It is now generally accepted that Vermeer employed a simple, box-like device, called the camera obscura, as an aid to his painting, although there is great debate as to exactly what extent he did so. Phillip Steadman, a London architect turned Vermeer notable, produced convincing circumstantial evidence (the camera obscura leaves no physical marks of its use in painting) that Vermeer may have even projected image of the camera obscura directly on his canvas where he then comfortable traced its principal outlines with brush and paint.
The camera obscura greatly restricts the complexities of visual phenomena thereby facilitating the painter's job of translating natural phenomena to a simpler reality of paint. Its imperfect lens also produces the so-called halations, or disks of confusion which can be seen in many Vermeer paintings as globular dots of light-toned paint.
In no other work of Vermeer can the optical distortions of the camera obscura are so evidenced as in the late Lacemaker. The foreground objects of the still life have been painted according to an optical reality similar to that created by the camera obscura rather than the conceptual reality. Some of the objects are no longer, or barely recognizable. The threads that issue from the large blue sewing cushion have been transformed into a delightful red and white foam which unceremoniously spills out on the table. The contrast between the world of the still life suspended in its luminous dissolution and the almost painful clarity of the young woman absorbed in her domestic chore, constitutes on the most visually gratifying passages in Vermeer's art.
Although Vermeer certainly made the camera obscura an essential part of his working method, the miniscule Lacemaker possesses a human significance that a mechanical device can neither suggest nor create.