Analyzing Exposure Differences

You can analyze the differences in exposure in your frame sequence:

1.   Select Image > CurveTool to add a CurveTool node after the image sequence you want to analyze.
2.   Add a Viewer after the CurveTool.
3.   Under Curve Type, select Exposure Difference.
4.   From the channels dropdown menu and checkboxes, select the channels you want to analyze.
5.   If you want to analyze an area in the frame rather than the entire frame, define a region of interest either by dragging the edges of the frame box to a new position in the Viewer, or by defining the area using parameters labeled ROI.
6.   To analyze the sequence, click Go!. The Frames to Execute dialog opens.
7.   Specify the frame range you want to analyze. Enter the first frame, followed by a comma and the last frame. Click OK. Nuke now performs the analysis.
8.   You can find the results of the analysis on the IntensityData tab where the parameter input fields have turned blue to indicate they are animated. To see the animation curve, right-click on one of the input fields and select Curve editor....

Once Nuke has created the animation curve, you can copy the animation or any of its values into a color correction node, for example, to match the analyzed exposure there. Ctrl/Cmd+click on the animation button and drag and drop it to another parameter to create an expression linking the two.