This is usually caused by three reasons. One is because the skin itself is not completely white, and it is basically yellowish or reddish, so the recovered color is covered under the skin and the black tattoos seen by the eyes (especially totems) Type) will be affected by the background color of the skin and will form a color deviation. The second reason is that the tattooist pierced the skin too deeply during the tattoo process, and the color material and part of the blood of the capillaries combined to cause the color to appear blue or green. The color used by the third tattoo artist is not pure black color. Without this foundation, there is no way to restore a better black if the technical methods are in place.
