Here's the example photograph toned using a light brown shade (159, 122, 42).
This method applies the solid color evenly over your image. A variation of the Solid Color method is using a mask to selectively tone your image.
Here's the result of:
Both images used (159, 122, 42) as the fill color. You can see that the toning in the second photograph looks much deeper. That's because the mask applies the color fill more heavily in the shadows than in the highlights.
This method is similar to the Gorman method in that they both use a shadow mask to add toning to the image.