Rich, To start with, look at these articles: https://wp.optics.arizona.edu/optomech/wp-content/uploads/sites/53/2016/10/Black-Coatings-to-Reduce-Stray-Light.pdf https://wp.optics.arizona.edu/optomech/wp-content/uploads/sites/53/2016/10/persky-1999.pdf https://e-reports-ext.llnl.gov/pdf/361993.pdf Here's a provider that specializes in black coatings https://www.acktar.com/ I used 3M ECP-2220 Solar Absorber Coating. I bought a gallon of it in 1988 to use in the design of a spectrofluorometer. The resulting stray light in the monochromator compartment was VERY low and easy to apply. Unfortunately I looked but haven't been able to find it on the web (it was listed on the second reference paper I listed in the Review of Scientific Instruments). Regards, Bob Landman H&L Instruments, LLC -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Richard Kraszewski Sent: Friday, November 30, 2018 2:59 PM To: [log in to unmask] Subject: [TN] Need for an Light -Blocking Coating Can anyone recommend a good light blocking coating? I need to block all light from several sides of a component body. Thanks in advance Rich Kraszewski Senior Staff Process Engineer