Interestingly, these seem to show that red "rouge" (?) was applied to both subjects' cheeks in the black & white photo/tintype.
The oldest good link I can find with TinEye is this 2013 Tumbler post:
https://joaoalvimcortes.tumblr.com/post/39779207893/tuesday-johnson-ca-1870s-hand-tinted
tuesday-johnson:
ca. 1870s, [hand-tinted tintype portrait of shy-looking girl sitting on her fathers lap]
via the San Francisco Museum of Modern Art
Posted on January 5, 2013
[...]
The SFMOMA link provided in the Tumbler post is dead, but the Internet Archive captured this in January, 2013:
https://web.archive.org/web/20130109015017/http://www.sfmoma.org/explore/collection/artwork/9364
Unknown
Untitled [African-American man and girl]
1870s
photograph | tintype
Not currently on view in the museum
Untitled [African-American man and girl]
https://web.archive.org/web/20121127064701im_/
3 1/8 in. x 4 1/8 in. (7.94 cm x 10.48 cm)
Acquired 1994
Collection SFMOMA
Foto Forum purchase
94.521
There are several "Foto Forums" listed online, but I haven't looked any further in that direction.