About
Natural history collections need rulers in their archival photos, and people working in the field need scale bars. There are way too many scale bar variations out in the wild, which makes measuring them in photos very challenging. Here we provide three computer-vision-friendly, high-contrast rulers that you should be using in all of your photos. Stop using gift cards, coins, hands, or nothing at all! You need a ruler, and we'll give you more rulers than you know what to do with.
How to get your very own ruler
- How large are your objects? NYBG and JSTOR are meant for standard-sized archival situations. Staggered is meant for field conditions, where the subject might be larger or farther from the camera.
- Use 10 cm unless you really need something bigger or smaller. We provide a 1 cm ruler, but use the 5 cm.
- Have fun customizing! Make your own logo, print a ruler for your expedition, put your name on it.
- Print it out. This is the hardest part. Make sure the sheet prints at 100%. We provide brackets for verification: they should precisely enclose a standard ID card or credit card. You can also use calipers or another ruler to measure the full length of the ruler and make sure it printed correctly.
- Try printing on Avery waterproof shipping labels. They stand up to field work and let you stick the ruler to something rigid. We recommend Avery 94268 in Outdoor Waterproof White Film for Laser or Waterproof White Vinyl Film.
FieldPrism
Photographing specimens in the field? FieldPrism is our companion app. Print a field sheet with corner markers, lay your specimen on it, and the app finds the sheet, squares up the photo and sets the scale for you. No ruler needed: the field sheet takes care of scale.
