>>3821478>so in OP's pic the white part of the dress in light looks warm compared to the blue shadow.
Yes. You can also see how most of the shadows on the dress are blue because they reflect the sky, but the undersides of her arms and the bottom of the dress, areas that are in shadow, are warm because they are illuminated by the reflected light from the grass.>given that sunlight is cool light, the blue shadow on her dress is technically warmer than the white light?
No. Sunlight is cool in the sense that its hue lies in the cool half of the color wheel, slightly bluer than pure green if you want to be precise. And, as I already said, the sun emits a whole spectrum of wavelengths, as you can see here >>3821308
, that's why it looks white instead of green. The shadows, those parts that face the sky, are cooler than the white light of the sun, because the sky is cooler compared to sunlight. So, while sunlight is cool, the sky is still cooler, that's why you get cool shadows. They look cool and they are technically cooler, as you can see for yourself if you use the color picker.
Light temperature, or effective temperature is the literal temperature that a "black body" would need to have, to emit light with the maximum at a given wavelength (hue). Black body is a model, an idealization that approximates how real bodies emit light. Like any temperature, effective temperature can be measured, and in physics temperature is measured in kelvins (K). Red color has the lowest temperature and blue color is the hottest. Color warmth on the other hand is just a phenomenon of human psychology, we associate some colors (like orange) with warmth, and others (like blue) with cold, and it is kinda inverted compared to the effective temperatures.