Technical notes (and scale bars) All plates have been scanned in 24-bit colour and are presented here completely unedited, except for the inevitable file compression necessary to present them on the web. Each plate is available at two resolutions (other than as a thumbnail): medium and high. The images on each plate are not necessarily at the same magnification. For the plates (but not the searchable image database), we have produced a scale bar you can call up by clicking on one of the links below: Scale bar for medium-resolution images Scale bar for high-resolution images These scale bars allow you to measure the size of the original image as it was drawn. The scale bars are graduated in millimetres; 1 mm on the scale bar is equivalent to 1 mm in the original plate as published. The scale bar images open in new windows. If you are likely to want to use them, open them first, before you open any of the plate images. Then, when you've opened a plate, you can move the appropriate scale bar window around on top of it. Back to 19th Century Diatomists top page