 # LRGB Blending

In this lesson we take a closer look at the techniques used to adjust the blend between Luminance and Color data via LRGBCombination. This step of creating a color image is not typically given much thought and fraught with undesirable results. A generalized model followed by a few examples is shown in this recording.

See below the video for some additional information.

Here is the Pixel Math Expression to generate the color bars:

### Expression

R/K: iif(inrect(x0,y0,width,height),.1,0.02)

G: iif(inrect(x0,y0+300,width,height),.1,0.02)

B: iif(inrect(x0,y0+600,width,height),.1,0.02)

### Symbols

x0=0,

y0=300,

width=4096,

height=200

If desired, you can download my image that compares the variations of RGB image processing

The expression to create a horizonal gradient is simply X().  This is a function that outputs the horizontal position as normalized value between 0 and 1. So if the x position is  25% across the image (from the left) then the x value is 0.25. Since I am writing this number to the view- it becomes the brightness value. So I will have a range of values from 0 (left side) to 1 (right side)- thus making a horizonal gradient.