The Web safe color will not be retained through the filtering process, and dithering or color shifts are less noticeable in a textured graphic. Gray taupes seem to be less prone to this shift. The line in the center of the image appears when Offset filter is applied. There is also a slight vertical seam, but we will repair the horizontal one first. Selected area moving to cover light line.
Arrows represent direction of move as well as the approximate final position for selected area.
Pasted copy is moved to cover the vertical seam. It will come to rest, aligned to the horizontal pattern, just below the edge top edge. Never make adjustments at the edge of the tile as you may lose the seamless effect. Create a texture Set taupe as your foreground color and black as the background color. Set Size 1, Contrast 0, Pattern Type Line.