This weekend was spent backdrop painting on the lower deck.  I am using a pale blue that won't distract from the foreground scenery.  I then blended the blue into white near the horizon line to simulate the effects of atmospheric scattering seen in real skies.  

I didn't want to feather the sky into the horizon using spray paint so I dry brushed using a wide brush and white acrylic paint.   The banks of distant cirrus clouds are also created by dry brushing.   A flat wide brush is dipped in white acrylic and most of the paint is wiped off on a rag.   Then, simply drag the brush horizontally back and forth. 

Working the paint in a circular scrubbing motion and then tapping the brush in irregular patterns helps to add light airy elements to the clouds.   The subtle shading of clouds and haze may not come across too well in photographs but in person it looks very pleasing.

I should add I am not an experienced backdrop painter.  I merely applied the dry brushing techniques I use to weather freight cars.   Anyone who wants to add clouds but is not sure of their skill might want consider cirrus over fluffy cumulus.  Its a lot easier to get a good result.

The bridge is a mockup.  Locomotive is one of two 'almost-finished' detailed, painted and weathered BC Rail SD40-2s