Terry, The 665nm conversion allows a little of the color spectrum through. (Our regular cameras have a hot mirror on the sensor that blocks IR and lets all colors through as we see them.) The colors that come through on my 665nm IR conversion, are red in the sky and cyan in the foliage (sometimes the red in the sky is more golden, like it is in this photo.) To make a blue sky, I go into Photoshop and flip the red and blue channels by selecting the red channel and setting it to zero and the blue to 100%. Then selecting the blue channel and setting it to zero and the red channel to 100%. A hue/saturation adjustment layer is usually necessary to get the sky color just right. That is why it is called false color, because the color as the camera sees it is not the color you see with your eye. You might notice that the camera sees a lot of extra detail, that is why deep IR photography is used for forensics.