Posted: Aug 17, 2017 9:31 pm
by GrahamH
romansh wrote:
GrahamH wrote:
romansh wrote:
GrahamH wrote:
Grey is a mix of R,G & B. I'm sure you know that. So blue-grey includes red photons. If there are lots more G & B photons than R from a pixel it isn't red.

OK did the photo of the strawberries have red pixels?

If not where did the bluey grey come from that David described?

I understand normally to get grey we need RBG photons; and darker it is less of them.


The pixels Are all mostly blue/green with a bit of red, so there are no 'red pixels' in the image but there are red photons.

OK where are the red photons coming from? Extraneous sources?

edit the light sources are not perfectly monochromatic?

From the 'blue-grey' pixels of course. You can't make grey without red photons.

BTW the light sources may not be perfectly monochromatic. For most TFT displays it will be white LEDs or electroluminescent lighting which are far from monochromatic shining though bandpass filters for RG & B that are tens of nm wide.