UCLA flap fold and flip
A trade card from UCLA’s Patent Medicine Trade Cards collection with a single fold-up flap. The lower part of the front sheet hinges upward on one crease and lies face-down over the card, revealing a different portrait printed on its verso. Use the slider to swing the flap, animate it, or flip the card to view the back. The flap is hinged to the sheet rather than printed on one face, so it stays put across a flip: seen from the back it hangs below the card showing its verso upside-down, just as it would on the real object.
Nothing about the fold is stored in a manifest of our own. The page reads UCLA's published IIIF manifest over the network together with one standalone Annotation Page that says which canvas plays which role and where the crease falls, and derives every crop, region and percentage from the two at load time. The diagram at the bottom of the page shows that assembly with the numbers it actually produced.
Assembling fold model…
Fold pattern
The front is one continuous sheet with a single horizontal crease at about 62.75% of its height. Everything below that crease is a flap 37.25% long, hinged on its upper edge. Swinging it upward through 180° carries the free edge to about 25.5% of the sheet and turns the flap's verso to the viewer. There is no accordion: the upper sheet never moves, and the flap is the only hinged part.
The expanded photograph is cropped to the region
15,12,1888,3071 of the source image so that the card fills the same width in both
exposures; without it the two photographs are about 1.4% apart in scale and the flap does not
line up with the sheet.
The verso is invisible in the fully expanded photograph, because in that state it is face-down. It is recovered here as a region of the collapsed photograph, so the flap can show real printed content on both of its sides.
Because the flap is hinged to the sheet rather than printed onto a face, it survives a flip. Turn the card over with the flap open and its verso hangs below the card, upside-down; fold it up first and the flap passes behind the sheet and disappears from view. Only the collapsed back was photographed, so the open back is assembled from that exposure plus the flap's verso.
About this item
Original item: Alphonso & Imogene: an idyl of Henry's Carbolic Salve [inscribed] (ark:/21198/zz0002hh5q) , UCLA Digital Library.
The original record lists the item as a trade card published by John F. Henry & Co. of New York between 1870 and 1906, held by the Louise M. Darling Biomedical Library, History and Special Collections for the Sciences. The source rights statement is “public domain.”
The UCLA IIIF Manifest supplies three canvases: the front collapsed, the front fully expanded, and the back collapsed. Its labels only number the pages, so they cannot say which canvas is the back of a card or where a crease falls. That is the gap this demo fills: it leaves UCLA's record untouched and fetches it as published, and carries the fold in a separate Annotation Page that targets UCLA's canvas ids directly. No derivative manifest, and no local copies of the images, are involved.
How this page is assembled
No derivative manifest is stored here. The fold is described entirely by one Annotation Page, and the numbers below are computed from it at load time, so this diagram shows what the page actually did rather than an idealised version of it.