Green’s Dictionary of Slang

1. (US) a derog. term for a black person.

1906		Sun (N.Y.) 9 Sept. 3/2: I picked out a plain looking, quietly dressed smudge.
1983		I.L. Allen Lang. of Ethnic Conflict 47: Color Allusions, Other than ‘Black’ and ‘Negro’: […] smudge.
1995		S. Moore In The Cut 98: I have new words for the dictionary. [...] smudge, black person.

2. (UK tramp) a painting or picture.

1912

Leamington Spa Courier 20 Sept. 7/1: There is ‘Dorset Billy,’ the ‘smudge’ (picture) hawker.

3. a photograph.

1934		P. Allingham Cheapjack 37: I then discovered that a ‘mug-faker’ was the general term for a camera or anyone who works it. It also appeared that ‘smudge’ was another word for photograph.
1979		F. Norman Too Many Crooks Spoil the Caper 165: There was not a flicker of recognition in his eyes. I wondered why since, a few days earlier, he’d identified her from a smudge.
2000		J.J. Connolly Layer Cake 53: The old man’s arranged to have her smudges done by one of the guys who charge a couple or three grand a day.
2011		J.J. Connolly Viva La Madness 144: In the safe they found three passports [...] same smudge but different names.
2020		H. Wickstead Soho Typescripts: 7: Photographs – known as ‘smudges’ - were also sold independently, often in packs of five, at bookshops, or in the Soho streets, by men who attached them to coat linings, opening their jackets to reveal their wares.

4. a (gay) pornographic magazine.

1972

B. Rodgers Queens’ Vernacular.

5. a fingerprint.

1944

J. Archibald ‘Defective Bureau’ in Popular Detective 🌐 The prints taken of the fingers of the bearded stiff coincided with Bertillon smudges of a certain citizen named Nicodemus Rudge.