A photon is a concentrated packet of the EMF that was formed, as were all particles, in the early moments of the BB during extreme conditions of heat and pressure and turbulence. The particles can only be formed during such extremes.
As the U expanded and cooled the particles stabilized.
The retinas of our eyes are analogue receptors and not digital. They therefore cannot detect photons.
The response curves are standard analogue bell curves as in standard analogue filter design.
Our retinas have red, green and blue receptors.
We only see a limited range of the electromagnetic spectrum.
As analogue receptors they detect waves in the EMF.
These waves are formed by the passage of photons which create a shock wave front.
The more photons following each other the greater the frequency of wave fronts and the higher the energy per second.
The energy of a single photon is 6.62x 10(-34) Joules or watt/second.
Therefore it has mass.
In the two slit experiment. The photon doesn't have to go through two slots. Only the shock waves do, to cause interference patterns.
So there is no duality to light.
A photon is a particle, and a wave is a disturbance in the field caused by the passage of the photon. These are separate phenomena.