The Cokin Filter A028 Warm (81C) is a resin filter that adds a warm color tone to your recordings. Blue shades are becoming more orange. The filter has a strength of 1/4th stop and lowers the color temperature from 3600 to 3200 Kelvin. The filter is suitable for use in the A-series filter holder. This 81C has a slightly stronger effect than the 81B version (A027).