After over thirty-five years as a doctor, I seldom panic. It doesn’t take many patients who are only seconds away from death to teach you the benefits (to both you and the patient) of staying cool and collected, identifying the priorities, and getting on with them without panic. But last week, for the first time in years, I experienced that feeling of welling panic – when I was watching session 210 of Apple’s WWDC. Its title is Introducing Dark Mode.

By the end of that video, I was reeling with its torrent of detail, but one thing I can recall only too clearly: Raymond Sepulveda, from Apple’s Human Interface Design, gave the first and most compelling reason for the introduction of Dark Mode as “dark interfaces are cool.” Expanding on that, he said that dark interfaces are slick, professional, futuristic, and beautiful.

Dark Mode’s starting point is not inverting the display colours, swapping white for black, and so on. If you’ve ever tried that, in the Display section of the Accessibility pane, you’ll know how bizarre that looks. Instead, Dark Mode tries to recreate the dark interfaces we have already experienced in Adobe’s creative apps, other image editors, and Apple’s own Aperture and Final Cut Pro. The first time I can recall seeing this effect was nearly twenty-five years ago in Bryce, a 3D fractal design app with a renegade interface.

When working with images and video, a dark interface is not just cool, but a valuable enhancement. However, the interfaces of current apps which are darkened have been carefully, and individually, designed to make them work and look right, and are by no means uniform or consistent. Most use little true black, instead dealing in shades of grey, and that starts to make things more complex.

In Light Mode, as I’ll refer to the standard macOS human interface, apart from the Desktop and control areas of windows, most of the display is white, with most ‘foreground’ text displayed in black. Colour is introduced sparingly, and most apps simply follow defaults for controls, both for their own simplicity and consistency of the interface.

Dark Mode introduces several complications. One is that the Desktop alters the colour of overlying windows. Apple has come up with an ingenious colour averaging scheme which does this, which is less distracting than simply making windows semi-transparent. This not only changes the tone of windows, but tints them with colour as well.

Only that inconsistency isn’t consistent either: recognising that colour tinting of window content would be a disaster for anyone adjusting the colour of images, or designing a coloured page, that effect can be disabled. As those most likely to benefit from working in Dark Mode are also those most likely want to work with this turned off, I wonder why Apple has even included desktop tinting effects.

Then there are colour accents. Rather than the simple choice between standard Blue Appearance and Graphite, the Mojave user can choose between eight different colours for their controls (in Blue Appearance, those which are shown in blue).

This all came into terrifying context when Raymond Sepulveda showed a slide with a matrix of nine colours. Along the top, Light Mode’s three straight greys for window background, under page background, and content background. Dark Mode doesn’t have three matching colours for those. Instead, it has near-infinite variety, determined by Desktop tinting and the selected accent colour. Although consistent in tone, tinting has dramatic effects.

Then there are what I used to know as icons, now apparently termed glyphs. Those for iCloud, the Trash, a printer, and so on were all designed for display in Light Mode. In Dark Mode, simply inverting their colours isn’t good enough, and does cause some strange effects. So every single glyph used in Light Mode has to be replaced by one designed specifically for Dark Mode.

This may be grand for large software developers, with their dedicated teams of designers tuning their interfaces until they elicit soft sighs of satisfaction. For smaller outfits, and single-handed developers like me (and many of you), this could turn out to be a nightmare. In this introductory session, no one explained how to create simple settings to make a basic app look good in Dark Mode. Does that simple solution even exist?

For the user, the already threatened consistency of Light Mode can only be further fragmented in Dark Mode, as different developers find different design solutions. Dark Mode may be cool, but it also promises to be distressingly inconsistent.

Apple explained that this session would help me “learn the basics of enhancing your app with this new appearance”. Well, if those are the basics, I’m glad I haven’t yet dared watch any sequel. Cool it may be, but isn’t Dark Mode a tad over-designed?

I may just stick to the simpler things in life, like the occasional emergency tracheostomy. At least there are clear and simple instructions for that.