See the Girl with a Pearl Earring painting in 10-gigapixel detail – Engadget

The microscope was programmed to instantly focus on the painting and record the images, then stitch whatever together. Particular areas of the painting were recorded in even greater detail using the 3D abilities of the microscopic lense. For those, each pixel was comparable to 1.1 microns, with multiple pictures of each region recorded to develop a topography map, allowing experts to see the differences in paint height and other details.

” The Hirox software application is instantly moving the lens up and down with extremely high accuracy, catching a series of images at various focus [points] and combining them in one fully-focused image,” stated Leonhardt. “The motorized X/Y phase is then moving to the next position, creating a high-resolution panorama.”
In one location of the left eye, you can zoom in to see the pupil and then zoom in much more to see the light source shown because pupil as a number of blobs of paint. Another section reveals 2 small dots of paint Vermeer included to provide texture to the garment.
By changing to 3D mode, that exact same blob of paint on the student can be seen from edge-on, exposing topographic information in the paint and fractures. This kind of detail is exceptionally important for managers, as they can track wear on the painting and check out past restorations.