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), Dictyota dichotoma, in the young state; and in fruit, 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, who invented the process
- Shelf locator
- Spencer Coll. Eng. 1843 93-440
- File
- The library's own IIIF endpoint, 5549 × 7150 px
- Crop
- [134, 120, 5420, 7007] → 5286 × 6887 px, ratio 1.3029, measured by colour threshold
- Printed at
- 30 × 40 cm sheet: leaf 20.72 × 27.00 cm, original size, 1:1 — 648 dpi available
50 × 70 cm sheet: leaf 42.00 × 54.72 cm, 2.03× — 320 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 copy until 31 August 2026 and replaced it: the New York Public Library's digitisation carries roughly 1.7 times more pixels on each edge, which is the difference between an honest enlargement and a soft one. The Met's sheet is also a different plate of the same species; this one shows the plant both young and in fruit.
What the edges show
This is a leaf from a bound album, printed whole. The corners are chipped where the paper was handled — measured on the 1:1 print: 0.6 mm at the upper left, 2.2 upper right, 2.7 lower left, 1.7 lower right. That is the cleanest of our five algae sheets. Foreign matter at the edges measures below 0.4 mm and is invisible at print size, so nothing is trimmed inward.
None of it is retouched. A photogram has no drawn line to correct back to, and the whole blue page is the work — including where the blue is uneven, because Atkins coated the paper by hand.
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. Taken from the library's own endpoint.
What we do not claim. A giclée reproduction printed with pigment inks. Not a cyanotype: a cyanotype is a contact print made in sunlight, and this is not one.
Framing this sheet
- 30 × 40 cm sheet
- A 30 × 40 cm frame, no mat. Margins 4.64 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, 7.11 above, 8.17 below.
- If you mat it
- Go one frame size up and cut the window three millimetres inside the printed image on every side — or leave the chipped corners showing, which is what we would do. 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