Counter-intuitive insight for shading (Lambert value scale)

edited November 3 in Drawing
This totally surprised me. I think we end up getting it right - but understanding what's happening here will totally change the way I observe and will speed up my ability to get the values right.
Unrelated to above except for the aspect that understanding helps with seeing: In my last painting I spent literally months trying to understand waves before I painted them. Now that I know what's happening I can see it in every wave at the beach.

Comments

  • edited November 3
    Fascinating, @Abstraction. I didn't know anything about Lambert's emission law. But now I know why I had trouble painting eggs in my early still lifes. I will certainly keep this in mind for when I next do a still life. And it will have eggs in it.  :)
    Abstraction
  • That is a good explanation of the lambert effect.  Thanks for posting.
  • Yes, thanks for posting @Abstraction, very interesting and helpful vid.

     :) 
  • Maths again!  Not my strong point.

    Talking of counter intuitive; but the 90 degree thing makes no sense to me.  Should the darkest not be closer to 180 degrees (but not as far as to get reflected light)?   Thant would make much more sense to me, somehow.
    If I have a vertical book on a bookshelf and the light is above, it is not as dark as it would be if the book were lying horizontal to the shelf a centimetre above the shelf, for instance.  That is what makes sense to me!

    The actual value changes look natural.    I have never used a scale, because they never looked to be of any use to me.   I always just drew what I saw.   Lambert's one looks much better.
  • @toujours they are assuming no ambient light. That’s why at 90 degrees it is 100% dark. 
    In the real world you have to adjust for ambient light.
    Abstraction
  • Don't worry about the maths - it's not needed at all.
    The main thing to consider is that when we are shifting from shade into light on a rounded object like a tree trunk or orange or face the shift is very rapid. When we are shifting from the bright side the shift is very gradual until we are close to the shadow.
    The reason I think 180 degrees feels more intuitive is that normally there is lots of reflected light around at 90 degrees. I think that also tells us something that if it is still quite light at 90 degrees it will be reflected light and therefore a shift in colour depending on where that light is coming from.
    tassieguy
  • @Abstraction -
    "The main thing to consider is that when we are shifting from shade into light on a rounded object like a tree trunk or orange or face the shift is very rapid. When we are shifting from the bright side the shift is very gradual until we are close to the shadow."

    This is the perfect cliff notes version of the video, and much more intelligible. Thanks. 

    AbstractionGTOtassieguy
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