You will need three things:

1. Camera that is able to take a long exposure photograph; at least 2 seconds.
2. iPhone with the Penki App.
3. A darkened space (not completely dark).

So how does it work?

Penki is an app that allows you to paint with light, using an iPhone to create 3D messages and images.

Penki makes a movie that plays out on the phone's screen - over a long exposure photo, the words and messages are visible when the phone is dragged in front of the camera, like this:

Exposure length

Pass duration should be matched to the exposure length on the camera, and longer words will need a longer pass duration.

ISO

Try to keep your camera's ISO between 80 and 200; this will make for a less-grainy photo.

Aperture

If your camera's aperture can be controlled, start with the largest aperture you can (e.g. f2.0 - the lowest f-stop number available); move to a higher f-stop (smaller aperture) if the photo produced is too bright.

iPhone brightness

The iPhone's screen brightness should be set to about 75% (in your phone's settings to avoid light spillage obscuring what you're trying to paint. If using an iPad in 2x mode, this might need to be lower still.

Pass distance

On the setup page, before you start your light painting, Penki will tell you how much distance you need to cover for your word.

Movement of the phone

Movement of the phone needs to ideally be at right angles to the camera taking the photo, with the screen tilted towards the camera.

Dragging the phone

You may find 'dragging' the phone is easier - hold it at one end and leave the screen clear.

Direction of movement

Choose the direction that you're moving in from the menu; either left to right or right to left relative to the camera taking the photo.

Listen to Penki

There's an audio 'pip' for every second of the 'pass'. They start at the first second, and end with a higher-pitched 'pip' for the last second of the pass. For example, for a 5 second 'pass duration' you'll hear 6 pips.

Keep the camera steady

For better results, camera should be mounted on a steady object such as a tripod or table top.

Photo looking very blue?

Then make sure your phone's screen is tilted more towards the camera, particularly with 3G/3GS models of iPhone.

Light painting looks like a glowing box with little detail in your photos?

Your phone's screen may be too bright. Adjust to a lower brightness in your phone's settings.

Light painting appears stretched?

Check on the summary page for the distance that Penki recommends you cover.

Image too dim or lacking in detail?

Try a longer exposure setting, with an increased pass duration.

Problems with Penki?

Please read through the how to and the FAQ on this website, and make sure to check out the help features in the Penki app.

Join the discussion at the Penki Flickr Group to share insights, tips and tricks.

If these resources haven't sorted out your problem, please send us an email at support@penkiapp.com and we will do our best to help you.

Who built Penki?

Penki is published and conceived by Dentsu London, a creative communications agency that believes in Making Future Magic.

Penki was designed and built by BERG.

Penki makes use of the following libraries:

Objective Flickr by Lukhnos D. Liu.

ASIHTTPRequest by All-Seeing Interactive