The photographs of Nabokov's research materials for Lolita and of the author at work with index cards are by Carl Mydans, taken in September 1958 in Ithaca, New York. I found them in the Life photo archive, here and here.
Index cards were gradually loading a shoe box with their compact weight.
The manuscript, mostly a Fair Copy, from which the present text has been faithfully printed, consists of eighty medium-sized index cards, on each of which Shade reserved the pink upper line for headings (canto number, date) and used the fourteen light-blue lines for writing out with a fine nib in a minute, tidy, remarkably clear hand, the text of this poem, skipping a line to indicate double space, and always using a fresh card to begin a new canto.
Pale Fire (1962) [From Charles Kinbote's foreword to his edition of John Shade's poem.]
After a leisurely lunch, prepared by the German cook who came with the house, I would spend another four-hour span in a lawn chair, among the roses and mockingbirds, using lined index cards and a Blackwing pencil, for copying and recopying, rubbing out and writing anew, the scenes I had imagined in the morning.
Foreword to Lolita: A Screenplay (1973)
Nabokov’s unfinished (Review of The Original of Laura)
Raymond Carver's index cards
Writing and index cards