Each color card has a padlock. Close one and that color becomes the anchor: the harmony buttons build the other two colors around it and leave it where it is. With all three open, which is how the app starts, a harmony invents a whole palette for you.
What it does
The padlock sits on the top row of each card, after the name and hex code. Open and gray means free; closed and black means locked. Click an open lock to close it; click the closed one to open it again.
- One at a time. Only one color can be locked. Closing another card’s lock opens the first.
- Nothing locked. A harmony button invents a palette: a random starting hue, the harmony’s spacing around the wheel for the three colors, and a saturation and brightness drawn for each. The Ground is kept pale, because the sheet is read against it. A short message says so: “Random harmony — click a lock to build on that color.” To draw another, click the harmony off and on again, or click a different one.
- A color locked. The harmony is built around that color, which does not change. Close a lock while a harmony is switched on and the other two colors are rebuilt around the newly locked one at once.
- A locked black, white or gray has no hue to build from. The locked color still stays exactly as it is, and the harmony draws the other two around a stand-in hue, so locking the black sheet still gives you a palette worth looking at.
- Opening a lock changes nothing on screen. The colors stay; only the next harmony click behaves differently.
A lock guards a color against the harmonies, not against you. You can still edit a locked color with its sliders, its hex code or the wheel. While a harmony is switched on, turn the locked color’s hue and the other two turn with it by the same amount around the painter’s wheel. Turn either of the other two and its partner turns with it, but the locked color stays where it is. The pair then sits off the harmony’s angles from the locked color; click the harmony off and on again to rebuild them around it. Changing a color’s saturation or brightness moves only that color.
Why it works this way
A harmony is a relationship, and a relationship needs a starting point. With nothing locked the app has no way of knowing which color you care about, so it does not guess. Guessing would sometimes throw away a color you were pleased with, with nothing on screen to say why. Instead it treats “nothing locked” as a real choice: surprise me.
That choice also solves a practical problem. A new design starts black on black on white, and a harmony built from black is black. The early versions of the app did exactly that, and the harmony buttons looked broken. Inventing a palette makes them the first thing that works on an empty sheet.
Only one lock can be closed because a harmony grows from one color. With two locked, the harmony would have only one color left to set and could not keep its shape. And the lock is a padlock rather than a set of radio buttons because radio buttons always have one choice made. A lock can be open, and here open means something.
The metaphor
The padlock is one of the most widely understood signs in software: closed means “this will not move”. Design programs use it to lock layers so that a stray click cannot shift them, and a linked chain to lock width to height. Here it says: this color is fixed; build around it.
The metaphor holds for the harmony buttons, which never move a locked color. It is looser than a real padlock in two ways. A real lock stops everyone; this one stops only the harmonies, and you can still change the color yourself. And a locked color is not fixed in appearance. Change the colors around it and it will look different, even though its numbers have not moved. That is not a flaw in the lock but a fact about seeing, and it has a long history.
The single lock also borrows from an older control. Radio buttons are named after the mechanical preset buttons of old car radios, where pushing one in popped the last one out. The locks work the same way, except that you can pop the last one out without pushing another in.
A history
In art
Artists have long built a palette around one fixed color: one a patron insisted on, a fabric, a wall. They have also learned that fixing a color does not fix how it looks. At the Gobelins tapestry works in Paris, where he directed the dyeing, Michel-Eugène Chevreul looked into why some colors in the tapestries seemed to lack strength. He found that the dyes were not at fault: their neighbors were changing them. His book on simultaneous contrast (1839) explained why. Josef Albers turned the discovery into a teaching method. In Interaction of Color (1963) one exercise makes a single color look like two by placing it on two different grounds. A locked color in a notan will do the same as the harmony changes around it. Watch for it.
In printing
Printing has a literal lock. In letterpress the type and spacing for a page, the forme, is set in an iron frame called a chase and locked up with pairs of wedges called quoins, tightened with a key until nothing can move under the pressure of the press. Only then can printing begin. Color work has its own fixed points. A brand color specified by a Pantone number is held constant from job to job, and everything else in a design is chosen to sit with it. On press, the printer measures that ink against its swatch and keeps it there through the run.
In technology
Color tools have long needed a way to mark the color everything is built from. When Adobe launched Kuler in 2006, since renamed Adobe Color, its harmony rules were built around a chosen base color. The padlock itself came into software as an icon for things that cannot be moved or changed: locked layers, locked guides, locked files. Underneath is an idea from mathematics and engineering: to solve for some values, you hold others fixed. A harmony with a locked color is a tiny version of that: one value pinned, two solved.
In professional software
In palette tools the locked color is usually called the base color: the one a harmony is built from. What transfers from Studio Notan is the order of work. Decide first which color is fixed, a brand color or a paper you already own, and let the tool find the others.
- Adobe Color. One of the five colors is the base color, marked by a small white triangle under its swatch, and you can make any of the five the base. Change the base and the others move with it to keep the harmony rule, as the two free colors here turn with a locked one.
- Adobe Illustrator. In the ‘Color Guide’ panel, ‘Set base color to the current color’ makes the selected color the base, and the ‘Harmony Rules’ menu builds a group of colors around it. In ‘Recolor Artwork’, the link icon decides whether the harmony colors move together or one at a time.
- Coolors. This web palette generator puts a padlock on every color. Press the spacebar and each unlocked color is replaced, while the locked ones stay. Unlike this app, it lets you lock several colors at once.
- Adobe Photoshop. The lock buttons at the top of the ‘Layers’ panel can lock a layer’s pixels, its position or everything about it, so a stray stroke or drag cannot change it. That is a stronger lock than this one, which guards a color only against the harmony buttons.
What carries over. Anchor a palette on the color you cannot change, then build around it. Check what a lock guards against in each program: here it stops only the harmonies, in Coolors only the generator, while a layer lock stops editing altogether. And remember what no lock can fix, the look of a color among its neighbors: judge the locked color again every time the others change.
Try this
- With every lock open, click a harmony button. Click it again to switch it off, then once more to switch it on. Each time it comes on you get a new palette with the same relationship.
- Give Front a color you like, lock it and click Comp. Front stays; Back and Ground are built around it. Now drag Back’s marker around the wheel: while the harmony is on, all three turn together, Front included.
- Lock Back, select the Ground, and drag its brightness right up and then right down. Back’s numbers never change, but look at how much it seems to.
Going further
What the harmonies do with a locked color is in Color harmonies. The wheel the shape turns on is in Color wheel, and the three colors themselves in Colors.
Books: Josef Albers, Interaction of Color; Michel-Eugène Chevreul, The Principles of Harmony and Contrast of Colours; Donald Norman, The Design of Everyday Things.