Gelatin Silver Prints. The gelatin silver process is the most commonly used chemical process in black-and-white photography, and is the fundamental chemical process for modern analog color photography. As such, films and printing papers available for analog photography rarely rely on any other chemical process to record an image. Reference: Wikipedia
Below are some examples and price guides of gelatin silver prints including photograph signed Harvey Cushing and a black and white photograph of Winston Churchill.

CUSHING, HARVEY WILLIAMS. 1869-1939.
Photograph Signed (“Harvey Cushing”), gelatin silver print, 145 x 95 mm image area, inscribed to Howard C. Naffziger and dated 1920 below signature in lower margin. Matted and framed.
Sold for US$8,287.50 inc. premium at Bonham’s in 2022

ANSEL ADAMS (1902–1984)
Sand Dunes, Sunrise, Death Valley National Monument, California, c. 1948
gelatin silver print, mounted on board, printed 1973-1977
signed in pencil (mount, recto); titled in ink in photographer’s Carmel credit stamp [BMFA 11] (mount, verso)
image/sheet: 191⁄2 x 151⁄2 in. (49.5 x 39.3 cm.)
mount: 277⁄8 x 217⁄8 in. (70.8 x 55.5 cm.)
Sold for USD 21,420 at Christie’s in 2022

Roy Lichtenstein (1923-1997)
FISH AND SKY (CORLETT 50)
Screenprint and silver gelatin photographic print mounted on three-dimensional lenticular offset lithograph on white composition board, 1967, signed in pencil verso, from Ten from Leo Castelli, published by Tanglewood Press, New York, without the window mount, the full sheet, unframed.
Sheet 11 x 14 inches; 279 x 356 mm.
Sold for $5,355 (includes buyer’s premium) at Doyle in 2022

Herman Leonard (American, 1923-2010) , “Louis Armstrong, Paris, 1960”, silver gelatin print, signed, titled, dated and numbered “38/50” lower margin, 13 in. x 18 1/4 in., framed.
Sold for US$2,400 at Neal Auction Company in 2022