Hi,
My team and I are new to the micaToolbox and calibrated photography in general, and this website and the video guides have been a great help to understand it all better – thank you!
We would like to make a chart-based cone-catch model using the colorChecker passport. But we are unsure under which lighting conditions we should photograph the chart to make the model.
As I understand it, according to the user guide, we should preferably take a photograph under natural daylight/an illuminant corresponding to D65. However, we are using a controlled setup for taking photos of our subjects in the lab, using artificial lighting. The illuminant we have available for use in our setup has a color temperature of 5500 K and so, unfortunately, does not correspond to a D65 illuminant.
Then, should we use a photograph of the chart taken under conditions with natural daylight for our cone-catch model, irrespective of the lighting conditions we used in the lab?
I.e., is it possible to make a meaningful cone-catch model based on a photograph taken under lighting conditions that differ from the conditions which the photographs to be transformed are taken under?
Hope my questions make sense – thank you for your time!
Best wishes,
Majken
Hi Majken,
For your purposes, any light with decent output across the range of 400-700nm (or 300-700nm if that’s what you are after) should do. The toolbox automatically applies the equivalent of a ‘von Kries’ correction (i.e. white balancing), when it standardises your image using the reflectance standard. Thus, for as long as you have sufficient light across the relevant parts of your light spectrum, you should be ok. This becomes problematic, say, when you’re interested of visual signalling in light environments where certain wavelengths are missing from the illuminant spectrum.
I hope this helps.
Cheers,
Cedric