How to Photograph the Height Marks So Every Height Stays True

Everyone takes a picture of the growth chart before the move. Almost nobody takes one that could be used to rebuild it. A photo from waist height across the hall gives you a memory; it doesn’t give you the heights. Here’s how to shoot it so it does — with the phone you already have, in about fifteen minutes.

We do this for a living, so the method below is what we ask customers for. It’s also just the right way to photograph anything tall and flat.

Why a photo lies

Two reasons, and both are fixable.

Perspective. The column of marks is five feet tall. The lens is at one point. Marks near the lens are bigger in the picture than marks far from it, so a single photo from waist height makes the top and bottom of the chart shrink, and the spacing between marks stops meaning anything. Shooting each section with the lens at that section’s height fixes it.

Lens distortion. Phone cameras, especially the wide and ultra-wide ones, bend straight lines toward the edges of the frame. A doorframe shot on the 0.5× lens bows. Use the main lens, stand back, and keep the marks near the centre of the picture.

The one-minute version

Four steps: measure two marks (and the trim’s width), stand square to the frame, take three overlapping pictures, then upload and set your heights. The details are below.

What you need

• Your phone, lens wiped clean.
• A tape measure. A 25-foot locking tape is ideal; any tape or yardstick will do.
• Daylight, or a lamp you can move.
• A pencil and something to write on.

Step by step

1. Clear the frame. Move whatever’s leaning against it. Take the coat off the hook, and clear anything blocking the lowest marks.

2. (Optional) Run a tape up beside the marks. If you have one handy, hold it flat against the frame — anywhere convenient, not necessarily on the floor — with a bit of painter’s tape at the top. It’s a handy backup while you shoot, not a requirement: what the app actually needs is the two heights you’ll measure and write down in step 9.

3. Turn off the wide lens. On an iPhone, make sure you’re on 1×, not 0.5×. On Android, use the main camera. Don’t zoom in either; digital zoom throws away detail.

4. Stand back four or five feet. Farther is better than closer. From further away the perspective is gentler and the marks in the middle of the shot are true.

5. Shoot in three sections, phone at the height of each. Crouch for the bottom third with the phone at knee height. Stand for the middle. Reach up or stand on a step for the top, phone at the height of the top marks. Each shot square to the frame — not tilted up or down, not angled. Overlap each shot with the next by about a third so they can be stitched.

If the marks span less than three feet, two shots will do. If they run floor to head height, take four.

6. Light it from the side. Daylight from a window to one side is ideal. No flash — it flattens pencil and throws a hot spot on painted trim. If the hall is dark, bring a lamp and put it to one side of the frame at a low angle.

7. Take one raking-light shot. Move the lamp so it skims across the frame almost parallel to the surface. Faint pencil that disappears in flat light shows up under raking light because the graphite sits proud of the paint. This shot is the one that saves the oldest marks.

8. Take one wide shot of the whole frame and a bit of the room. It’s the context, and it’s the one you’ll actually want to look at.

9. Write down two heights. Pick two marks you can read clearly — the farther apart, the better; a mark near the top and one near the bottom works well. Measure each from the finished floor up to the line, to the sixteenth of an inch, and write it down with the name beside it. These two numbers are what calibrates everything, and the floor itself doesn’t need to be in any of the photos. If you have the patience, write down all of them — that’s the ledger, and it’s the backup for every other method.

10. Check the photos before you move on. Zoom in on each one. Can you read the names? Is the frame straight-ish, not bowed? If not, reshoot now. It’s a lot harder from the new house.

Then back them up

Camera rolls get lost with phones. Send the set to yourself by email, put it in a shared album, save it to a cloud folder. Name the folder something you’ll find: “Hallway growth chart — 12 Maple St”. Put the two heights in the same place.

What this makes possible

With three square, overlapping shots and two measured heights, the chart can be rebuilt accurately by anyone, ever. You can trace it onto paper at true size. You can re-mark it on a new frame. And it’s exactly what our software needs: it straightens the photos, stitches them into one image, uses your two heights to calibrate the whole thing to real scale, and produces a life-size canvas print — the pencil lines and handwriting at the height they were made, on a scroll with wooden hangers that you keep measuring on. That’s Keep the Marks. You upload the section shots — up to three; the wide and raking-light shots are for your own records — drag two lines to the marks you measured, type the two heights, and see the print before you decide anything.

Even if you never print it, you’ve done the thing most families wish they’d done.

Common mistakes

One photo from the hall. The top and bottom marks are squashed and the spacing is meaningless.

Ultra-wide lens. The frame bows. Straight lines aren’t straight.

Flash on painted trim. A white glare in the middle and grey pencil that vanishes.

No numbers. The photo is a picture of some lines. Without two measured heights, nobody — including software — can tell how far apart they really are.

Tilting the phone. Angling up at the top marks from waist height, or angling down to try to fit the floor in the shot — both keystone the image and throw off the marks. Keep the phone level, at the height of what’s in that section of the frame; the floor doesn’t need to be visible at all, that’s what the two measured heights are for.

Shooting after the trim is off. Take the photos, and measure your two heights, while the casing is still on the wall — once it’s off there’s no floor to measure from. A stick of trim on the kitchen table has no floor line.

Related

• Every way to save the height marks on your doorframe when you move
• Painting over the height marks? Do these three things first
• Taking the doorframe with you
• Questions people ask about doorframe height marks