Mirror mode for a beam splitter teleprompter

What mirror mode does

Mirror mode flips the script left to right. The words still scroll upward at the speed you set, and the reading line stays where it was. Only the picture is reversed, so held up to a mirror it reads normally.

That is all it changes. It does not turn the script upside down, it does not reverse the order of your lines, and it does not touch the dock. The buttons stay the right way round, so you can still find play, speed and recue while the script itself is backwards.

Press M to flip it, or use the flip button in the dock. Like the other shortcuts, M goes inert while the caret is in the script box, so typing the word "mirror" into a script does not flip the picture in the middle of a take.

If you always read off a rig, /?mirror=1 opens the prompter with the mirror already on. That is worth a bookmark on whichever machine lives under the glass.

Why a rig needs a reversed picture

A beam splitter teleprompter is a sheet of half-silvered glass held at 45 degrees in front of the lens, usually inside a hood that keeps stray light off it. The glass passes some of the light straight through to the camera and reflects the rest back towards you. Your screen sits out of the camera's view, behind the glass, and what you read is its reflection.

The point of the arrangement is that the reflection appears to be in the same place as the lens. You look at the words, the camera sees you looking at it, and there is no sideways glance to a screen parked next to the camera.

A reflection reverses left and right. Send the glass an ordinary picture and the reflection you read comes back backwards. Send it a reversed one and it arrives the right way round. That is the entire reason this button exists.

None of this reaches the camera, which never sees the screen. It sees you, through the glass. Whatever the script is doing behind that glass is invisible in the recording.

Who needs one

Beam splitters are for people who need the words and the lens in the same direction and cannot get them there any other way: a piece to camera at a distance, an interview where you must hold eye contact for minutes at a time, a studio where the camera is far enough back that a phone beside the lens would be unreadable.

If your device is sitting next to the camera and you are reading the screen directly, you do not need a beam splitter and you do not want mirror mode. It only makes the text unreadable. The same goes for a laptop on a desk, a tablet on a stand beside the lens, and a phone in your hand. Leave the button alone. See iPhone and iPad for those setups.

The glass costs you light, too. Part of the light from the scene goes to your eyes instead of the sensor, so the camera sees a slightly darker scene than it would with nothing in front of it. Plan to open up, add light, or both.

Setting the screen up

The software can only reverse the picture left to right. Getting the words the right way up is a matter of how you physically mount the screen, and the answer depends on which side of the glass your rig puts it.

• Screen below the glass, facing up, which is the common arrangement: the top of the screen points away from the camera, towards you.
• Screen above the glass, facing down: the top of the screen points at the camera.

If the words come out upside down, that is a mounting problem rather than a missing button. Rotate the device, or change its display orientation, and the mirror keeps working the same way round it always did.

Do not calculate this. Set it up, turn mirror mode on, and go and stand where you are actually going to stand. If a line reads normally through the glass from that spot, you are set. If it reads backwards, the mirror is off. If it is upside down, the screen is mounted the other way from the one your rig wants.

Two more things worth doing while you are standing there:

• Set the text size from your reading position, not from the operator's chair. A rig usually puts you further from the words than a desk does, and text that is comfortable at the camera can be guesswork at two metres.
• Use fullscreen. It gets the browser's own chrome out of the reflection, and the dock is still reachable inside it. You come back to the same position and the same settings when you leave.

Recue after each take. It sends the script back to the top, which is what you want after a fluffed line, and it saves you dragging a mirrored script by hand, where every drag goes the direction you did not expect.

When to leave it off

Mirror mode off is the right answer for most people reading from most screens. It is a setting for one specific piece of hardware, not a quality improvement, and switching it on without the glass in front of it just makes your script harder to read.

Your browser remembers the setting along with your speed, text size and colours, so a machine that lives under a rig stays set up as a rig while your laptop stays set up as a laptop.

The beam splitter setup post goes further into mounting and framing. For everything else about the tool, start at the prompter.

Questions

What does mirror mode actually flip? The script, left to right. Not the controls, not the scroll direction, and not the order of the lines.

Do I need it for a phone or tablet propped next to the camera? No. Read the screen directly and leave mirror mode off.

Will my recording come out mirrored? No. Your camera never sees the screen, only the scene through the glass. The flip exists entirely on your side of it.

Can I flip it top to bottom? No. The flip is left to right only, because that is the one a single reflection undoes. Anything upside down is a mounting question.

Does the mirror setting stick? Yes, in the browser on that device, along with your other settings. Clearing your browsing data clears it.

Can I start the prompter with the mirror already on? Yes. Open /?mirror=1 and it opens flipped, ready to read.