How should this be verified? By comparing against a colour chart (ΔE value) and conducting spot checks on the same batch (to check for colour variation within the batch); the formulation (proportions) of spot colours must be recorded. For small-batch colour verification, produce a proof and approve the colour before proceeding to mass production.
How to select? Use four-colour process for full-colour images and spot colours for brand colours — categorise by colour blocks and illustrations; use spot colours for large areas of solid colour (dark colours, gold/silver) to prevent uneven overprinting.
What are the four colours? Four-colour process (CMYK): the overprinting of cyan, magenta, yellow and black to print full-colour images (photographs, gradients); Four-colour printing is cost-effective but has limited colour gamut (vibrant colours may not be reproduced accurately).
For the same logo, four-colour printing produces a ‘close approximation’, whilst spot colour printing yields an ‘exact match’ — the level of precision required for brand colours determines which method to use. This article clearly explains the distinction between spot colours and four-colour printing.
Spot colours and CMYK represent the difference between ‘close’ and ‘exact’: let CMYK handle the layering of images, and let spot colours safeguard brand colours — only by controlling colour can a brand’s recognisability be firmly established.
How is colour matching controlled? Colour matching standards (colour charts, sample boxes): pre-press verification (digital proofing / press proofing), spot checks during printing (colour difference values); Colour deviations in mass production (within the same batch) are controlled in accordance with these standards.
What are spot colours? Spot colour printing (Pantone spot colours): individually mixed inks (fixed colour values), used to print brand colours (logos, primary colour blocks); spot colours offer high colour accuracy (consistent across batches) but incur slightly higher costs (due to an additional printing pass).
