Herbarium sheets
A herbarium sheet is a single specimen, pressed and dried, fixed to a stiff card with gummed paper strips, and labelled with the place, the date and the collector. Our sheets come from two cabinets that the society was given in 2012 and 2016, after the owners moved house and had no room for them.
The cabinets held 530 sheets between them. We have photographed all of them. Ferns are in section F, and grasses and sedges are in section G. Each section has its own index, and each sheet has one entry in that index whether or not it has been transcribed.
Sections
| Section | Sheets | Size per sheet |
|---|---|---|
| Ferns (F) | 142 | 1.9 to 3.1 GB |
| Grasses and sedges (G) | 388 | 1.8 to 3.4 GB |
How the sheets are photographed
Each sheet sits on the copy stand under two daylight-balanced lamps set at 45 degrees, so the relief of pressed material shows without glare. A colour target is in every frame. Captures are made in raw, then saved as 16-bit TIFF masters, which is the file we keep and the file described on each entry. A smaller JPEG at 2400 pixels on the long side is made for reading on a screen.
Sheets are never flattened or pressed again. If a frond has come away from the card, we photograph it where it lies and note it in the ledger.
