The record behind the sheet in your tube: the file we worked from, what we measured, what we chose and why, what we are allowed to sell, and the framing dimensions for this sheet.
The sheet you have
- Work
- Anna Atkins (1799–1871), Ptilota plumosa, from Photographs of British Algae: Cyanotype Impressions, 1843–1853
- Object
- Cyanotype — a photogram, the seaweed laid on paper coated with iron salts and exposed to sunlight. No camera, no negative, no drawn line. Leaf approximately 27 × 21 cm
- Held by
- The New York Public Library, Spencer Collection — the copy Atkins presented to Sir John Herschel
- Shelf locator
- Spencer Coll. Eng. 1843 93-440
- File
- The library's own IIIF endpoint, 5771 × 7250 px
- Crop
- [139, 120, 5699, 7106] → 5559 × 6986 px, ratio 1.2565, measured by colour threshold
- Printed at
- 30 × 40 cm sheet: leaf 21.49 × 27.00 cm, original size, 1:1 — 657 dpi available
50 × 70 cm sheet: leaf 42.00 × 52.77 cm, 1.95× — 336 dpi available
Which copy, and why this one
Photographs of British Algae is the first book illustrated with photographs, made by one woman over ten years, and only about seventeen copies survive. Ours is the Herschel copy — the one Atkins sent to the man whose process she was using. We printed the Metropolitan Museum's impression of this same plate until 31 August 2026 and replaced it: the New York Public Library's digitisation carries roughly 1.7 times more pixels on each edge, and the Met file fell below 300 dpi at the enlarged size.
What the edges show
This is the most damaged of our five algae sheets and we print it anyway. Measured on the 1:1 print, the corner losses are 2.2 mm at the upper left, 3.8 upper right, 5.4 lower left and 7.1 lower right; at three corners the coating has broken away entirely.
We looked hard at trimming inward and decided against it. A native-resolution scan of all four edges shows that the darker border zones are the sheet's own shadow and its uneven hand coating, not album material — an earlier reading had them wrong. The only foreign matter inside the crop is what shows through the chipped corners, and a rectangular trim cannot remove that without cutting several millimetres off the whole leaf. So nothing is trimmed and nothing is retouched. The whole blue page is the work.
What we are allowed to sell
The work. Made between 1843 and 1853; Atkins died in 1871. Public domain worldwide.
The photograph. The New York Public Library publishes this digitisation as public domain in the United States and asks for credit rather than requiring it — the credit is on the product page.
What we do not claim. A giclée reproduction printed with pigment inks. Not a cyanotype.
Framing this sheet
- 30 × 40 cm sheet
- A 30 × 40 cm frame, no mat. Margins 4.26 cm each side, 6.05 above, 6.95 below.
- 50 × 70 cm sheet
- A 50 × 70 cm frame. Nearest standard 20 × 28 in. Margins 4.00 cm each side, 8.01 above, 9.21 below.
- If you mat it
- A mat will cover the damaged corners. That is a legitimate choice and it is yours — we simply will not make it for you in the file. Cut the window three millimetres inside the printed image. Do not trim the sheet.
Please measure before you buy or cut. These figures describe the file we print from. Sheets are cut by machine to about a millimetre and frames vary between makers. We replace a print that arrives damaged or wrong; we cannot replace a frame or mat that turns out not to fit.
All records: museartis.com/pages/sheet-records · Questions: info@museartis.com