If you’ve nev­er tried your hand at film­mak­ing, you might assume that its hard­est visu­al chal­lenges are the cre­ation of effects-laden spec­ta­cles: star­ships duk­ing it out in space, mon­sters stomp­ing through major cities, ani­mals speak­ing and danc­ing like Broad­way stars, that sort of thing. But con­sid­er the chal­lenge posed by sim­ply cap­tur­ing a scene set in a bath­room. Almost all such spaces include a large mir­ror, mean­ing that most angles from which you could shoot will vio­late an impor­tant rule cit­ed by Youtu­ber Paul E.T. in the video above: “Don’t show the cam­era in the shot.”

Yet we’ve all seen major motion pic­tures and tele­vi­sion series with scenes not just in bath­rooms but oth­er mir­ror-equipped spaces, from rooms used for inter­ro­gat­ing sus­pects to rooms used for prepar­ing to come out on stage. What’s more, the cam­era often pass­es blithe­ly before these mir­rors with a vam­pire-like lack of a reflec­tion. The tech­niques used to achieve such shots are now mature enough that we may not even notice that what we’re see­ing does­n’t make visu­al sense. How they work is the sub­ject of Paul E.T.‘s inves­ti­ga­tion, begin­ning with an episode of Crim­i­nal: Unit­ed King­dom in which a cam­era some­how floats around a room with a one-way mir­ror, nev­er appear­ing in that mir­ror.

Anoth­er more famil­iar exam­ple comes from Con­tact, direct­ed by the visu­al-effects maven Robert Zemeck­is. In its ear­ly flash­back sequence, an ado­les­cent ver­sion of its astronomer pro­tag­o­nist runs toward the back­ward-track­ing cam­era and reach­es out to open what turns out to be a bath­room med­i­cine cab­i­net, into whose mir­ror we must have — yet can­not pos­si­bly have — been look­ing into the whole time. What we’re see­ing is actu­al­ly a seam­less fusion of two shots, with the “emp­ty” (that is, blue-screen-filled) frame of the cab­i­net mir­ror super­im­posed on the end of the shot of the young actress run­ning toward it. While not tech­ni­cal­ly easy, it’s at least con­cep­tu­al­ly straight­for­ward.

Paul E.T. finds anoth­er, more com­pli­cat­ed mir­ror shot in no less a mas­ter­work of cin­e­ma than Zack Snider’s Suck­er Punch, which tracks all the way around from one side of a set of dress­ing-room mir­rors to the oth­er. “What you’re actu­al­ly see­ing when the cam­era moves is the tran­si­tion­ing from one side of a dupli­cat­ed set to the oth­er,” he explains, “with an invis­i­ble cut spliced in there” — which involves looka­like actress­es lit­er­al­ly try­ing to mir­ror each oth­er’s move­ments. No such elab­o­rate trick­ery for Ruben Östlund’s Force Majeure, which shoots straight-on into a bath­room mir­ror by build­ing the cam­era into the wall, then dig­i­tal­ly eras­ing it in post-pro­duc­tion.

While we do live in an age of “fix it in post” (an instinct with an arguably regret­table effect on cin­e­ma), mir­ror shots, on the whole, still require some degree of fore­sight and inven­tive­ness. Such was the case with that scene from Crim­i­nal: Unit­ed King­dom, which Paul E.T. sim­ply could­n’t fig­ure out on his own. His search for answers led him to e‑mail the episode’s B‑camera oper­a­tor, who explained that the pro­duc­tion involved nei­ther a blue screen nor dou­bles, but “a com­bi­na­tion of well-chore­o­graphed cam­era work and VFX.” The result: a shot that may look unre­mark­able at first, but on clos­er inspec­tion, attests to the sub­tle pow­er of movie mag­ic — or TV mag­ic, at any rate.

Relat­ed con­tent:

The Art of Cre­at­ing Spe­cial Effects in Silent Movies: Inge­nu­ity Before the Age of CGI

This Is What The Matrix Looks Like With­out CGI: A Spe­cial Effects Break­down

How Film­mak­ers Tell Their Sto­ries: Three Insight­ful Video Essays Demys­ti­fy the Craft of Edit­ing, Com­po­si­tion & Col­or

Based in Seoul, Col­in Marshall writes and broad­casts on cities, lan­guage, and cul­ture. His projects include the Sub­stack newslet­ter Books on Cities and the book The State­less City: a Walk through 21st-Cen­tu­ry Los Ange­les. Fol­low him on Twit­ter at @colinmarshall or on Face­book.