By the nineteenth century these optical devices became widely known as “Lorrain mirrors” or “Claude glasses.” Their darkened reflections suggested the work of landscape painter Claude Lorrain (1604?-1682). Lorrain himself, though, probably never used them. The name appeared long after his death, and for a time the devices were associated with the English poet, Thomas Gray (1716-1771).
Antique Lorrain mirrors were usually elliptical and slightly convex to allow the viewer to see the entire scene in miniature.
Here’s a simple homemade Lorrain mirror fashioned out of an ordinary piece of glass painted black on one side. The backside and edges were then protected with tape. In a pinch you could get the same effect by looking at the reflection in a lens of your sunglasses cupped in your hand.
For artists nowadays, the benefit of studying a darkened reflection is that it desaturates the colors, reduces the detail, and organizes the tones. By grouping the darks together into large masses, the vista takes on a romantic or picturesque aura. You can immediately see how to proceed with your tonal design. It’s easier to compare the relative brightness of light values—such as clouds compared to white buildings.
Here’s a photo manipulated with Photoshop to simulate the effect. I occasionally use Lorrain mirrors to help me choose a motif, or study it before commencing to paint. They’re also helpful for a mid-course check during the painting. They guard against the tendency we all have to lighten the values of the shadows, which results from our eyes adjusting to the dark areas and seeing too much detail in them.
If you prefer looking through a transparent viewer rather than seeing a reflection in a mirror, you can improvise your own Lorrain glass using a dark gray filter, a welding goggle, or an unexposed piece of film.
In an era before photography, both artists and tourists enjoyed the novelty of looking at real landscapes through gold- or blue-tinted Lorrain glasses. A heroine from an English play dating from 1798 said, as she peered through her warm-tinted glass: “How gorgeously glowing.” Then switching to a dark glass, she said, “How gloomily glaring.” Finally, looking through a cobalt-tinted glass, she exclaimed, “How frigidly frozen.”
Tintern Abbey Viewing Station with live Lorrain mirror webcam. Link.
Archived webcam shots show changes of light through the day. Link.
Final quote from Spectacles and Other Vision Aids: A History and Guide to Collecting, by J. William Rosenthal. p. 276,
Tomorrow: Color Wheel Masking