Weathering a CN N scale boxcar

[Herc Driver]

Here's that shot I mentioned showing the subtle shading difference between chalking with white and yellow/white. (These were some of the first cars I made a serious attempt at weathering with chalk.) I bought three identical cars, the untouched car is on the right. The middle car is weathered with white chalk only, and the car on the left is weathered with a mixture of yellow and white chalk. The picture quality is prbably not good enough to tell the subtle shading difference...but you can see a slight difference.