Plusgreen is a green correction filter used to move a light’s tint toward green. It is often used when matching a controllable source to existing lighting that has a green cast.
Matching a location
A location may contain practicals that cannot all be replaced or corrected individually. Adding an appropriate plusgreen strength to the production light can bring the sources closer together, allowing a more consistent overall white-balance or grading correction. Measure and test the actual lamps; the same filter is not appropriate for every fluorescent or discharge source.
Practical example
Compare the practical and key separately on a neutral reference. Match CCT as needed, then test a fractional plusgreen on the key. Check skin and important wardrobe colours with both sources operating. Matching a neutral patch does not make their spectra identical.
Strength and transmission
Full, half and quarter describe products within a filter family. They are not f-stop values, and stacking or changing brands needs checking. A physical gel changes light by selective transmission; a fixture’s electronic green/magenta adjustment changes the emitter mix and may not produce the same spectrum.
Equipment examples
The Nanlite Forza 300B II illustrates electronic green/magenta adjustment. Compare this with a physical correction gel on the actual source; they need not create the same spectrum.
Related terms
Minusgreen · Duv · CCT (Correlated Colour Temperature) · Colour Mixing
References
LEE Filters: green and magenta correction filters · IES: Duv