Qing Liu is an Oort Postdoc Fellow at Leiden Observatory. He completed his Ph.D. at the University of Toronto in 2024. He received his B.Sc. from the University of Science and Technology of China in 2018. His research interests focus on development of techniques for low surface brightness imaging and photometry, faint diffuse galaxies, and diffuse sky background. He has extensive experience in imaging datasets from CFHT, Gemini, HST, Euclid, Herschel, WISE, and Dragonfly. Qing is a member of the Local Universe science working group of the Euclid Consortium and is engaged in the data team of the ARRAKIHS mission. He has served as a journal referee for AJ, ApJ, and A&A.The faint, diffuse side of the universe remains largely unexplored, yet it offers novel laboratories to test galaxy formation theories and near-field cosmology. Many interesting low surface brightness (LSB) phenomena await to be mapped and understood, such as faint dwarf galaxies, intracluster light, and stellar streams. In the upcoming era of deep wide-field imaging surveys, we will gain access to a wealth of unprecedented datasets ideally suited for LSB science. The scientific payoff, however, is often limited by various systematics such as stray light, PSF, and over-subtraction of the sky background. In this talk, I will introduce Dragonfly, a mosaic telescope optimized for LSB science and a forerunner in this field. I will summarize progress from Dragonfly and share our lessons in observational strategy and data reduction tailored for LSB science. I will highlight our recent work on diffuse Galactic light combining Dragonfly, CFHT, and Euclid data, and discuss why this could be a crucial limiting factor for detection and unbiased measurements of the abovementioned LSB science. These technical advancements will open new opportunities to explore the faint diffuse universe for state-of-the-art or future ground-based and spaceborne telescopes such as Rubin, Euclid, Roman, ARRAKIHS, and CSST.