Home Forums The Learning Center Color Theory and Mixing Is Jack Faragasso wrong about shadow behavior in colored light?

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  • #476424
    SquishyFishy
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        Hi,
        I have Jack Faragasso’s “Student’s guide to painting”, which follow the Frank Reilly school of art methods.

        I came across the attached diagram and it struck me as not having a physical explanation; aka wrong. This diagram is meant to show what color a cast shadow on a colored surface should be, if cast by a colored light source. (or so I understood)

        So a cast shadow is when light is BLOCKED by an object. It would be perfectly dark if not for the AMBIENT light falling on it and making it a bit lighter.

        The shadow should be the color of this AMBIENT light falling on the background color of the surface onto which it is cast. The color of incident light shouldn’t matter at all.

        Most importantly, there is nothing that says the ambient light should be the complement of the incident one.
        I can use a red lamp to cast the shadow of a black object onto a white background with ambient purple light in the room, the cast shadow will be a dark purple, no? I pick the lamp colors how i like!

        Now, things get more complicated when you are casting a colored shadow onto a colored surface, when you have the colored incident light bleeding over the edges of the object, and when the object itself is strongly colored and reflects its surface color light onto the shadow, too. But, let’s handle just the 2 colored lamps.

        How do I redraw this diagram to make sense? I definitely do love the structured approach of the Reilly school.

        #863019
        lambentLogic
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            Is the assumption that the ‘ambient’ light source is largely white, but part of that ‘white’ is the directed colored light? I found this video looking into it, and it certainly appears that when all lights are turned on, blocking the green light source will make a magenta shadow, but if only two of them are it will indeed be the other light instead. I’ve also heard of leaning towards blue light in ambient shadows when you are outdoors and ‘ambient light’ is from a blue sky.

            Anecdotally, I’ve certainly looked into a room with a bunch of green lights and seen a bunch of magenta shadows.

            C&C welcome
            Etsy: FineArtAnn

            #862991
            WFMartin
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                The answer to what color a cast shadow should be is no further away from you than a relatively simple, straightforward, visual test. You don’t need to make your decision based upon what someone tells you the color of the cast shadow should be–just look.

                Let me offer two examples. My wife and I used to walk early in the morning when street lights were still on. Because of these orangey, yellowish street lights being the illumination, the cast shadows on a neutral gray sidewalk were a definite Blue, biased a bit toward Cyan. Both of these are complements to Yellow, or Orange colors, which is the color of the illuminating streetlight.

                At my workplace, we had a computer room that only had Green light as its illumination. All the shadows that were cast by computer components, such as the mouse, the computer stack, the monitor, upon the neutral table top were a most definite “Pink”, or “Magenta”–the complement of Green. Keep in mind that when a room is only illuminated with Green light, absolutely NO other color exists in that room, but Green. For that reason, we cannot assess this “Pink” appearance to reflected light, ambient light, or extraneous light sources, or any kind. It is an optical illusion!

                I’ve had another experience in which a Blue-ish light resulted in an actual “Yellow” shadow being cast.

                One does not need to accept the words, or opinions of others regarding the appropriate colors to paint cast shadows, including MINE–all you need to do it to observe for yourself.

                For me, the basic concept of cast shadow colors is: The color of the cast shadow should be painted in the complementary color to that of the LIGHT SOURCE.

                Of course there are numerous OTHER influences, such as extra light sources, and colors of nearby objects reflecting their colors upon the surface, each of which can contribute to the color of the cast shadow, but the primary factor is that an optical illusion is created by the color of the light source creating cast shadows that are its exact complement. Because it is an optical illusion, it won’t be seen on a photo of the scene, simply because it truly doesn’t exist. Yet, it most surely should be represented in your painting, because that’s the way a viewer would view the scene (with all its optical illusions).:)

                But, don’t take my word for it; just set up a couple of test “scenes” in which you can control the color of the light source, and then merely observe what colors you witness emanating from the cast shadows.

                My “recipe” for painting a believable cast shadow is to do the following: First I mix up a darker version of the color of the surface upon which the shadow is being cast. Then, I mix in just a bit of the complementary color to that of the color of the light source. Hasn’t failed me yet.:)

                wfmartin. My Blog "Creative Realism"...
                https://williamfmartin.blogspot.com

                #863020
                SquishyFishy
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                    The answer to what color a cast shadow should be is no further away from you than a relatively simple, straightforward, visual test. You don’t need to make your decision based upon what someone tells you the color of the cast shadow should be–just look.

                    Let me offer two examples. My wife and I used to walk early in the morning when street lights were still on. Because of these orangey, yellowish street lights being the illumination, the cast shadows on a neutral gray sidewalk were a definite Blue, biased a bit toward Cyan. Both of these are complements to Yellow, or Orange colors, which is the color of the illuminating streetlight.

                    At my workplace, we had a computer room that only had Green light as its illumination. All the shadows that were cast by computer components, such as the mouse, the computer stack, the monitor, upon the neutral table top were a most definite “Pink”, or “Magenta”–the complement of Green. Keep in mind that when a room is only illuminated with Green light, absolutely NO other color exists in that room, but Green. For that reason, we cannot assess this “Pink” appearance to reflected light, ambient light, or extraneous light sources, or any kind. It is an optical illusion!

                    I’ve had another experience in which a Blue-ish light resulted in an actual “Yellow” shadow being cast.

                    One does not need to accept the words, or opinions of others regarding the appropriate colors to paint cast shadows, including MINE–all you need to do it to observe for yourself.

                    For me, the basic concept of cast shadow colors is: The color of the cast shadow should be painted in the complementary color to that of the LIGHT SOURCE.

                    Thanks for the detailed response. It made me think.

                    I found these articles and am inclined to believe them, especially James Gurney:
                    http://gurneyjourney.blogspot.com/2010/10/chromatic-shadows-part-2.html

                    http://monkeylogic.us/blog/warm-light-doesnt-have-cool-shadows/

                    I think we just happen to come across a lot of scenarios where by chance the incident light happens to be a complimentary to the ambient.

                    I don’t see how it would be an optical illusion, either. If it were so, then any time we have 2 strongly surface colored objects next to each other, they would cast complimentary colored shadows onto each other. Reflected surface light is colored light.

                    Now, the question is, do I just mix equal percentages of paint representing light color into the shadow colors?

                    #862992
                    WFMartin
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                        The degree of complementary color you wish to mix into the already-mixed dark color of the cast shadow is rather up to you as an artist, I feel.

                        The impressionists seem to have been some of the first ones to have taken notice of the colors of cast shadows, and their work usually reflected that. Their “philosophy” seems to have been, “Warm light/ cool shadows, and cool light/ warm shadows”, which just about covers the noticeable effect that I mentioned.

                        However, the impressionists usually exaggerated the effect, including much more of the complementary color into their mixture than would seem appropriate for acceptable “realism”.

                        Realize that often when you mix the complementary color into your cast shadow for the purpose of creating a realistic cast shadow, the complementary color will often do nothing more than slightly “tint” the existing color, or it may even turn it neutral, if the color of the cast shadow happens to be closer to the color of the light source. However, in either of these cases, adding the complement to that of the light source is truly performing exactly as should be expected, making the “slight tint”, or even the “neutral” quite appropriate for the cast shadow.

                        However, I often “cheat” just a tad, and I will add just a bit more of the complementary color to that of the light source, just as a slight exaggeration, but not NEARLY as much as the impressionists did, that is……unless I am creating my own version in an impressionistic style. Then, I tend to exaggerate the color more.

                        Yeah, Gurney pretty well said it. However, a great deal of HIS cast shadow color is caused by ambient light (of the opposing light source), so very little of the color witnessed in his demonstrations are the result of PURE optical illusion. Some is, yes, but most of it is not.

                        To show just how convinced I am of this optical illusion, let me offer one more example that I witnessed. My wife and I were sitting in a Chinese restaurant, eating. I noticed that my hand, and fork were casting what seemed to be a “yellow (Ochre”) shadow across my white plate. Without looking anywhere but at my plate, I told my wife, “There HAS to be a Blue light in this restaurant!” Sure enough, when I looked directly up, I saw that our table had a blue bulb in a conical shaped shade, hanging directly above our plates. And, in this case, there was no, apparent other “Yellow” light source that would cause the effect.

                        Keep in mind that in a room that is only illuminated with Green light, there is absolutely NO other, ambient, reflected, light at all. You only see “Green” in terms of color. The fact that one can even witness the “effect” of Magenta, or “pink” in a room such as that very controlled situation, it HAS to be caused by something else (such as an optical illusion), merely because there no other color of light to cause the effect.

                        wfmartin. My Blog "Creative Realism"...
                        https://williamfmartin.blogspot.com

                        #863007
                        Ellis Ammons
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                            color picker is your friend.

                            just punch a small hole with a pencil in a peice of paper and hold that up so you can only see the shadow or whatever. then u can check your paint by dapping it by the hole and see if its same. u can get a app on your phone 2.

                            Imo there is no such thing as a casted shadow color. Shadow is something blocking light rays from falling on an object. The object gets its color from light rays bouncing off other objects and then striking it. The actual color of the object cannot be calculated by some magic all encompassing algorithm someone has the the answer for 5.99.

                            Check out my work in the acrylics Hall of Fame Camellia WIP
                            oil and acrylic paintings..

                            #863005
                            davidbriggs
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                                I don’t see how it would be an optical illusion, either.

                                Our visual system partly adapts to the colour of the main illumination, and this adaptation that makes the main illumination shift to appear less colourful makes physically neutral illumination in the shadow areas shift in the same direction to appear the complementary hue. The phenomenon of “coloured shadows” has been described many times since the 18th century, but as Bill says the best thing to do is to set up two light sources, one of them coloured, and observe for yourself.

                                Colour Online (hundreds of links on colour): https://sites.google.com/site/djcbriggs/colour-online
                                The Dimensions of Colour: www.huevaluechroma.com
                                Colour Society of Australia: www.coloursociety.org.au

                                #863008
                                Ellis Ammons
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                                    Id say leave the illusion out and put the real color in. That way if you make the painting real enough it might have the same effect on the viewer and add to the realism.

                                    Optical illusions come and go. Ive found it best to avoid them. You can get stuck in a painting real quick when your eyes start playing tricks on you.

                                    Check out my work in the acrylics Hall of Fame Camellia WIP
                                    oil and acrylic paintings..

                                    #862998
                                    oddman99
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                                        Bill Martin and David Briggs posts are absolutely correct. Our eyes (and, therefore, brain) perceive the complement of the incident light surrounding the shadow. Call it an optical illusion or neurological phenomenon, it’s how we see. As Bill points out, this was well recognized by the Impressionists.

                                        Using an optical checker is not how we usually see a scene. It eliminates the effect of the light surrounding the shadow has in stimulating our visual perception.

                                        #863021
                                        SquishyFishy
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                                            I know I can just “observe”, but the first article with the simulated colored spotlights seems correct to me. I’m inclined to go and ignore any optical illusion effects.

                                            It would be nice to have some kind of rule-based model though, at least to know what to look for when observing.
                                            I’m sure when working with just value studies, most people already simplify the number of light sources or the distance, for example. This is along those lines.

                                            If I observe too much, I tend to get super caught up in tiny details and end up losing the painting. Every such hyperfocused patch ends up being out of harmony with the rest of the artwork. I need this stuff to actually help me loosen up.

                                            #862993
                                            WFMartin
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                                                Bill Martin and David Briggs posts are absolutely correct. Our eyes (and, therefore, brain) perceive the complement of the incident light surrounding the shadow. Call it an optical illusion or neurological phenomenon, it’s how we see. As Bill points out, this was well recognized by the Impressionists.

                                                [B]Using an optical checker is not how we usually see a scene. It eliminates the effect of the light surrounding the shadow has in stimulating our visual perception.[/B]

                                                AMEN ! :thumbsup:

                                                wfmartin. My Blog "Creative Realism"...
                                                https://williamfmartin.blogspot.com

                                                #863011
                                                bongo
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                                                    I remember Don Jusko writing that for outdoor scenes you can get by with just adding some purple to the shadows. I guess the thinking is – outdoors, the sun is the main source of light and it leans toward yellow, so the shadows should lean toward purple.

                                                    http://s3.amazonaws.com/wetcanvas-hdc/Community/images/18-Sep-2019/1999899-sigsmall.jpg
                                                    STUDIOBONGO

                                                    #862994
                                                    WFMartin
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                                                        I remember Don Jusko writing that for outdoor scenes you can get by with just adding some purple to the shadows. I guess the thinking is – outdoors, the sun is the main source of light and it leans toward yellow, so the shadows should lean toward purple.

                                                        That is very true, but the overall concept indicates (by example) that ANY color light source can cause the effect of complementary shadow color, especially in a controlled situation.:)

                                                        wfmartin. My Blog "Creative Realism"...
                                                        https://williamfmartin.blogspot.com

                                                        #863022
                                                        SquishyFishy
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                                                            I noticed that artistic photography of indoor candle/firelight settings does not edit the shadows to match the optical illusion. I did some color picker samples. No complimentary in the shadows. I guess people agree it looks fine without?

                                                            So what would be the diagram for simply using ambient light vs surface color?

                                                            #862999
                                                            oddman99
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                                                                SquishyFishy, if you want to paint like Jack Faragasso, you will have to accept putting complementaries in the shadows. Examine his paintings on the Internet, if you will, and you will see his use of this optical illusion.

                                                                The optical illusion is how we normally see. Portraying it gives life to your images. Restricting your painting to the local colour of the shadowed surface will result in a lifeless image. This was one of the great painting lessons taught us by the Impressionists.

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