Colour is a way that we describe an object based on the way that it reflects or emits light.
Your eye can see different colours because the retina is sensitive to different wavelengths of light, which hit objects and are reflected from their surfaces.
The colours we see, such as the three primary colours, red, blue, and yellow, depend on how these light waves are reflected.
In general color is caused by the absorption of certain wavelengths of light by a substance.
Humans are what is called "trichromats," meaning our retinas have three different kinds of cells that can receive color. Those cells are called cones. Rods work more with dimmer light and peripheral vision.
We will all see colours differently - and so there is no wrong when selecting the colour bottles. It is your perception that is true for you.
Colour blind or even blind people have no filters like we have so a colour session can be very powerful for them.
This is also why - choosing 'blind' can be more effective because we get out of the way of our brain and into our higher intuitive self and go with our feeling - our heart and gut.