If your goal is a blue you see on a display—phone, TV, monitor—you’re working in an additive color system. In that system, blue is produced when the “blue channel” dominates. Depending on how you run the color, it often involves turning on blue plus at least one other light component for brightness or tint.
One common two-color rule-of-thumb people use with screens is: blue + white. White isn’t a pigment; it’s essentially a mix of multiple light components. Add “white” light to blue light and you get a lighter, more saturated-to-pastel range of blue.
Why “blue + white” is a real two-color recipe (for light)
“White” here means a neutral, full-spectrum light that boosts the brightness without changing the basic hue. Many digital tools implement this idea using RGB values: you keep blue high, and you raise other channels together to move from deep blue toward a lighter blue.
In other words, it’s not that you generate pure blue from two totally unrelated colors. It’s that blue light plus neutral light (white) gives you a stable “blue” output in practice.
