Adobe 65007312 User Guide - Page 34

USING PHOTOSHOP LIGHTROOM 2 29 Workspace and setup Monitoring processes The activity monitor displays over the identity plate when Lightroom is busy with a task. • To cancel a process, click the X beside the progress bar. • To switch and view another process in progress, click the triangle beside the progress bar. Color management More Help topics "Setting print resolution and color management" on page 158 About color management in Lightroom Lightroom simplifies color management in your photographic workflow. You don't need to choose color settings or color profiles until you are ready to output your photos. To take advantage of Lightroom color management, you need to calibrate your computer monitor so that you are viewing accurate color. See "Calibrate and profile your monitor" on page 30. Color spaces, color profiles, and tonal response curves It's not necessary for you to understand how Lightroom manages color internally, but the following information may be useful in your workflow. A color space describes a range or gamut of colors. Various devices in your photographic workflow have different color gamuts in which they can record, store, edit, and output photos. A color profile defines a color space so that Lightroom knows how to manage and convert colors in your photo. Raw photo files do not have embedded color profiles in Lightroom. For raw files, the Develop module assumes a wide color space based on the color values of the ProPhoto RGB color space. ProPhoto RGB encompasses most colors that cameras can record. A color profile is also defined by a gamma value, or more accurately, its tonal response curve. The tonal response curve defines how tonal values in the raw image are mapped. To provide useful information in the histogram and RGB value display, Lightroom assumes a gamma value of approximately 2.2. More accurately, it uses a tonal response curve similar to the tonal response curve of the sRGB color space. While Lightroom uses a tonal response curve to provide information for the histogram and RGB values, it manipulates the raw data before it is tone mapped. Working in this linear gamma avoids many of the artifacts that can result in working with a tone-mapped image. The Library module stores Low and Medium quality previews in the Adobe RGB color space, and High quality previews in ProPhoto RGB. These previews are also used when printing in draft mode. For rendered files such as TIFF, JPEG, and PSD files, Lightroom uses the image's embedded color profile to display the image, histogram, and color values. If the image doesn't have a profile, Lightroom assumes the sRGB profile, and the image may not look as expected on your monitor. Updated 03 September 2009