Hi Val, Yes, you're making sense. The effect I'm looking for would need to be subtle, but its presence, I think, would help to visually isolate the guardrails from the rest of the concrete bridge structure. I want the guardrails to be obviously different than the bridge. Yes, I will be mixing different shades of concrete for each, with the guardrails being a bit darker and yellower, the bridge being lighter and tanner/greyer. The spectrum of color of concrete seems infinate. The splatter effect using a toothbrush is one I had considered, although I had thought of a stiff bristled paintbrush, I think the toothbrush is better. How silly is this: I had thought of it but not tried it because I felt the result would be to "large". I will however try it this weekend, what is the worst that can happen, paint them over?