Light is different at different times of the day:                         Back
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                               Some times it's obvious but not always. in the photo's below it's painfully obvious.
 

   The difference in light is clearly visible here but is not so obvious at other times.  Vincent Van Gogh found the light in Arles, to be much to his liking. Why because it was usually cloudy. Without direct sunlight colors are more vibrant & there are less, distracting shadows.

   Sometimes in photography we want the same. We even strive to obtain it, we'll use fill flash or reflectors to light areas that are in shadow. Film is very, very light sensitive & the differences your eyes compensate for become extremely noticeable once we have our film developed.
 

Left: around noon on a sunny day, colors washed out & shadows under plant. Poor quality photograph.         

Right: mid-afternoon brighter colors more contrast. A better photo