1/16 CTO

116 ctb 1 4 cto 1 2 cto

Subtle warm-tone filter for minimal Color Correction — slightly reduces blue content without visible color cast. Ideal for natural skin tone adjustment in daylight and mixed lighting situations.

Technical Specifications

Color Temperature Shift:

Shift: approx. 45-50 K towards Tungsten (3200 K)
Mired Value: approx. -16 Mired
Output Temperature (from 5600 K): approx. 5550 K

Optical Properties:

Light Loss: approx. 0.1 to 0.2 f-stops (negligible)
Transmission: approx. 99%
Durability: Long lifespan, minimal yellowing with extended storage

Application

The 1/16 CTO filter is extremely weak and is used for:

Subtle Warming: For daylight shots with a blue sky, when only a hint of warmth is needed
Fine Adjustment: When another filter (e.g., 1/4 CTO) is already too strong
Tungsten Fill: Small tungsten fixtures placed next to large daylight sources to correct tungsten to daylight temperature
Cinematic Grading: Subtle color mood in post-production, combined with physical filters
Interior Shots: Correcting daylight through windows with minimal orange cast

Manufacturers & Products

Lee Filters:

Lee 204 (available as a gel snippet in 1/16 quantity)

Rosco:

Rosco 3203 (available in the corresponding strength)

Tiffen:

1/16 CTO (available as a cut gel)

Practical Tips

When to use 1/16 instead of 1/4? The 1/16 CTO is rarely purchased as a standalone filter, as most productions are standardized either fully on daylight or on tungsten. If you need it, it's for a very specific situation with subtle requirements.
Combination with ND filters: The 1/16 CTO is so thin that it practically produces no ND effect and can therefore be combined with neutral density filters without issue.
Snippets instead of full filters: Due to its minimal effect, the 1/16 CTO is often bought only as small gel snippets and attached directly to light fixtures.
Electronic White Balance: With digital cameras, the 1/16 CTO can practically be replaced by Kelvin adjustments (e.g., +50 K) in the camera settings.
Infrequent Use: Compared to 1/2 CTO or 1/4 CTO, the 1/16 CTO is used significantly less often and is often acquired only for specific grading requirements.

From the crafts

Perspectives

Cinematographer

With a 1/16 CTO, you barely have to make any white balance adjustments because this filter is so weak, it's visually almost imperceptible. It's better suited for cinematic subtlety than for functional color correction. Most modern cameras will auto-white balance with this filter on without you needing to intervene.

Gaffer

The 1/16 CTO filter is rarely used, as the majority of productions either go fully Daylight or Tungsten. However, it comes into play when Daylight fixtures (like HMIs or LEDs at 5600 K) need to be warmed up only marginally to achieve a subtle, cinematic look. Sometimes it's also used on exterior shots to specifically achieve minimal warming under a blue sky (higher color temperature).