When we paint, we communicate through a rich visual language. Images speak, yes, but how we present them influences what they say. In their raw form each is in a context of a unique light and/or shadow. We can paint the image in strong light, in weak light, in strong shadow, in weak shadow. We can make the image light and it's surroundings dark, make it dark with it's surroundings light, make it include both lights and darks in a variety of surroundings. The same image repeated in a variety of lighting will communicate
differently. The element of our language making this happen we call "value". You know that. But had you considered it as a part of your language's vocabulary?
Our language's vocabulary includes value, hue, intensity, temperature, shape, size direction, lineand texture. These are the elements with which we "speak" as painters.