Wash your hands and put on a pair of gloves. Lay a lap cloth--plastic side down--on the tattoo workstation. Gather a disposable cup, four ink caps and a bottle of black ink.
Spread a thin, horizontal line of petroleum jelly onto the lap cloth with a disposable tongue depressor. The horizontal line should measure eight inches. Dispose of the tongue depressor in the trash.
Place the four ink caps onto the horizontal line of the petroleum jelly with an inch between each cap. Fill the disposable cup--your rinse cup--with distilled water. Place the rinse cup next to the ink caps on the lap cloth.
Fill the first ink cap with five percent black ink and 90 percent distilled water. Fill the second ink cap with 20 percent black ink and 80 percent distilled water. Fill the third ink cap with 30 percent black ink and 70 percent distilled water. Fill the fourth ink cap with half of black and half of distilled water. The lightest gray wash is in the first ink cap and the tones become darker when moving to the next ink cap.
Dip the needle into the rinse cup in between each shade of gray while tattooing to avoid mixing dark tones with the light. Dispose of the lap cloth, gloves, ink caps and rinse cap into a biohazard trash receptacle after tattooing. Deposit the needle into a sharps container.