Descriptions of Calculate blending options You can select various blending methods in the Calculate Image dialog box. Normal. Places Source 1 over Source 2 at the specified opaci- ty. 100 percent opacity replaces Source 2 with Source 1. Multiply. Creates a darker channel than the source chan- nels. Black areas in either source create black areas in the result- ing channel. White areas do not affect the result. Screen. Creates a lighter chan- nel than the source channels. White areas in either source cre- ate white areas in the resulting channel. Black areas do not affect the result. Overlay. Places Source 1 over Source 2 without destroying the shadows or highlights of Source 2. Soft Light. Lightens or darkens pixels in Source 2 depending on the brightness value of the cor- responding pixels in Source 1. Pixels in Source 1 that are light- er than 50% black lighten Source 2. Pixels in Source 1 that are darker than 50% black dark- en Source 2. Hard Light. Lightens or darkens pixels in Source 2 depending on the brightness value of the cor- responding pixels in Source 1. Hard Light works similarly to Soft Light. However, black in Source 1 produces black in the resulting channel and white pro- duces white. Darken. Replaces pixels in Source 2 with the correspond- ing pixels in Source 1, if the pix- els in Source 1 are darker. Lighten. Replaces pixels in Source 2 with the correspond- ing pixels in Source 1, if the pix- els in Source 1 are lighter. Add. Creates a lighter channel than the source channels. Add is similar to Screen but usually produces a higher-contrast image. If you select the Add option, you can enter a Scale value from 1 to 2 with a precision of three decimal places. To calcu- late the average brightness val- ue of two channels, choose Add and enter a Scale of 2. You can brighten or darken the resulting channel by specifying an Offset value. To lighten the overall image, enter an offset from 1 to 255. To darken the image, enter an offset from -1 to -255. Subtract. Creates a darker channel than the source chan- nels. Subtract is similar to Multi- ply. However, corresponding pixels of the same color pro- duce black in the resulting chan- nel. If you select the Subtract option, you can enter a Scale value from 1 to 2 with a preci- sion of three decimal places. You can brighten or darken the resulting channel by specifying an Offset value. To lighten the overall image, enter an offset from 1 to 255. To darken the image, enter an offset from -1 to -255. Difference. Compares the color value of each pixel in Source 1 with the corresponding pixel in Source 2, subtracts the darker value from the lighter, and then uses this difference in the result- ing channel.
Canvas 8 Help: Image filters and effects (19 of 20)                                                 Page #725