The colour something looks like under specific, real viewing conditions, as opposed to a fixed, condition-independent value.
Apparent colour depends on the light source, surrounding colours, viewing angle, the observer's own colour constancy, and — for a photo — the camera and display involved. It's a more accurate framing for eye colour than treating any single sample as the definitive value.
Talking about a colour's 'apparent' value is not a way of saying the colour isn't real — it's a more accurate description of how colour perception actually works for any object, not just eyes.
An eye's apparent colour in bright sunlight, indoor lamplight and a phone photo can all differ, without any of them being 'the wrong one'.
The core reframe behind Colourwise's eye-colour content: describing a range and its influences, not asserting one fixed, definitive value.
No instrument reads apparent colour directly. A spectrophotometer measures the surface and a calculation under a stated illuminant gives its colorimetric value, which is the same wherever the sample is taken. Predicting how it will look needs a colour-appearance model such as CIECAM16, which takes the light level, the white being adapted to, the background and the surround as further inputs and returns lightness, chroma and hue as they would be perceived. Each of those inputs is one of the 'viewing conditions' that a careful colour specification states.
A paint is chosen from a 5 cm chip and applied to a 20 square metre wall.
Size, surrounding colours, the light in that room and inter-reflection between the walls all change, and the same paint looks stronger than the chip. A large painted sample, moved around the room, is the only reliable preview.
A nearest-match colour is picked by ΔE alone for a different material.
The two agree numerically and differ in gloss, texture and translucency, so they look unalike in place. Treat the numerical nearest as a shortlist and confirm it physically.