How Does Tattoo Ink Work, and Why Does it Fade?
In the Skin
The epidermis, the dermis, and the subcutaneous fat layer. The Dermis is connective tissue, it contains the blood vessels, sweat glands, hair follicles ect.
Where does the ink go?:
Tattoo needles go through the epidermis and into the dermis layer. The body reacts to tattoo ink as a foreign invader and white blood cells rush to the area which is where the swelling and scabbing comes from.
Tattoo needles:
Tattoo needles use physics to deposit ink into your skin!Tattoo needles are made up of a bundle of multiple small needles. In shaders there are more than in liners and they are arranged differently. Ink is held between the needles with surface tension and something called Capillary action, very similarly to water being held between 2 panes of glass. Once the ink is held in place and the needle punctures the skin the ink in drawn into the wound. The surface tension works with adhesive forces to create a flowing effect from the ink in the needle down into the skin until it is deposited into the dermis.
The Science
When tattoo ink is injected into the second layer of skin, the dermis, it creates a wound. The wound initiates the body’s immune system. Macrophages are the first line of defense in the immune system and they rush to the area. Macrophages job when there is a wound or infection is to rush to the area, identify foreign material, and engulf it. This method works great for bacteria, the macrophage ingests the bacteria and uses an acid to digest it and dispose of the foreign material (Wilhelm 2018). However tattoo ink is not affected by this acid in the same way; the macrophages can’t digest the tattoo ink so they just hold it in place (Wilhelm 2018). Wilhelm uses the example of the macrophages being vacuum cleaners, and when they engulf tattoo ink it’s like the vacuum bag is full and they can’t empty it. This is why the ink stays in place and creates the image in your skin.
Cells, including macrophages, don’t live forever. Our bodies are constantly generating cells to replace the existing cells as they die. When these macrophages holding ink die, they release the ink they were holding. New macrophages are quick to rush to the scene and ingest the once again foreign material, this is what makes tattoos permanent. However, this releasing and encapsulating of the ink allows a little spreading or ‘bleeding’ of the ink. Over many cell cycles of releasing and engulfing the ink travels and this is partly why we see tattoos fading over time. This immune response is also responsible for all that redness, swelling, and scabbing that we get while healing the tattoo!
So What’s With the Fading
There are lots of factors that contribute to how a tattoo heals and ages, one that we can’t control is this immune response and the cell cycle. As well as the fact that some areas of the body are more prone to fading than others. Fingers, armpits, and feet for example are areas that get more wear and tear and could fade faster than some other areas. You can also experience fading during the healing process with improper aftercare such as over moisturizing. Picking at or peeling off scabs while that tattoo is healing could also result in some patchy healing or fading appearance. Anything that could negatively affect your skin will ultimately affect your tattoo as well. Too much exposure to sun or sun burns can play a factor in fading, as it can harm your skin over time as well.
Once a tattoo is fully healed it means that the top layer of your skin, the epidermis, is healed and there is no ink left in that top layer. The ink is sitting in the second layer, the dermis, and a new ink-free layer of the epidermis is covering the tattoo.
In the end fading is unavoidable because your skin is an organ subject to its own aging and wear and tear but there are ways to take care of your skin and tattoo to help keep everything healthy and vibrant. Such as using sunscreen, being diligent about doing proper aftercare, and generally just good hygiene will help you with a happy heal and the best results.
Sources
- “Here’s What You Need To Know About Tattoo Fading.” Tattoo Moisturiser, 9 Mar. 2020, www.tattoomoisturiser.co.uk/tattoo-fading/.
- “Layer of Your Skin.” Healthline, 5 Jan. 2018, www.healthline.com/health/layers-of-skin#The-takeaway.
- “NCI Dictionary of Cancer Terms.” National Cancer Institute, www.cancer.gov/publications/dictionaries/cancer-terms/def/dermis.
- “Skin Deep Science – How Do Tattoos Work?” Australia’s Science Channel, 12 Sept. 2017, australiascience.tv/skin-deep-science-how-do-tattoos-work/.
- Wilhelm, Menaka. “Tattoo You: Immune System Cells Help Keep Ink In Its Place.” NPR, NPR, 8 Mar. 2018, www.npr.org/sections/health-shots/2018/03/08/591315450/tattoo-you-immune-system-cells-help-keep-ink-in-its-place.
