Reference chart

Grey Shade Chart: Hex and RGB Values

Seven reference points across the 0-255 scale, the two luminance formulas that convert colour to grey, and where the Pantone Cool Gray series fits.

Fig. 1 — The seven values from Table 1 marked on a continuous 0-255 grey gradient, showing how close charcoal, the 18% card and slate sit relative to the full scale.

Why the Same Photo Gives Two Greys

An 8-bit greyscale image stores one value per pixel from 0 to 255: 0 is black, 255 is white, and 118 is the sRGB value that reads as an 18% neutral grey card. When a colour photo is converted to grey, the result depends on which formula does the converting. BT.601 weights the channels 0.299 red, 0.587 green and 0.114 blue. The HDTV standard weights them 0.2126 red, 0.7152 green and 0.0722 blue. The same jacket photo can land on visibly different greys under the two.

The gap is largest for saturated colours and smallest for colours that are already close to neutral. Light heather (RGB 192, 192, 192) has identical red, green and blue values, so both formulas return exactly 192 — a true grey converts to the same tone no matter which weighting is used. Charcoal and slate, which lean slightly blue, differ by about one point between the two formulas.

Table 1 — Reference greys with BT.601 and HDTV computed values

Hex and RGB values for named apparel greys and scale endpoints, with luminance computed under both formulas.
Name	Hex	RGB	BT.601 grey	HDTV grey
Black (8-bit floor)	#000000	0, 0, 0	0	0
Charcoal	#36454F	54, 69, 79	66	67
18% grey card	#767676	118, 118, 118	118	118
Slate	#708090	112, 128, 144	125	126
8-bit midpoint	#808080	128, 128, 128	128	128
Light heather	#C0C0C0	192, 192, 192	192	192
White (8-bit ceiling)	#FFFFFF	255, 255, 255	255	255

11 separately mixed steps in the Pantone Cool Gray series, from Cool Gray 1 (lightest) to Cool Gray 11 (darkest)

Where Pantone Fits

Hex and RGB codes describe a colour on a screen. The Pantone grey series describes a colour as a physically mixed ink, matched to its own printed swatch — Cool Gray 1 at the lightest end through Cool Gray 11 at the darkest, eleven steps in total. A spec sheet that lists a Pantone code alongside a hex value gives you both a screen check and a physical one; a spec sheet with only a colour name gives you neither.

Use Table 1 as the working reference when a listing gives you a hex or RGB code: place the jacket's code next to the nearest row and read off how it compares to charcoal, slate or light heather before ordering.

Questions About Reading the Chart

Why does the same grey look different on two monitors?

Monitor calibration, brightness and colour temperature all shift how a hex value renders. The hex and RGB numbers in Table 1 stay fixed; only the display's interpretation of them changes. Judge the printed or fabric swatch in daylight rather than trusting the screen alone.

What's the difference between RGB grey and Pantone grey?

RGB grey is a screen value built from light; Pantone grey is a physically mixed ink matched to a printed swatch. A jacket's dye lot is closer in spirit to the Pantone approach, which is why a printed swatch card is more reliable than a product photo.

Which grey is the safest neutral to match against everything?

The 18% grey card value, #767676, is the standard neutral reference point. Shades within a step or two of it, like slate, tend to read as balanced mid-greys rather than leaning distinctly warm or cool.