 Colour in flowers, pot and leaves in white light.  Total black box room  Red lamp is lit.

 Objects with red pigment will appear red when lit with a red lamp.

We developed this theory BECAUSE :  Items containing red pigment absorbe all colours but red.

On the basis of:  Adsoption and reflection laws.

 Probably there is some red pigment in all objects and will appear not all black

We believe our theory is a valid explanation....UNLESS:  The objecets are light with another colour lamp.