Color modes and what they cost you
The four colour modes production meets are RGB, CMYK, Pantone and grayscale, and each means something specific.
RGB. Built for screens, used in nearly every digital design tool, and not a print colour space, because the additive red-green-blue primary set produces colours that a CMYK print process physically cannot mix. A logo designed in RGB will visibly shift when converted to CMYK: vivid blues lose chroma, neon greens darken, and the brand green that was a particular hex code reads as a slightly muddier green on cotton. The shift is not a defect; it is the gap between what a screen produces from light and what a printer produces from ink. Send the file in its native mode and let production convert it, unless the design was built in CMYK from the start.
CMYK. Built for process printing. Four process inks layered to reproduce a wide gamut, used in screen printing as a four-colour halftone and in direct-to-garment as the native output. CMYK is a smaller gamut than RGB, so a vivid RGB red maps onto a slightly darker CMYK red, and a photographic image looks almost right but never quite. For brand colours that must match a specific reference, CMYK is rarely the right choice. Process printing is process printing, and the result is an approximation rather than a hit.
Pantone. Built for spot printing. A named, pre-mixed ink applied to a substrate as a single colour layer. A Pantone solid is reproduced cleanly on cotton, on polyester, on packaging and on hard goods, and the same reference matches across substrates when the ink is correctly mixed and cured. Brand identities built on a Pantone palette should be ordered in Pantone references rather than converted to CMYK. The supplier delivers a colour match against the physical Pantone standard, typically within one to two Delta-E.
Grayscale. A single-colour layer drawn in black or spot colour, with no chroma information. Used for one-colour apparel prints, etchings, debossings, deboss-and-print marks and any application where the artwork is a tone rather than a colour. The production team will request grayscale for one-colour designs regardless of how the original was authored; the conversion is trivial and submitting the wrong mode adds days of rework.
The cost of sending the wrong mode is almost always a colour-roundtrip delay. The cost of sending the wrong mode against a brand book is a printed batch in the wrong colour on a substrate that cannot be reprinted cheaply. Send the source file with its declared mode and a Pantone reference where one exists, and let production build the per-method output.