cross hatched surface.
Real Photo - Actual photo on photographic paper, not a

printed image of a photograph.
View Cards - Cards that feature cities and places within

cities. (like Las Vegas or Reno?)
As for size, 3 1/2 x 5 1/2 was the standard, but larger,
over sized, modern cards are 4 x 6. I've heard these called
Continentals.

Here's something I found in Kovels' Antique guide.

The Amt. of postage can help date the card. 1872 (1 cent),
1917 (2 cents),
1919 (1 cent),
1925 (2 cents),
1928 (1 cent),
1952 (2 cents),
1959 (3 cents),
1963 (4 cents),
1968 (5 cents),
1973 (8 cents),
1975 (7 cents),
1976 (9 cents),
1978 (10 cents),
1981 (12 cents),
1981 (13 cents),
1985 (14 cents),
1988 (15 cents),
1991 (19 cents),
1995 (20 cents).