Among the least-expensive services. Weaknesses: Slowest turnaround time. Worst overall image quality. Cost for three slides, three negatives, and three prints: $25.80. Turnaround time: 20 days.

DETROIT — Lower middle-market private equity firm Huron Capital’s portfolio company Exigent Holdco LLC, a provider of mission-critical HVAC, plumbing, and other mechanical system repair, maintenance, ...