Last time in Superhero Color Theory we explained why our main heroes look the way they do. Now it's time to look at the secondary colors and how they often, but not always, signal the presence of a bad guy. Obviously it makes the most sense visually, that to stand apart from a primary colored (red/blue/yellow) hero, you want a secondary colored (purple/green/orange) one. But what do these colors tell us about what type of character the heroes are encountering?

Green and purple is frequently a sign of scientific hubris growing out of control. Purple symbolizes “creativity,” but in comics it can often be refined to creation of powerful science. Combine that with green's growth, or nature, and you have combination that suggests monstrous scientific geniuses:

Look at the heavy hitters for purple and green: Lex Luthor, Braniac, Kang, Molecule Man, Green Goblin, The Lizard, The Hulk, and the original Mandarin. Even Mysterio is pretty smart to pull off his illusions. The Riddler's mind is less science-oriented, but he's still super smart and full of himself, since purple suggests royalty and elitism. That means purple also suggests all these smarties are hands off, preferring lasers, robot doubles, alien rings, or pumpkin bombs to keep them out of melee.

What about Hulk and Lizard you ask? Don't they smash it up? Yes, but they are the weapon that keeps good guy scientists Bruce Banner's and Curt Connor's hands clean. And why is the Hulk listed with the bad guys? Because, while we root for the green goliath, there's no doubt that his appearance is sending the wrong signal to people. It fits his story. Even the green dragon Fin Fang Foom was given purple pants, as they developed him into a super-wise alien from the same planet where the Mandarin gets his power rings.

When purple is paired with orange it starts to become silly. The hubris of royalty and creativity is mixed with the humorous energy of orange. The Joker, Mr. Mxyzptlk, MODOK, and Batroc the Leaper are all played for laughs as much as they are for danger.

The Joker also has lots of green, as well as purple and orange, which makes him a mixture of all three secondary colors, and perhaps therefore the most powerful, enduring opposite of the typical primary-colored superhero. There is also the Kingpin, who is usually shown in white jacket, but purple pants and orange vest. He's playing with people's lives, and the white reminds us that he's not doing it for laughs. He's cold, unfriendly and looking to eternally reign as the boss of bosses.

On the good side is the weird Metamorpho, whose shapeshifting is also played for laughs, and the alien Starfire whose attempt to understand or reproduce Earth customs is unintentionally funny. Their purple and orange help separate them from other heroes and mark them as outsiders.

Rounding out the parings of secondary colors is green and orange, but there are almost no characters of note with this combination. Strangely, the most famous one is a hero, Aquaman. For him, green reflects his natural connection to aquatic creatures, and the orange shows enthusiasm and energy. Outrageous! During his grim hook-handed period, he lost his orange shirt and that enthusiasm. Green and orange are usually for more goofy characters like Doctor Octopus and Ambush Bug (all three of these guys have an animal element to them). This secondary color pairing is a weak point in our theory that secondary colors are for villains.

There are two famous purple and green Spider-Man villains, Green Goblin and the Lizard, who had newer versions, Hobgoblin and Stegron, respectively. Running out of secondary colors, this forced them to both be mainly orange. This ties into how orange is also the color of energy, and these characters brought new energy to old characters. “New energy” is also how the orange-team New Democrat party in Canada brands itself!

If green and purple was science out of control, what about blue and purple? It's another popular combination for baddies. Notice how it's usually for those who are cold technological terrors, like Galactus, The Sentinels, Archangel, and Marvel's Pluto. The purple signals scientific/mechanical prowess again in the first three, but since advanced science and magic are almost two sides of the same coin, Pluto fits as well.

Purple and blue is when noble wisdom is without compassion or joy, not even taking pleasure in the suffering they cause their foes. To get metaphorical on you, it's the raised dais of regal purple, with the blue of the deep, stable sea, falling downward, unrelenting.

So why is hero Hawkeye blue and purple? His jokey nature and self-made techy arrows should be purple and orange to signify a trickster, right? The answer is in his storyline. His origin is that he stopped a robbery, but the police thought he was a bad guy. Then Black Widow (who was evil at the time) led him astray. Hawkeye fails so bad at being a superhero, he can't even get the costume right. He's sending all the wrong signals to the cops, the bad guys, and the reader. He should've gotten lessons from Luke Cage and Booster Gold.

There are a lot of solid green characters, where it can often mean radicalized nature or growth. For instance, Green Arrow is a double-green character. He has long lost his red gloves. His single color reflects a single-minded purpose. He's a Robin Hood who is trying to make a harmonious world for the downtrodden, like a talking Swamp Thing. Green Arrow is more single-minded and less team-oriented than the most of the JLA.

In fact, many of the sole-green characters with ties to nature are closer to vigilantes, or villains, like Man Thing, Poison Ivy, Vulture, and Scorpion. Amora the Enchantress and former villain Rogue are also double-green, but for them it's not so much about a tie to nature, but that power is natural to them. Rogue added primary yellow when she became a hero, and a brown bolero jacket when she became even more grounded.

Green Lantern, despite his name, has a lot of black in his costume, so that the green energy that can grow into whatever he imagines (from giant hands to cars, to giant hands to forcefields), is bolstered by a black confidence, and tempered just a bit his white gloves. They show he's pure, like cops, or butlers who can prove they have clean hands.

Green is probably the most heroic of the secondary colors. If you buy a board game, there's usually red, blue, yellow and green pieces for the four players to fight over. It's not a primary pigment, but it is a primary color in the light spectrum. Maybe that explains it? Or maybe we all just like being reminded of nature.

Red and green together is a clash of complimentary that's Christmas or traffic lights, so we don't see many character with that combination. There's the original Red Skull costume, which is the green of the military and the red of anger. Then there's Vision, who doesn't have much red, but the red makes a pretty strong statement. It reminds of us the robot's passionate nature (he falls in love with Scarlet Witch after all). Vision is mostly green and yellow, like an inverse Iron Man. Both have a yellow symbol on the chest, but rather than having Tony Stark's fiery nature with red, he is more grounded and neutral with green. He's more natural than most robots, and some superheroes.

Yellow and green often signifies energy from natural or mystical source. Think of Iron Fist's chi punch, Loki's illusory magic, Electro's electricity, and Marvel Girl/Phoenix's psychic powers. Phoenix's different color schemes echo her changes from green character with potential for growth, to red burning energy, to white purity of ascension. Her fiery red hair is the constant throughout, which doubles down the intensity in her dark Phoenix phase, showing some imbalance, but hair color is something we'll get into with our next installment of Superhero Color Theory.

Brian McLachlan is a cartoonist whose works appeared in the New Yorker, Nickelodeon Magazine, Dragon, Owl, and more. Read more of his thoughts on his pop culture essay site Deep Thought Balloon. Aaron Hanson is his Merlin.