (the rock showed only partial lithification) or "lithified" (the rock is fully cemented).
In the core section dialogue box, we set the subbottom depth (SBD) of section at zero for Section 1 and let it automatically increment down the remaining sections for each core. All images were acquired at a crosscore and downcore resolution of 100 pixels/cm. At the beginning of Leg 204, the acquisition aperture was varied in an attempt to maximize the dynamic range captured. However, after Site 1244, we found it more expedient to fix the aperture at a value that would image most cores without the need for further adjustment. It was, therefore, normally set to f4.7, which maximized the dynamic range for most of the core sections, but it had to be decreased when bright ash-rich or carbonate layers were imaged to prevent image saturation. To prevent saturation of the bar-code label (placed at the end of each section) and of the polystyrene inserts (e.g., for voids and whole-round samples), we placed pieces of dark overhead-transparency film over them to reduce the brightness. This was a satisfactory but inelegant solution that would be improved with some high-quality gray translucent overlays. Care was taken to ensure that the system was correctly calibrated using the "white tile" procedure and that the camera position was correctly set up. If the image field is incorrectly set such that the ruler on the left side of the core is in the camera's field of view, then horizontal stripes, caused by pixel blooming, occur on the resulting image, which results in relatively dark cores. This is caused by the bright nature of the lettering on the ruler and could be prevented by having darker lettering (gray instead of white). Output from the DIS includes an uncompressed TIFF file (available upon request) and a compressed Mr.Sid (.sid) file (available in the Janus database) for each scanned section. Red-green-blue (RGB) profiles for all images were also automatically saved (available upon request) but were generally not used on board. Additional postprocessing of the color imagery was done to achieve a "medium"-resolution JPEG (.jpg) image of each section and a composite PDF (.pdf) image of each core. The PDF full-core color images were useful for quick reference at sea, particularly when writing the site chapters.
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