The first lab dip differs from the target because the recipe is calculated from an estimate and only measurement corrects it. Fibre, structure (single jersey or rib), finishing and even the elastane share change how light reflects and how the dye fixes. This is why 2 to 3 rounds are normal for difficult shades such as navy, red or dark green.
Another reason is the target itself: old or sun-faded samples are hard to match. Give precise feedback (redder, darker, less yellow) and judge under the same light as the lab, not on a screen or in room light.
lab dipcolour matchingtroubleshooting
