These meticulous black and white portraits are called 'plumbagos', meaning black lead, but are drawn in graphite or ink.
As small portraits they competed with miniature painting.
There was already a Muslim tradition of miniature painting under the Turko-Afghan Sultanate of Delhi which the Mughals overthrew, and like the Mughals, and the very earliest of Central Asian invaders into the subcontinent, patronized foreign culture.
Mughal paintings are a particular style of South Asian painting, generally confined to miniatures either as book illustrations or as single works to be kept in albums, which emerged from Persian miniature painting (itself largely of Chinese origin), with Indian Hindu, Jain, and Buddhist influences, and developed largely in the court of the Mughal Empire of the 16th to 18th centuries.
Mughal paintings later spread to other Indian courts, both Muslim and Hindu, and later Sikh.
They combine elegant graphite drawings with watercolour, and are on paper not ivory.
It was easier and so quicker to work on paper, so the portraits could be larger and cheaper than true miniatures.
He sketched the figures freely with pencil and painted the faces with dense touches of watercolour.
Smart offered clients a quicker and so cheaper version of his standard oval miniatures.
No miniatures survive from the reign of the founder of the dynasty, Babur, nor does he mention commissioning any in his diaries, the Baburnama.
Copies of this were illustrated by his descendents, Akbar in particular, with many portraits of the many new animals Babur encountered when he invaded India, which are carefully described.
The success of the portrait miniature demonstrated the commercial possibilities of offering small portable portraits to the public.
This section looks at four other small portrait types which competed successfully with the portrait miniature; so-called 'plumbagos', drawn in graphite or ink on vellum; enamels, painted on gold or copper; silhouettes, or as they were called in Britain 'profiles'; and lastly, portraits in watercolour on paper - a quicker and cheaper method than miniature painting.
The cutting of silhouettes, or 'profiles' as they were called in Britain, was a popular pastime in the 18th century.