It isn't a style preference, it's a signal-to-noise argument. If everything on the screen is saturated, then color carries no information: a real alarm doesn't stand out because the green pipe next to it is just as loud. ISA-101 pushes the normal state to low-contrast grays specifically so that the only saturated color on the screen is an abnormal condition, which the eye finds instantly.
The canonical background is a mid gray (~#C8C8C8) with white for operative areas. Equipment is drawn in grayscale. You reserve red/orange/yellow/blue strictly for alarm priorities and green/gray for run/stop. Nothing is colored just because it's water or gas.
The way to sell it to management: put the two screens side by side and trigger one alarm on each. On the busy screen people hunt for it; on the calm screen it jumps out. That demo wins the argument every time.
Background on the philosophy is in /standards/isa-101.html and the exact palette with hex values is in /learn/hmi-color-palette.html
The canonical background is a mid gray (~#C8C8C8) with white for operative areas. Equipment is drawn in grayscale. You reserve red/orange/yellow/blue strictly for alarm priorities and green/gray for run/stop. Nothing is colored just because it's water or gas.
The way to sell it to management: put the two screens side by side and trigger one alarm on each. On the busy screen people hunt for it; on the calm screen it jumps out. That demo wins the argument every time.
Background on the philosophy is in /standards/isa-101.html and the exact palette with hex values is in /learn/hmi-color-palette.html