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Thread: How shadow works?

  1. #1
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    Question How shadow works?

    I have been learning painting and digital art for around 5 years, and I can create artworks like this. When I do life paintings or Alla Prima I just put down the colours I see (with a bit of the colour theory). But when it comes to original art, I need some scientific rules for colouring.

    There is one basic colour theory bothers me all the time: Should form shadow be more saturated than the light tone? (single colourless light source, no environmental colour etc.) I know pretty well how light bounces and how colour mixes, but I am not sure if light takes away saturation of gives saturation.

    The tutorial I found here says shadow should be desaturated since not much light reaches there; However another tutorial here says shadows are usually more saturated.

    Both theory/methods work quite well in real life, such as the Korean artist Hyung Tae Kim's work (colour gets less saturated when it gets darker)


    or this, colour gets more saturated in dark tones.


    They are exactly the opposite theory but both work well. What do you think about this? It may all depends on the situation, but when you paint which theory you prefer?

  2. #2
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    I've followed your work and think you're a brilliant artist with great talent. Congratulations.

    To simplify matters, I would summarize as follows:
    The complementary of a secondary color is the primary color that wasn't used to make it. So the complementary color of green is red, of orange is blue, and of purple is yellow. When placed next to each other, complementary colors make each other appear brighter, more intense. Most shadows are not merely black, but contain lots of colours, from crimsons, reds, greens to purples, if there are reflections from a neighbouring object. Careful observation and accurate colour mixing is the key to capturing convincing shadows. The shadow of an object will also contain its complementary color, for example the shadow of a green apple will contain some red. Introducing the objectís complimentary colour is a good way of darkening its colour.

    It is clear that when it comes to light, shadows, color grading, general composition of the painting, everything is very complex. For example, the color temperature, hot or cold, which is not an intrinsic characteristic of color is no longer taken into account by some modern streams. Thus, one of the best ways of painting is to paint what you see. Very cool that you raise this point. Controversial, and The links are very cool.

  3. #3
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    Whisper, see this link discussing the issue.

    http://www.conceptart.org/forums/sho...d.php?t=156193


  4. #4
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    Quote Originally Posted by Lima View Post
    I've followed your work and think you're a brilliant artist with great talent. Congratulations.

    To simplify matters, I would summarize as follows:
    The complementary of a secondary color is the primary color that wasn't used to make it. So the complementary color of green is red, of orange is blue, and of purple is yellow. When placed next to each other, complementary colors make each other appear brighter, more intense. Most shadows are not merely black, but contain lots of colours, from crimsons, reds, greens to purples, if there are reflections from a neighbouring object. Careful observation and accurate colour mixing is the key to capturing convincing shadows. The shadow of an object will also contain its complementary color, for example the shadow of a green apple will contain some red. Introducing the objectís complimentary colour is a good way of darkening its colour.

    It is clear that when it comes to light, shadows, color grading, general composition of the painting, everything is very complex. For example, the color temperature, hot or cold, which is not an intrinsic characteristic of color is no longer taken into account by some modern streams. Thus, one of the best ways of painting is to paint what you see. Very cool that you raise this point. Controversial, and The links are very cool.
    Hi, thank you for your reply. I fully understand the use of complimentary colours. As you might aware, the mix of two complimentary colours would be gray. So if here's an red apple and its shadow contains a bit of green- does it mean the shadow would therefore look more gray-ish? (As I said, I am not considering any of the environmental colour or light source)

    I find gray shadows quite cool because it seems gray is a good contrast of everything.

  5. #5
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    Quote Originally Posted by Lima View Post
    Whisper, see this link discussing the issue.

    http://www.conceptart.org/forums/sho...d.php?t=156193

    Yeah thank you for the link!

    In fact there are many people asking the same question. But most people end up with answering how a neighbour (environmental) colour would affect the shadow, like how a red wallpaper would cause a warmer shadow to a green pepper. Or how our eye see more complimentary colour in shadow to balance our vision... And at the end 'it always depends'.

    However the real question is, without any environmental light/colour, under a neutral light, matt surface, no reflection (perfect scenario), would shadow be less saturated than the light because it receives less 'light wave' (therefore less reflection into our eyes)?

    The 'most saturated core shadow' is another popular theory. Some people think the truth lies in between: both strong light and lack of light would wash colour away.

    I personally think shadow should be desaturated in that 'perfect scenario'. But in real life colour always bounces back (like between your neck and chin) which makes the shadow seem more saturated.

  6. #6
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    On a translucent or semi-translucent surface (human skin) the shadows contain transmitted light that travels through the surface. This will tend to intensify the color in the area before it falls off into less saturated shadow. In 3D computer graphics this phenomenon is described as 'sub-surface scattering.' If a surface is entirely opaque (a painted house) then this effect is nearly absent.

    Reflected light from other surfaces facing the shadow side of an object can create the appearance of translucence under the right circumstances but usually imparts some of it's own color to the shadow surface.
    Last edited by Fashmir; 03-19-2011 at 05:35 AM.
    Be well,

    "Teach, Learn, Thrive"~DM


  7. #7
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    a simple example

    Right I think what I said might be a bit misleading.

    As I said I am not talking about ANY light source colour or colour reflecting/bouncing etc. There is just this simple situation:



    And which one do you think is right? And why?

  8. #8
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    Whisper, briggsy's links from concept art are fantastic and modern. They discuss this question of color and saturation, light...

    What was the original color of the balls before the incidence of light?
    What kind of light did you used?
    What was the source of light?
    Photoshop?


    Watch this short movie I made:


    http://www.youtube.com/watch?v=gyLTYT_kE_g

    Observe the movements of the sampler, as well as the movement of the small circle indicator on the picker.

    You can see that the in the center of the balls, the colors are similar.

    In the right sphere, intensity oscillates vertically, showing a lower saturation in the south periphery. .

    In the left sphere, there is no change in intensity, but rather of value, where one observes the shading of the color.

    I do not know, I'm confused by this situation. I would like you to teach us more about this.

    A bit more about shadows:

    "Not all shadows are equal. There are in fact two very different kinds of shadows that occur in any subject -- cast shadows and form shadows. Identifying these and approaching them differently, rather than just painting a generic Ďshadowí, will enhance any painting. So what is the difference between a cast shadow and a form shadow?

    What is a Cast Shadow?

    A cast shadow is what we generally think of as a shadow. Itís a shadow created by something blocking the light source. For example, the shadow of a tree, created by the sunlight, that falls on the ground. Or the shadow on a tabletop from an apple sitting on it. Or the shadow of a nose falling on a cheek.

    A cast shadow is the darker type of shadow, because itís created by the light source being blocked. It has quite a sharp or more definite edge to it. But itís important to remember that a cast shadow isn't a solid thing thatís the same throughout: the further a cast shadow is from the object thatís creating it, the lighter it gets and the softer or less defined its edge becomes.


    What is a Form Shadow?

    A form shadow is the shadow on a subject on the side that is not directly facing the light source. Or what you might think of as the parts of the subject Ďin the shadowí because they donít have direct light on them but also donít have a cast shadow falling on them. I've sometimes heard it referred to as an area with a "lack of light", which I think makes a nice distinction from what we generally visualize as "shadow".

    A form shadow has a softer or less defined edge to it than a cast shadow. It is lighter than a cast shadow because itís created by light not reaching around the object rather than a shadow being thrown by the object where it directly blocks the light source. Form shadows are subtle shadows, essential for making a subject appear three dimensional rather than flat. The changes in forms shadows requires very careful observation -- squinting at the subject often help you see them more clearly. If most of the subject is in direct light, there will be very little form shadow in it.


    Think, for example, of a vase on a table, where the light source is at about two oíclock. The top edge of the vase is in the direct light and there will be a cast shadow made by the vase on the table. The parts of the vase not in direct light are in form shadow."


    whisper this is a nice discussion, at least we can study it a bit.

  9. #9
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    Quote Originally Posted by Lima View Post
    Whisper, briggsy's links from concept art are fantastic and modern. They discuss this question of color and saturation, light...

    What was the original color of the balls before the incidence of light?
    What kind of light did you used?
    What was the source of light?
    Photoshop?


    Watch this short movie I made:


    http://www.youtube.com/watch?v=gyLTYT_kE_g

    Observe the movements of the sampler, as well as the movement of the small circle indicator on the picker.

    You can see that the in the center of the balls, the colors are similar.

    In the right sphere, intensity oscillates vertically, showing a lower saturation in the south periphery. .

    In the left sphere, there is no change in intensity, but rather of value, where one observes the shading of the color.

    I do not know, I'm confused by this situation. I would like you to teach us more about this.

    A bit more about shadows:

    "Not all shadows are equal. There are in fact two very different kinds of shadows that occur in any subject -- cast shadows and form shadows. Identifying these and approaching them differently, rather than just painting a generic Ďshadowí, will enhance any painting. So what is the difference between a cast shadow and a form shadow?

    What is a Cast Shadow?

    A cast shadow is what we generally think of as a shadow. Itís a shadow created by something blocking the light source. For example, the shadow of a tree, created by the sunlight, that falls on the ground. Or the shadow on a tabletop from an apple sitting on it. Or the shadow of a nose falling on a cheek.

    A cast shadow is the darker type of shadow, because itís created by the light source being blocked. It has quite a sharp or more definite edge to it. But itís important to remember that a cast shadow isn't a solid thing thatís the same throughout: the further a cast shadow is from the object thatís creating it, the lighter it gets and the softer or less defined its edge becomes.


    What is a Form Shadow?

    A form shadow is the shadow on a subject on the side that is not directly facing the light source. Or what you might think of as the parts of the subject Ďin the shadowí because they donít have direct light on them but also donít have a cast shadow falling on them. I've sometimes heard it referred to as an area with a "lack of light", which I think makes a nice distinction from what we generally visualize as "shadow".

    A form shadow has a softer or less defined edge to it than a cast shadow. It is lighter than a cast shadow because itís created by light not reaching around the object rather than a shadow being thrown by the object where it directly blocks the light source. Form shadows are subtle shadows, essential for making a subject appear three dimensional rather than flat. The changes in forms shadows requires very careful observation -- squinting at the subject often help you see them more clearly. If most of the subject is in direct light, there will be very little form shadow in it.


    Think, for example, of a vase on a table, where the light source is at about two oíclock. The top edge of the vase is in the direct light and there will be a cast shadow made by the vase on the table. The parts of the vase not in direct light are in form shadow."


    whisper this is a nice discussion, at least we can study it a bit.
    Right, let's just talk about what it is going to happen to 2D. See the image I attached: the two pieces of paper start with the same colour and end up with the same darkness. The only difference is the satuation in the end. The light is colourless and neutral strong; The environment is neither dark nor bright. What would happen?
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	flat sample.jpg 
Views:	128 
Size:	80.0 KB 
ID:	53781  

  10. #10
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    In reality, I think, it would depend on the distance involved. Think about two buildings in perspective. The more saturated of the two images, would read better, as the object in the foreground, while the less saturated image, would best be understood as an object further away. This would be explained by the effects of our atmosphere diffusing the light and colors that make it to our eye.
    Nothing is easy to the unwilling.

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