CTB-008 Color Temperature Blue (Cooling) Filter

The CTB-008 delivers a gentle, proportional blue shift across the visible spectrum without dramatic spectral manipulation. Transmission peaks at 87.2 % in the critical blue region (435 nm) and maintains an average of 83.4 % across the entire blue band, tapering smoothly to 65 % in red wavelengths. The gentle 1.24 blue-to-green ratio and 1.28 blue-to-red ratio ensure natural color balance while imparting a soft cool tone, making it ideal for applications requiring subtle color correction rather than aggressive temperature swings.

Key Advantages

• Smooth Spectral Rolloff - No sharp transitions across green-yellow-red-delivers gradual, visually imperceptible transitions that feel organic to the eye rather than artificially manipulated.
• Balanced Blue-to-Green Ratio - 1.24 ratio preserves skin tone integrity in portraiture and theatrical lighting-critical for close-ups where color casts become obvious.
• Hard-Oxide Ion-Assisted Coating - Withstands repeated thermal cycling and mechanical stress without delamination or spectral drift-ideal for touring shows and field deployment.
• Versatile 83 % Average Blue Transmission - Minimal loss in brightness for stage and cinema applications-combats tungsten warmth without requiring compensatory power increases.
• Custom Formats and Substrates - Available in round, square, and free-form blanks from 5 mm to 450 mm, thickness 0.21-3.8 mm on Borofloat, soda-lime, Schott D263 T, or Corning Eagle XG.

Typical Applications

• Theatrical Stage Lighting - Compensate for aging tungsten fixtures or intentionally warm practical lamps without overpowering subtle scene-setting.
• Broadcast and Studio Portraiture - Shift ambient incandescent key lights toward daylight balance while maintaining natural skin tones and avoiding visible color casts.
• Film Color Grading in Post - Create gentle cool-tone cosmetic shifts in grade-outs or for scenes lit with older tungsten rigs now being color-corrected digitally.
• Architectural Accent Lighting - Shift warm interior wallwash or uplighting toward cooler tones to harmonize with modern glass and steel interiors.
• Scientific Spectrophotometry - Serve as a reference standard or calibration point for wavelength analysis in research where a mild, predictable blue shift is required.

Prototype in days, scale from individual blanks to full production runs. Specify your exact geometry, substrate, and coating preference-we build to order.