I am a new user trying to make use of the mini-foldable spectrometer with my phone. The images I get have very bright lines and yet the intensity is labeled as 7% or lower. How do I get the intensity up?
That looks much better and makes a good calibration. But note that since your spectrum is curved, the choice of cross-section will shift your calibration left or right depending on what height it is. You'll need to ensure all your data has the same cross-section if you want to compare it or use this calibration for other readings.