Sheet of "Congo Blue" filter gel (Lee #181, or Rosco #382) costs maybe $8 for 24" sheet Optional: sheet of "Primary Red" filter gel (Lee #106 or Rosco #27)
via amasci.com
For photography tricks, cheap infrared filter.
Sheet of "Congo Blue" filter gel (Lee #181, or Rosco #382) costs maybe $8 for 24" sheet Optional: sheet of "Primary Red" filter gel (Lee #106 or Rosco #27)
For photography tricks, cheap infrared filter.