Sculpted and textured in ZBrush
Painted the color map in Substance Painter
Rendered in Maya with Arnold

The mid-19th century was the time that photography started to become popular throughout Europe and paintings, life masks, … began to fade. Daguerreotypes were very expensive and only the wealthy could afford but so were the masks and paintings!
Luckily there are many photographs of Brahms on the internet, even from his teenage years! I tried to picture him in his thirties (around 1860).