AVS Special Member
Join Date: May 2008
Location: San Francisco - East Bay area
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Gamma doesn't change the "intensity" of the primary colors... at all. Gamma defines how bright each grayscale step should be. That luminance curve you posted... the reference line will change shapes (more or less curvature) when you enter higher or lower gamma targets in your calibration software. I use 2.25 for the gamma target nearly 100% of the time because studios mastering Blu-ray discs are using workstations setup for gamma in the 2.2-2.3 range. When your measured gamma perfectly matches your gamma target, the 2 curves in that graph will be right on top of each other. Small variations there won't be visible in images, but the closer every grayscale step is to the desired 2.25 gamma, the better your images will look.
Samsung gamma controls actually change the luminance of grayscale steps and in doing that, the control will change the shape of the measured curve in your graph. It looks like you have a fairly well-selected gamma setting right now. If you set the Gamma control to a higher number (like 2.5), your measured gamma curve will dip down below the reference curve for your 2.25 gamma target. If you set the Samsung Gamma control for a lower numeric gamma, the measured curve will be above the reference curve defined by your 2.25 gamma target. Higher numeric Gammas will make every measured point from 10%-90% darker than the 2.25 reference gamma (Gamma does not affect the position of 100% or 0%, only the steps between 0% and 100% are affected). When the images look darker than they should because of a too-high (numerically) gamma, images aren't as satisfyingly bright as they should be. When you select a numeric gamma lower than the 2.25 reference gamma target, images will be brighter, but they also lose dimensionality and look "flatter" than they should when gamma is correct.
"Movies is magic..." Van Dyke Parks
THX Certified Professional Video Calibration
Widescreen Review -- Home Theater & Sound