To change the sky or not?

When shooting Daytime Long Exposure Photography you will find yourself many times at locations when the weather is not in your favour.  After you traveled for miles to reach a certain location and only have a short window of opportunity to get your shot, the building or bridge you want to shoot is there cooperating with you but the sky isn’t.  So what do you do? Should you afterwards in Photoshop change the sky to the gorgeous streaky one you shot just a few days before?

My take on it is yes, but as long as no one can tell and that it blends naturally with story of the image you want to convey.  Keep in mind that when shooting Daytime Long Exposures, an accentuated streaky sky creates drama, contrary, is the smooth calm ‘lightbox’ like look of a grey over casted day.  Remember that this is Fine Art, you are ‘creating’ an image rather than ‘capturing’ a moment (as in photojournalism).  This is my take on the matter but I open it to discussion.

Can you tell below in which image I changed the sky? (Design Museum #8 Above or Boat Below)

Southern Straits Boat Race #3, Vancouver BC, Long Exposure








Southern Straits Boat Race #3