10-17-2015, 12:59 PM
Hi jd, and 
to Big Blue - it's good to see you here.
As for the paint, I honestly don't recall. I may have started with PollyScale's "Aged Concrete", but I usually just dump in a little of this and a little of that, until it looks acceptable to my eye. The only time I make a record of a colour mix is when it's to match a specific prototype, such as a colour for a diesel or unusual freight car. For example,I've painted hundreds of freight cars, and few, if any, used a "boxcar red" right out of the bottle. Even for those painted in the same session, I will alter the colour as I paint, so that only a few will be the same. And of course, once they've been weathered, it would be difficult to find an exact match.
I'm not sure what you have in the way of paint on-hand or what's currently available, but I'd suggest that you check out prototype examples in your area (take photos, if possible) and then select a paint which is close. I don't really understand too deeply the machinations of colour mixing, but I seem to have a pretty-good natural affinity for it , so it's difficult for me to suggest specific colours you might use to alter the basic colour with which you choose to work. While you can lighten with white and darken with black, other light or dark colours can also accomplish changes - for example, yellow will shift red to orange, depending on how much you use.
When you look at prototype concrete, try to forget any preconceived ideas about what colour it should be, and instead look at the colour it actually is. Some new concrete looks pretty grey, but older stuff is seldom grey at all - try starting with a light grey (easier to darken a paint than lighten it), then add some yellow - do this on a scrap of plastic or other impermeable surface, using "brushloads": dip a brush in your basic colour 2 or 3 times, deposit it on the plastic, then wipe the brush (no need to fully clean it), and quickly dip it once into the yellow, and stir that, using the brush, into the grey. How does it look? What do you think it needs? Since you're not using great amounts of paint, it's easy to simply play at this until you start to see how the colours work with one another.
Another option is to use paint which has been labelled by the manufacturer as "Concrete" (aged or not) and either use it as-is or alter it, then, once your concrete work is dry and fully cured, alter it further with weathering. For weathering, you can use a wash of thinned paint (if water-based, adding a drop of dish detergent to the thinned paint will allow it to flow more readily) or weathering powders, or you can use an airbrush.
If your first attempts at colouring the concrete or weathering it are not to your liking, don't be afraid to go back and redo it. A concrete pier has little in the way of details which will be obliterated by more paint.
Oh, and one more thing: if you're in the U.S., your paint will have no "u" in its colour. As far as I know, that won't affect your results.
Wayne
to Big Blue - it's good to see you here. As for the paint, I honestly don't recall. I may have started with PollyScale's "Aged Concrete", but I usually just dump in a little of this and a little of that, until it looks acceptable to my eye. The only time I make a record of a colour mix is when it's to match a specific prototype, such as a colour for a diesel or unusual freight car. For example,I've painted hundreds of freight cars, and few, if any, used a "boxcar red" right out of the bottle. Even for those painted in the same session, I will alter the colour as I paint, so that only a few will be the same. And of course, once they've been weathered, it would be difficult to find an exact match.
I'm not sure what you have in the way of paint on-hand or what's currently available, but I'd suggest that you check out prototype examples in your area (take photos, if possible) and then select a paint which is close. I don't really understand too deeply the machinations of colour mixing, but I seem to have a pretty-good natural affinity for it , so it's difficult for me to suggest specific colours you might use to alter the basic colour with which you choose to work. While you can lighten with white and darken with black, other light or dark colours can also accomplish changes - for example, yellow will shift red to orange, depending on how much you use.
When you look at prototype concrete, try to forget any preconceived ideas about what colour it should be, and instead look at the colour it actually is. Some new concrete looks pretty grey, but older stuff is seldom grey at all - try starting with a light grey (easier to darken a paint than lighten it), then add some yellow - do this on a scrap of plastic or other impermeable surface, using "brushloads": dip a brush in your basic colour 2 or 3 times, deposit it on the plastic, then wipe the brush (no need to fully clean it), and quickly dip it once into the yellow, and stir that, using the brush, into the grey. How does it look? What do you think it needs? Since you're not using great amounts of paint, it's easy to simply play at this until you start to see how the colours work with one another.
Another option is to use paint which has been labelled by the manufacturer as "Concrete" (aged or not) and either use it as-is or alter it, then, once your concrete work is dry and fully cured, alter it further with weathering. For weathering, you can use a wash of thinned paint (if water-based, adding a drop of dish detergent to the thinned paint will allow it to flow more readily) or weathering powders, or you can use an airbrush.
If your first attempts at colouring the concrete or weathering it are not to your liking, don't be afraid to go back and redo it. A concrete pier has little in the way of details which will be obliterated by more paint.
Oh, and one more thing: if you're in the U.S., your paint will have no "u" in its colour. As far as I know, that won't affect your results.
Wayne