ARTrace app iconARTrace
The 1807 invention, on your phone.

The camera lucida app
for iPhone, reinvented.

ARTrace projects any photo onto real paper through your phone camera, so you can trace the outline by hand. The same trick David Hockney used with a 200-year-old prism — except free, AI-powered, and pocket-sized.

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iPhone mounted above a sketchbook showing a rose template — the screen image lines up with a half-traced pencil rose below, demonstrating the modern camera lucida effect
A 200-year-old idea

What is a camera lucida?

The camera lucida (Latin for “light chamber”) is an optical drawing aid patented by William Hyde Wollaston in 1807. A small prism on a brass arm, mounted over a sheet of paper, lets the artist look down and see a ghostly image of the scene superimposed on the page. The hand follows the floating outline; a pencil traces it.

It was the iPhone of the Romantic era. Ingres used it for portraits. Naturalists used it for botanical plates. Two centuries later, David Hockney famously argued in Secret Knowledge that half the great Renaissance and Baroque painters used one too.

Hand-drawn illustration of a classic 1807 camera lucida: a brass arm clamped to a wooden desk holds a small prism above a sheet of paper, where a half-traced red rose is being drawn from a real rose sitting beside the page

The original camera lucida (1807) — a small prism redirects light from the scene down to the paper.

From prism to pixel

How a phone replicates the optical trick.

Modern camera lucida apps replace the prism with two layers of pixels:

  1. The live camera feed shows your real paper as you point the phone at the desk.
  2. A semi-transparent reference image — a photo, AI generation, or template — is rendered on top of that feed.
  3. The two layers stay locked together while you draw underneath. Your pencil shows through the overlay, so you always see exactly where your line is going.

The optical effect is identical to Wollaston’s prism. The difference is a phone fits in your pocket, costs nothing extra, and can overlay any image — not just whatever’s in front of you.

Hand-drawn illustration of the modern phone-as-camera-lucida setup: a flexible gooseneck stand holds an iPhone screen-down above an open sketchbook; the phone shows a rose illustration that lines up with a half-traced rose on the page below

ARTrace (2026) — the phone is the prism. Same optical principle, two centuries later.

Why ARTrace

The most useful camera lucida ever made.

The classic Camera Lucida app from 2010 turned the iPhone into a Wollaston prism. ARTrace adds three things Wollaston never imagined: a built-in library, AI generation, and photo-to-sketch conversion. Anything you can describe or photograph, you can trace.

AR overlay on any photo

Open the camera, point it at your paper, drop any photo onto the page. Pinch, rotate, lock — the image stays glued to the paper while you trace.

1,000+ ready templates

A curated library of animals, portraits, flowers, lettering and cartoons — pre-converted to clean traceable outlines so you don't have to fiddle.

AI image generation

Describe what you want — “a fox cub sleeping by a river” — and the app generates a sketch-ready outline in seconds.

Photo-to-sketch conversion

Drop any photo from your camera roll. ARTrace turns the noise into a clean line drawing you can trace, with no Photoshop step.

Free to start

Free download, free for tracing your own photos. A subscription unlocks the full template library and unlimited AI generation.

28 languages

The whole app, the templates, and the help text — available in 28 languages. The original camera lucida only spoke Latin.

Three centuries of tracing

Prism, plastic, or pocket.

The camera lucida has been reinvented twice since 1807. Each version solved the same problem with the tech of its era.

ToolYearPriceImage sourcePortable?
Wollaston camera lucida1807≈ $200 (modern repro)Whatever you can sit next toBrass arm + base
Camera Lucida™ AR Drawing (the original app)2010$9.99Photos from camera rolliPhone
ARTrace2026FreePhotos, 1,000+ templates, AI generation, photo-to-sketchiPhone · iPad · Mac · Vision Pro

The original Camera Lucida™ app from Bigidesign is a great piece of mobile history. ARTrace is what came next.

60 seconds to your first traced page

How to use ARTrace as a camera lucida.

Open the app, pick a template or photo, hold your phone above your paper. Pinch to size, tap to lock, then trace with any pencil. There is no rendering, no export, no “save the file” — you just lift the phone away and the drawing is already on the page.

Download on the App StoreFull step-by-step tracing guide →
Common questions

Camera lucida app FAQ.

What is a camera lucida app?
A camera lucida app is a phone app that recreates the effect of the 1807 camera lucida optical device — it overlays a faint image of a reference picture on top of your real paper through the phone camera, so you can trace the outline by hand. ARTrace is a free camera lucida app for iPhone with AR tracing, AI image generation, and 1000+ built-in templates.
Is the original Camera Lucida app the only option for iPhone?
No. The original Camera Lucida™ AR Drawing app pioneered the category in 2010, but there are now several modern alternatives. ARTrace is a free option that adds AR overlay on top of any photo, photo-to-sketch conversion, AI image generation, and a built-in library of more than 1,000 templates.
Is there a free camera lucida app?
Yes. ARTrace is free to download and trace your own photos. A subscription unlocks the full template library, unlimited AI generation, and photo-to-sketch conversion. The core AR tracing — overlaying an image on paper through your camera — is available in the free tier.
How does the camera lucida effect work on a phone?
The phone camera captures the live view of your paper, the app draws a semi-transparent reference image on top of it, and the composite is shown on the phone screen. When you look at the screen while drawing, you see your real pencil strokes underneath the digital outline — so you can trace the outline directly onto the page beneath the phone.
Is the camera lucida technique cheating?
No. The camera lucida has been a legitimate artist's tool since 1807, used by David Hockney, Ingres, and countless others. Tracing is a well-established way to study proportions, composition, and line. It does not replace freehand drawing — it accelerates the slow part of learning so the artist can spend more time on shading, color, and personal style.
Do I need a special phone stand to use a camera lucida app?
A small gooseneck phone holder or any flexible phone stand makes the experience hands-free, but it's not required. ARTrace works perfectly with the phone held in one hand — you just rest your wrist on the table so the projection stays steady while you trace with the other hand.

Want to go deeper? How to trace a photo onto paper walks through the tracing workflow step by step. Drawings to trace is a starter library of beginner-friendly templates.