Autodesk 62205-051408-9001 User Guide - Page 730

27 Adding and Removing Grain 6. Enable Exclusive to show the selected channel as grayscale. This is useful when viewing the blue channel, as the eye is less sensitive to blue than to other colors. When you enable Exclusive, Red is enabled (selected for display) by default. Click Blue or Green to show either of these channels. Note: While Exclusive is enabled, any changes made in step 5 (disabled channels) are ignored; you only see the one channel. When you disable Exclusive, all channels become enabled again. 7. Disable Proportional below the fields to adjust the channels independently. You can apply changes to all channels simultaneously by enabling Proportional, but adjusting each one individually is far more accurate. 8. Drag the appropriate RGB Gain field to increase or decrease the color value for the selected channel. The RGB Gain fields are translated as scaling factors for the built-in granularity curves. The range of values is from 0 to 10. Note: To scale the granularity curve using only the gain, use the Match Grain picker when you choose a film stock (in step 3). (When you use Match Grain with the Custom option, the sample determines the granularity curve itself.) To learn how to use the Match Grain picker, see Matching Grain. 9. Drag the appropriate X Radius and Y Radius fields for the selected channel to change the horizontal or vertical size of the grain. The range of values is from 0 to 100. 10.After setting the Gain and Radius values for the necessary channels, check the result in various regions of the image (for example, shadows, midtones, and highlights). 11.You can compare the grain in the image to either the same image with another Add Grain setup or another image from the workspace. For information on the Compare tool, see Using the Compare Tool. Using Custom Granularity Curves When you use the Custom option in the Film Stock list, you can use the curve editor to build a granularity curve from scratch. Usually, when you use the Custom option, you build granularity curves from grain that you want to match. Thus, the curve editor (and the other controls for the Custom option) are described in detail in Matching Grain. To build a granularity curve from scratch: 1. Follow the procedure described in Matching Grain, but skip the step Analyze the Grain. 2. Instead of using the Match Grain feature, simply modify the curves in the necessary areas. Note: If you use the Custom option because your film stock is not listed, you may be able to get the required granularity curve data from the film manufacturer (for example, Kodak). Applying Grain with a Uniform Spatial Distribution Normally, the spatial distribution of grain is different for each channel of a color. However, if you choose B/W from the Film Stock list, the grain will have the same spatial distribution for all three channels. The RGB gain fields are still enabled and can be used to give a tint to the grain (useful when re-graining sepia images). Similarly, the RGB radius fields can still be adjusted so you can have different size and orientation for the three channels. 714