LUTI* – the light converting paper

*Intellectual property, all rights reserved to INOVA, Matjaž Mihelčič s.p. Patent No. P 2023 0 0108
LUTI is a trademark registered at EU level and relates to a paper which normalises the reflection of artificial light, the effect being achieved by means of a dye extracted from the Tagetes erecta plant.

The project LUTI

We have developed the first dedicated eco-friendly paper for artificial light conversion on the market. The dye used is based on the Tagetes erecta plant, which efficiently harmonizes the spectrum of artificial light sources. This innovation will potentially have an impact on well-being and general health, and it is ecological. LUTI paper is suitable for all paper media, including paper notebooks in wide daily use. The first notebooks of the experimental series were produced in summer 2023 and are available from INOVA’s office. The companies involved in the project are listed below.

Description

The spectrum of artificial light sources has a significant impact on the human visual system and human physiology in general. In particular, LED lighting emits disproportionate levels of short-wave (blue) light, with some consequences:

– Disturbing circadian rhythms
– Affects cognitive functions

Many studies have shown that disproportionate amounts of blue light, especially when exposed at inappropriate times, have a significant impact on sleep, performance and mood.

In addition to its presence in computer screens, LED technology has also become the dominant lighting method in homes, offices and schools. Unlike working on a computer, however, we do not usually look directly into these light sources, but they are reflected off surfaces – and a very common example of receiving a lot of reflected light is writing on white paper in schools or offices.

The solution to reflected light from paper

We tested different shades of paper paint to see what would make the most physiological composition of the light that otherwise comes from an LED light source and is reflected from the paper to our eyes. We discovered a yellow-orange colour derived from dried leaves of Tagetes erecta. We coloured the paper with a special preparation of the pigment contained in the plant. Tagetes leaves contain lutein, which plays a remarkable role in human and animal retinas and is known for its blue light absorption properties. In our measurements, this tint has been shown to absorb blue light very well and to have better properties in terms of glare than commercial yellow paper. It was also very well received by the test subjects because of its pleasant soft yellow tint.

White 4 … Standard paper 80 g/m2 YL4A … LUTI paper 80 g / m2

Figure 1. Spectral reflectance of the LUTI paper compared to standard white office paper; light spectrum is normalized

Figure 2. Alteration of the 6000 K LED light spectrum (orange) reflected from LUTI paper (magenta)

The benefits of the LUTI paper:

Workbooks, notebooks, books for schoolchildren – besides the more physiological light spectrum, the yellow background is known to enhance the learning effect
Ecological and healthy product – an unprecedented aspect in paper industry