The photo on the left is of a leaf which has not begun to change color.  Notice that the leaf veins are yellowish.

The photo on the right is one of my study leaves.  Between Sept. 29th and Oct. 1st, the veins started turning red.

All of the leaves that have fallen off my Silver maple so far have been yellow, not red.  I wondered, will my study leaves turn red or do the yellow leaves have red veins?  I searched my yard for fallen leaves.  I looked at dozens of fallen leaves and discovered that there are two patterns.  All of the leaves seem to be turning mostly yellow.  Some have a light yellow mid-vein with the other veins remaining green.  Others have mostly red veins with more green remaining on the other parts of the leaf.  Now I wonder why there are two color pattens on the leaves!

The photo above is of two leaves from my maple trees.  See how the left leaf has a yellow mid-vein and all of the other veins are green?  The leaf on the right has red veins.

I brought two leaves inside to take a better photo.  It is very interesting to me that the green on the left leaf is on the veins and the green on the right leaf is not.  I might have to find an expert to explain this to me!