Among the foundations of visual design are two essential insights, into understanding human vision, and the experience gained from our long history of visual communication. Common to both is the importance of tone (brightness, lightness, etc.) and its contrasts. Not only do around one in twenty males struggle to distinguish some or most colours, but all of us rely on tone to interpret what we see in the absence of information from colours.
This has been illustrated throughout the history of visual art, where those who have excelled in visual communication have placed particular emphasis on tone. Consider Lucas Cranach the Elder (1472–1553) as an example of proven classical methods.
We know a lot about the tonal modelling that Cranach used in his Martyrdom of Saint Catherine painted in 1504-5, through the infra-red reflectogram below, which effectively looks through the paint layer at the underdrawing beneath.
Cranach’s assistants first laid a thin layer of light reddish imprimatura on the white ground of this panel. Once that had dried thoroughly, Cranach himself would have laid down the underdrawing using a pointed brush with carbon black ink. This extended to the tonal modelling shown clearly in the reflectogram.
Following that came undermodelling using grey tones of carbon black and lead white. Some of the darker garments were preceded by a local underpainting of black, a technique popular at the time for dark red fabrics in particular. Much of this seems to have been completed quickly, probably within a single day.
A common practice among masters discards colour altogether and builds the image using tone alone, known as grisaille.
Three centuries after Cranach, the great French illustrator and painter Gustave Doré (1832–1883) painted a group of three works about the Franco-Prussian War entirely in grisaille. Best known among those is The Enigma (souvenirs de 1870), from 1871.
Even a few minutes exposure to a screenful of macOS Tahoe’s windows demonstrates how its new design goes out of its way to ignore those essential insights, and present us with controls that are either bleached- or blacked-out depending on our choice of appearance mode.
In light mode, with default transparency, tool icons and text are clearly distinguished tonally, as are some controls including buttons and checkboxes. However, text entry fields are indistinguishable from the background, and there’s a general lack of demarcation, particularly between the controls and the list view below.
Oddly, dark mode outlines some controls better than light mode, but text entry fields and the list view below still lack demarcation.
One popular mitigation to this lack of tonal contrast is to resort to an Accessibility control that purports to reduce transparency rather than increasing contrast, although in fact its main advantage in Tahoe is to improve tonal contrast, at least in the toolbar.
This still has no effect on controls below the toolbar, and fails to demarcate text entry fields or the list view below.
The elephant in macOS Tahoe is its ignorance of human vision and our long experience of visual communication. It’s an elephant that comes in two appearance modes, bleached-out white or blacked-out black. It has little if any impact on the interface of Apple’s other OS 26es, but it makes macOS a pain to look at and harder to use. I feel sure that Lucas Cranach the Elder, Gustave Doré and every other self-respecting visual artist would be equally offended.