Lee 725

Overview

Lee 725 is the designation for the color effect filter "Old Steel Blue" from the lighting filter range by LEE Filters. It is a colored lighting gel that is placed in front of a light fixture to color the emitted light. The number 725 is the fixed LEE catalog number for this shade.

The color is a cool, slightly desaturated steel blue. LEE describes the filter as "cool wash, useful for highlights" – meaning a cool, broad light wash that is well-suited for creating cool accents and highlights without appearing as strong as a saturated full blue.

Technical Data

LEE provides the filter values for two standardized light sources – daylight (Source C, approx. 6774 K) and artificial light/tungsten (3200 K). The transmission (light passage) is relatively high for a blue filter because it primarily cools the light rather than blocking it significantly.

Available forms (selection):

• Full Sheet: approx. 1.22 m x 0.53 m (48" x 21")
• Cut Sheet: 21" x 24" (approx. 0.53 m x 0.61 m)
• Roll: 25 ft x 48" (approx. 7.62 m x 1.22 m)

On-Set Use

The gel is typically stretched in front of the light source using gel clips or in a filter frame ("Gel Frame"), or attached to barn doors. Typical applications include a cool, "steely" light character – for example, for night, moonlight, or daylight-through-window looks – as well as cool highlights and background separation. Since the filter cools the light rather than coloring it strongly blue, it can be well combined with warmer key lights.

As with all color gels, Lee 725 degrades over time under strong heat (especially from powerful tungsten fixtures) and can fade or warp; sufficient distance from the lamp or a well-ventilated frame will extend its lifespan. Modern LED and HMI sources have lower thermal stress.