It disappears more or less the wavelength of the light concerned. Any object seen through optics will be surrounded by coloured fringes, and if the object is s

It disappears more or less the wavelength of the light concerned. Any object seen through optics will be surrounded by coloured fringes, and if the object is small compared to the fringes -- then its all just rainbow nothingess. The size of the fringes depends on the instrument. But in a very high numerical-aperture microscope, it will be around about the wavelength of the light itself.