I am a witness for the prosecution in my former boss’s sex crimes trial. It’s a relatively straightforward role, but I am dreading it. What do I wear to take the stand and testify in open court? — Kate, Los Angeles

We spend a lot of time thinking about and reacting to what the plaintiffs and defendants of trials wear. Just consider the reaction to Amber Heard’s pinstriped suiting and 1930s updos during the Depp-Heard defamation trial, as well as Johnny Depp’s three-piece suits and tightly controlled ponytails. Or the scrutiny given to Elizabeth Holmes when she traded her black tech-wizard turtlenecks for bland blazers and skirts during her fraud trial.

But a lot less attention is paid to what the other players in the drama wear, though obviously it also matters — for reasons both external and internal.

Anyone who takes the stand is likely to influence the opinions of judge, jury and the watching public, whether those people admit it or not. On some subconscious level we are all making judgments about those around us based on silent cues: deciding whether they are reliable, believable, trustworthy, out for self-aggrandizement. When the actual reliability is on the stand, this impulse is only exacerbated.

At the same time, it can be a very scary and intimidating experience to stand in front of a courtroom. Clothes can be a source of strength and security.

Many courts have their own dress codes, though they generally dictate what not to wear. In the Superior Court of California, County of Calaveras, for example, it is specified, “No person shall appear in court barefoot, shirtless, wearing a tank top, shorts, wearing sunglasses, or dress in any manner reflecting poorly upon the dignity of the court and its decorum.”

That still leaves a host of options, of course.

Most lawyers advise being as neutral as possible when it comes to image in a courtroom; you want the focus to be on what you say, not what you are wearing. (Note: This is different from being as conservative as possible.) So no bright colors, loud prints, jangling decorations or clothes that require endless tugging, adjusting or other sort of fiddling. The same approach goes for accessories, especially shoes and jewelry.

As Debra Katz, a civil rights lawyer and founding partner of Katz Banks Kumin, said: “You don’t want a jury to make any assumptions about a witness based on what the witness is wearing or the stereotypes they have. You don’t know what biases exist, so you want to avoid anything that can trigger an emotional response.”

Even the smallest detail can send a signal — an American flag lapel pin, for example, or a religious symbol. That’s not to say that you shouldn’t wear such items but that you should consider how they may shape the perception of who are you and frame testimony about factual events.

A friend who has testified in a similar situation said that she opted for a car coat over a simple sweater and skirt because it made her feel protected. This worked because the coat was a light wool, almost like a duster; wearing a puffer indoors might have looked a bit strange.

Ms. Katz points out that most lawyers have a go-to suit for big court moments; witnesses may have a similar outfit. Indeed, when Kate Moss, someone who knows a thing or two about the power of clothes to send a message, testified over video at the Johnny Depp trial, she did so in a black trouser suit and white polka-dot blouse with little makeup or visible jewelry.

She looked pretty much like a model witness.

Your Style Questions, Answered

Every week on Open Thread, Vanessa will answer a reader’s fashion-related question, which you can send to her anytime via email or Twitter. Questions are edited and condensed.