As you can see, there were at least three sources of light (two incandescent floods on stands and the window light, but the one next to the table predominated. The drawing is in water-soluble colored pencil and watercolor about 8 x 6 inches.

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Flickr stream with more photos of my visit to AIB
Art Institute of Boston at Lesley University
International Artist magazine, Issue 90
Photo above by Keith MacLelland
This subject is also covered in my book Color and Light: A Guide for the Realist Painter (Amazon), also available signed from my website store.

On the matte sphere there is no highlight. On the glossy sphere in the middle, the highlight is clearly apparent. The mirror-like sphere on the right also has a highlight, which is really a reflection of the light source. The light source is the sun shining through a window.

The right sphere also reflects the scene around the ball, including the white paper background and the dark room behind the camera. In the right ball, you can even see a reflection of the middle ball, with a highlight in the middle of that reflection.

That same pattern of reflections of the paper, room, and neighboring ball is subtly visible in the middle ball as well.

In the middle ball, there is a second, smaller highlight just to the right of the primary highlight. This secondary highlight is the sunlight is reflected three times. The light bounces off the middle ball, bounces back off the right ball, and bounces again off that little highlight on middle ball back to your eye.

So we've arrived at a definition: A highlight is a specular reflection (Latin "speculum"=mirror) of the light source on a shiny surface. The shinier and smoother the surface, the brighter and clearer the highlight.

These three diagrams show what's happening at the surface level. On the matte surface, light arrives from the top left and hits the rough surface. Some light gets absorbed and the rest scatters away in all directions. This is what happens when light hits a matte surface like a sand dune or a sweater.

The glossy surface of the middle ball bounces a a portion of the light at the same relative angle as the incoming light, but some of the light rays hit uneven spots and bounce in random directions. This is like bouncing a golf ball on a country road. It will probably bounce the way you want it to unless the golf ball hits a crack or a pebble.

The mirror-like surface is so smooth that all the light bounces off the surface predictably at the same relative angle, like bouncing a ball off a basketball court. (Edit: a true mirror-like reflection requires a metallic surface, and cannot be achieved by smoothness alone. Thanks, David!)






The six-page article contains a lot more examples and explanation, and it includes artwork that has never been reproduced in print before. I'll talk more on the blog about highlights in real-world examples tomorrow.
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International Artist magazine, Issue 90
This subject is also covered in my book Color and Light: A Guide for the Realist Painter (Amazon), also available signed from my website store.

Cristian Romero has created a free digital tool for analyzing color schemes. All you have to do is drag a "jpg," "png," or "bmp" into a box, and it will output a gamut map. The gamut map shows which colors are inside the color scheme and which are outside.


Here is a painting by Anders Zorn, showing the narrow range of colors used in the picture. The scheme is centered in yellows and oranges. The "extra-gamut" colors (colors that don't appear in the scheme) are magenta, blue, cyan, and green.


This image has a wider gamut, extending across neutral gray at the center of the circle. It has full intensity yellows and reds as well as some cyan, green, and violet. The gamut doesn't reach all the way to the outer edges of the circle because some hues are only partially saturated.


Here's a fine example of a complementary gamut, a narrow slice of the color wheel from orange to cyan-blue.

The gamut mapping idea is useful both for analyzing color schemes, as we see here, but also for generating the color schemes that you want for your picture.
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Further reading and exploration
Christian Romero's KGamut (samples) and free download (It works in Windows with Linux and WINE and it worked fine - openSUSE 12.2. ;-)
There are other digital tools at Live Painting Lessons
There's more about gamut mapping in my book Available on Amazon and signed from my web store.
Gamut Masking, Part 1
Gamut Masking, Part 2

The Chinese edition is published by the Posts & Telecommunications Press in Beijing, under authority of Andrews McMeel.

The photo appears in the new issue of ImagineFX magazine. Thanks for putting me in such good company!

Spectrum 19: The Best in Contemporary Fantastic Art
John Singer Sargent: The Later Portraits
Cover Run: The DC Comics Art of Adam Hughes (Adam Hughes Cover to Cover)

We experimented with your method of gamut masking and mixing color strings. We used pages 123-131 in Color and Light, and also referenced pages 106-107 and 116-117.
For the exercise I brought in some simple photographs for them to copy, because I wanted to take the drawing element out of it, so they could concentrate on the color scheme. On the morning of class I went to the MICA library to find a color wheel to use. 

 In flipping through all the books about color, I could not find a single good color wheel that went to grey in the center. So we had to use the small color wheel in your book on page 75. We used index cards and tape to make the masks. As you can see, some students' first instinct was to photograph it with their phone and bring it back to their seat.  

 I had each student draw the subject twice. We did one small painting in one color gamut, and then their homework is to do another painting of the same scene in the other gamut. Pretty much exactly what you did in your video with the CircusCircus sign. 

 And now I've been inspired to incorporate these ideas into my own painting as well. I'm working on a New York 1940s maritime scene that would be perfect for a cool gamut.

Thanks for the great ideas! ---Patrick O'Brien, MICA

If other instructors are doing class projects based on ideas in Color and Light, please send me photos and a description, and I’ll try to share them on the blog.

And if you want to use Color and Light as your course guide, please let me know. At our little web store, we can offer you discounts on group orders, and I can sign them for each of your students.
MORE INFO:
Color and Light: A Guide for the Realist Painter signed from my web store
Color and Light: A Guide for the Realist Painter on Amazon
All photos by Patrick O'Brien
Previously on GJ:
My painting demo for Patrick's class at MICA 
Jason Dowd's use of C&L at LCAD