01 · COLOR
Different colours do not transmit the spectrum in the same way
Grey and brown lenses with the same 75% tint label may transmit different parts of visible light in different proportions.
The overall view can therefore feel different in colour temperature, contrast and colour emphasis even when both appear similarly dark.
A grey and a brown lens carrying the same 75% label can look different because tint colour changes wavelength-by-wavelength transmission. Grey is often designed toward a relatively neutral spectral balance, while brown or amber designs may reduce some shorter wavelengths more strongly. Average darkness can therefore be similar while colour temperature and perceived contrast differ.
02 · SPECTRUM
One tint number does not mean every wavelength is reduced equally
Tinted lenses have colour-dependent spectral transmission. A single tint percentage cannot describe that entire distribution.
When a precise comparison is needed, measured VLT and spectral transmission provide more information than the tint label alone.
A single darkness number does not reveal the detailed transmission spectrum. Two lenses can have similar average visible transmission while one attenuates the spectrum fairly evenly and the other suppresses selected bands more strongly. Perceived brightness reflects both that spectral distribution and the wavelength sensitivity of human vision.
03 · MIRROR
Surface treatments can change the finished brightness
Mirror coatings can be added on top of a base tint. Different mirror types and strengths can change the final amount of visible light reaching the eye.
A base tint value by itself may therefore not predict the finished lens.
Mirror and anti-reflective treatments add further layers. A stronger front mirror can reflect additional visible light and reduce final transmission, while a back-surface AR treatment mainly reduces reflections returning toward the eye. Grouping all of these effects under one 75% label hides important differences in the completed lens.
04 · ENVIRONMENT
The same lens feels different in different surroundings
A lens can feel different at a building entrance, in city shade, in open midday sun or over water because the bright areas filling the field of view are different.
Compare sunglasses under lighting that resembles the place where they will actually be used.
Visual adaptation and the surrounding scene also affect how dark a lens feels. The same lens can appear brighter after time in very bright sunlight than immediately after leaving an indoor environment, and the colours of the sky and surroundings change perceived contrast. Different brightness from the same tint label is therefore not necessarily a defect.
05 · PERSON
Personal visual preference remains part of the result
One person may find grey 75% neutral while another prefers brown 75%. Light sensitivity and viewing habits can influence that preference as well.
There is no single colour and tint combination that feels identical to everyone.
The substrate itself can also influence the finished colour. Different materials and refractive indices may require different manufacturing approaches to reach a target tint, and small shifts in the final hue can occur. This is why a tint sample and the finished prescription lens do not always look absolutely identical.
GLANOS LENS CHECK
When comparing the same tint number
Separate grey, brown and other base colours.
Use measured transmission when available.
Check whether a surface treatment is added.
Compare in real outdoor light.
Choose the view that stays comfortable over time.
CAUTION
A single tint number cannot fully predict the view
Colour, coating and product construction can change perceived brightness even when the printed number is the same.
GLANOS EYEWEAR
Eyewear comfort has reasons.
Tint · Colour · VLT · Mirror · Individual preference