In answer to the question that auras don’t exist, and that you are just seeing an after image from staring too hard, consider the differences between an after image and a real, perceived image. The way the aura builds up is totally unlike the way an after image appears. If you shift focus slightly, or blink while an aura is building up, it disappears instantly. An after image does not.
The aura reflects our health, mental activity and emotional state. It also shows disease - often long before the onset of symptoms, since auric energies are affected by our surroundings and life style.
Diseases cause auric disturbances. These disturbances are common, but vary in size, shape, color, density. Disturbances can be in one layer or cross multiple layers. Disturbances can be secondary - associated with other disturbances in other layers such that a bulge mal-forms in adjacent layer(s).
The goal is to be able to spot disturbances and determine what they are affecting. Disturbance can be right over a physical organ. Unless masked by medication, the stronger and deeper the color, the more enrenched the disturbance is. The layer containing the disturbance corresponds to a chakra which corresponds to a body part.
Street drugs alter the aura by warping and twisting it. Holes, fractures, grooves and growths occur through multiple layers of the aura, resulting in instability. Use extreme caution: you are working with something very unpredictable in nature.
Perhaps the most actively changing layer is the one closest to the skin - the etheric aura. It is the grey or blue fuzz clinging to the body and no more than half an inch wide. During waking hours, it is present in its contracted state. During sleep the etheric body expands opening and absorbing and storing cosmic energy. On waking it contracts again. So you really do get rejuvenated from a nap or sleep.
Commonly, books and interactive programs class people and assign them a by the basic hue, or the dominant color, of their aura. This can be misleading as the aura is complex and changeable.
The aura is sensitive to color reacting to the colors of clothing and to that of its surroundings. This accounts for our natural likes and dislikes when it comes to choosing the colors that surround us.
The effect of color on the emotions is well known and widely used in wellness facilities to calm agitated people and put them at ease. Pink is the most frequently used color for this as it is the emotional color of love and happiness.
Disease shows up in the aura in many different ways, weeks or months before any physical symptoms.
The onset of death is quite striking. As the physical body is not required in the after life, it’s matrix, the aura, begins to disintegrate. It can become quite frail and gauzy and often erratic with colored sparks shooting out – like a mini fireworks display.