Manipulation by Abrasion
Over-brushing of fibers is the most recognized problem when it comes to visible seams. Installers don’t understand that aggressively abrading the turf fibers to hide seams will cause the seam to become different in color due to the reflection of light off of each fiber. Synthetic turf fibers are similar to plastic in many ways. They are flexible, strong and can withstand decades of seasons, but when the outer surface of the fiber is abraded it will receive light differently than other fibers that haven’t been manipulated. It will also become very visible when they are matted or bent flat.
When fibers are bent and lay flat, most will likely show a lighter color due to light reflection. When installing seams, body weight alone will reveal a visible seam in just a short period of time (see above, center picture). I see this a lot in overworked seams, usually caused by shoes, knees, and bags of infill mashing the fibers flat until they are no longer vertical. When this mashing consistently occurs, it creates matting. Matted fibers that stay this way may lose memory and be difficult to brush back to their original, vertical position.