Hi, firstly thanks for making this great software and making it available to everyone.
I just have some questions about how to process the spectral measurements of the pastel set when transforming them into a compatible .csv file for the toolbox to read..
1. I looked in the Xrite chart file built into the toolbox and saw that there are no negative values. I on the other hand have some negative values in my measurements of the pastels. Is that a problem? Can I just sort those measurements out?
2. For some reason my spectrometer does not make measurements as: 301nm 302nm 303nm… but rather several decimal values like: 300.21nm 300.87nm 301.35nm. Is that normal? Is there a way to perhaps automatically average or interpolate the data in e.g. Excel?
3. What is the specific order in which the colors are read in the toolbox? Does it start in the top left corner and read the first row and then do the second row left to right, like one reads a book or is it different?
4. As I am forced to use artificial light (Exo Terra) is there some conversion I should do to my data before using them to account for the discrepancy between natural and artificial light? Or should I just compare e.g. photographs in natural and artificial?
Hope you have time to answer some of these questions.
Heya,
- There shouldn’t be negative reflectance values when measuring your chart. Having negative values likely indicates that something with your reflectance measurements is off (e.g. faulty dark & light calibration).
- Yes, specs don’t usually record readings in neat 1nm or 5nm bins. This has to be done manually by re-binning (i.e. interpolating across the reading data).
- I think it goes top left to bottom right, not sure though. This might be inferrable from the way the values are listed.
- The toolbox is explicitly capable of transforming cone catch estimates from the illuminant that an image is taken under to another one. However, this option is not available when using chart-based calibration. Ultimately, the need to do so depends on your research question and the discrepancy between cone catch estimates derived under your artificial illuminant and the ecologically relevant one.
Cheers,
Cedric