With black hair, choose a dye that's only slightly lighter than your natural hair color unless you want to lift your hair via bleaching first. Select a dye that's a lighter shade than your natural color without being radically different, such as a dark brunette shade. Black hair has a lot of red and copper undertones. If you want an auburn hair color, select a reddish brown. This will bring out your natural coppery undertones to create your desired look. If you do not want an auburn shade, pick a color cooler than your natural hair tone. This will lighten your hair without giving it a coppery look. Before you begin the dyeing process, it's important to make sure you're safe. Dye can sting skin and stain clothing. Put on a pair of gloves and cover your shoulders with a towel to prevent stains. Use  your tinting bowl and brush, which should have come in your hair dye kit, to mix your dye and developer into a smooth, even mixture. In most cases, dye is mixed with developer in a one to one ratio, but read your instructions first. The precise ratio varies by the manufacturer. Part your hair down the middle of your head, making a part running from your forehead to the nape of your neck. The second parting should go across your head from ear to ear. Use hair ties or hair clips to keep your hair in four even sections. Apply dye starting with a section at the back of your head and then move forward. Working from the top of the section, use the brush that came with your kit to brush dye onto your hair in quarter- to half-inch (0.64- to 1.2-cm) sections. Keep adding dye to sections until the section is completely covered in dye. Then, move on to the next section. Usually, your dye should sit on for 45 minutes. However, this depends on the brand of dye, so refer to your package instructions. Let your dye sit in your hair for the required amount of time. After rinsing as much dye out as possible, shampoo and condition your hair as you usually do. Use the products that came with the kit, if applicable. When you're done,...

===
Write a summary of the previous text in Vietnamese:
Chọn thuốc nhuộm có gam màu nóng để tạo ra tông màu ánh đỏ. Chọn thuốc nhuộm có gam màu lạnh để tránh sắc độ đỏ. Bảo vệ bản thân khỏi ảnh hưởng của thuốc nhuộm. Pha thuốc nhuộm với thuốc trợ nhuộm. Chia tóc thành bốn phần. Lần lượt thoa thuốc nhuộm lên từng phần tóc. Để thuốc nhuộm trên tóc theo thời gian quy định. Dùng dầu gội và dầu xả.