How to change the color of a house paint?

Oldcyclingguy wrote: 

I am trying to make the colors black and white similar to the color swatches I created. The black does not look black?

Getting colors like black and white to look right in a photo often goes beyond just knowing Photoshop. You have to apply a knowledge of how light interacts with it, like how a fine art painter would be trained to. For example, black paint is not absolute solid black. In reality it’s going to be slightly color-tinted shades of very dark gray, depending on the reflectivity of the paint.

In the original photo, look at the black part of the first floor and the black framing on the garage doors. Measure the color values there in Photoshop with the Info panel. You will notice that what looks “black” actually varies quite a lot and is often not even neutral, depending on what the reflective elements in the black paint are reflecting from the ambient light and the color of surrounding surfaces.

White is the same way. Even though very light area of the building on the first floor was painted with a single color, you will find that the color values on various parts of it vary greatly depending on whether it’s in light of shadow, and what colors in surrounding areas are being reflected by the paint.

To “apply” simulated paint over the house realistically but quickly, you can still add a solid color on another layer, but you will probably want to apply a layer blending mode such as Color, Darken/Multiply (for white), or Lighten/Screen (for black), so that the color you apply can look more convincing by blending in with how the light in the scene interacts with the surfaces of the real building.

As for masking it, that will probably require a mix of manual and semi-automatic methods that are combined. It looks it could be done with some passes with the Quick Selection tool combined with some fast straight lines drawn with the Pen tool that are converted to selections.

Your first job would be to create an accurate mask. That might involve the Polygonal Lasso Tool or a Curves modification of a copy of the  * b *  channel of Lab Color as seen in the  very rough sample above. Both require additional patient brushwork.  

I see that you marked off an area and Filled with Black with the Blending Mode set to Color, and it produced a gray rather than the Black you expected. The reason is that when the Blending Mode is set to Color, the tone level of the existing color is unchanged -- a lighter value,  lighter than maximum black. To change both color and tone while maintaining modeling requires another approach. I find it convenient to make that adjustment in Lab Color mode where color and tone level reside in different channels. There are other ways to achieve the same result.      

Most likely you must use some of the selection techniques with manual work included. I think that automated options can not make perfect selection in your case.

After isolating area you can use Hue/Saturation adjustment for your task: remove Saturation entirely, drag slider to the far left then drag Lightness slider to the left to achieve dark look or black color paint.

For white coor paint drag Lightness slider to the right.