SINGAPORE - The cast of the movie adaptation of Singapore-born author Kevin Kwan's bestselling novel Crazy Rich Asians, about a rich Singaporean family, has been officially announced.

From it, we can glean a couple of things about how Hollywood sees race in 2017.

The first and most obvious thing is that Hollywood thinks that one drop of Asian blood makes a person "Asian" or at least "Asian enough"; this is why it has cast Eurasians such as Henry Golding (a Singapore-based host and social media influencer) and Sonoya Mizuno (La La Land, 2016) as Nick Young and Araminta Lee, both of whom are ethnic Chinese characters.

The next thing one learns from the casting is that it is all about the bottom line. Nobody makes films to lose money, least of all a major studio like Warner Bros. Using a Eurasian leading man in a romantic comedy solves a lot of cross-border marketing problems - Golding's ethnically ambiguous face on a movie poster simply works, from Bangkok to Beijing, from Taipei to Tokyo, and maybe Toronto.

We could talk about how its casting of Eurasians takes roles away from those of full Chinese, Korean and Japanese descent. Korean-American actress Jamie Chung has already vented on this point in an interview.

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But it is wrong to sort actors into "Asian" and "not Asian enough" piles - it sends a message that Eurasians don't belong in our region, when they absolutely do, and have been part of our racial matrix for centuries.

The question to ask about the casting of Golding and Mizuno is why the studio thinks their faces sell tickets. The answer is obvious - it's in our fashion magazines and on advertising billboards, along Orchard Road, or Shibuya, Wan Chai, Bangkok, Manila, Jakarta, Kuala Lumpur and Seoul.

The troubling fact about body aesthetics in our region is that whiter is right-er (and it is also gendered; notice how the leading women's parts are played by Gemma Chan, Michelle Yeoh and Constance Wu, none of whom are Eurasian, but that is a discussion for another time).

So when our own Asian media is saturated with big-eyed, double-lidded, long-limbed, fair-skinned and tall-nosed figures, all selling an ideal of beauty and social status, what is Hollywood to think?

Asian activists in anti-whitewashing crusades, protesting the casting of whites and Eurasians in films are like those who blame McDonald's for causing obesity, while their own cousins, sisters and brothers are in line for a Big Mac meal.

Asians are not alone in elevating white traits. Some African Americans are aware of its existence in their community as well .

Actress Issa Rae from the HBO comedy series Insecure spoke out about how lighter-skinned black women are selected for romantic leads and magazine covers over someone like her, a person with darker skin.

The bias has a name: colourism.

Thankfully, the most common form of colourism in Asia is benign - it's still troubling, but it's harmless. It's seen in the romanticisation and exoticisation of whiteness, and expresses itself in works of fiction, such as anime, with its blonde Barbie-doll Japanese schoolgirls, and in Thai comedies, in which every student in a an ordinary public school just happens to be a white-Thai mix, with nobody pointing out how statistically improbable it is.

This is harmless because most of us can separate fantasy from reality (if we could not, we would be in trouble). In real life we see our brown-skinned, black-haired babies as perfectly beautiful, made with the genes from our gorgeous flat-nosed spouses.

In fashion magazines and billboards in the West, they are trying to stop using images that make young women hate their own bodies - people speak up now if a magazine uses a model who is clearly anorexic, and they are starting to use darker-skinned black models on covers.

Would it be too much to ask that, in a Thai romance, both the leading man and woman looked liked 99 per cent of the population?