Hi All,

I have taken a bunch of photos using a forensic bite mark scale; perfect size to put in photos with the study organism – fungi fruit bodies. It is a commonly used one that you can buy pretty cheaply (e.g. https://www.lociforensics.nl/products/crime-scene-documentation/rulers-photo-scales/abfo-no-2—bitemark-scale). It states in the info for this tool that the reflectance value is about 18, I would like to know if there is a way to double check this somehow? I will be calibrating these photos to extract CIELAB values. I can take RAW photos with this standard and the X-Rite ColorChecker Passport in the same photo, but I have no idea if it is possible to measure reflectance from this. Or do I need to ask around the departments and see if someone has a spectrometer I can use? If push comes to shove, can I use the value of 18 and then double check the photo output somehow? I am just made a bit unsure by the use of ‘about 18%’ in the product information.

Thanks, Sam

Measuring reflectance value for grey standards
Sam Dawson Answered question July 10, 2019