Hi micaToolbox/QCPA folks,

First, thank you for creating such a comprehensive set of tools and guides for this kind of work! It’s amazing to be able to go through all these steps in a few minutes with accessible equipment. Much better than cobbling together inherited Matlab scripts…

I have a question about creating a 300-700nm range cone catch model for our camera (Nikon D7000/Coastal Opt 60 mm 1:4 UV-VIS-IR Apo Macro). We have access to a spectrometer & photos of an X-rite colorchecker, so it seems like we just need to buy a set of pastels. Based on the documentation, it sounds like if we’re using pastels & measuring their reflectance curves, we don’t need the colorchecker. So a couple of questions before we navigate COVID restrictions to try and get all these components together:

  1. Is it correct that if we’re using pastels, they essentially replace the colorchecker for creating a 300-700nm cone catch model for a camera?
  2. Is there any advantage to using both the pastels & the colorchecker (i.e. as extra points in the 400-700nm range), and if so, is that feasible or is it more trouble than it’s worth?
  3. Any particular pastel sets that you recommend? We’re assuming that flat-sided ones with a relatively square aspect ratio are best, but other than that we’ll probably just go with the cheapest one we can find.

Any advice you have is appreciated! Many of these photos were collected over several field seasons (including before micaToolbox was released), so we are trying to retrofit our calibration steps for the QCPA pipeline as well as we feasibly can.

Pastel color chart calibration
jolyon Answered question January 8, 2021