Colors That Start With U: RGB Values and Hex Codes

By Prof. Raju Vatsavayi

This page lists the 164 colors whose names start with U, each on a swatch with its RGB value, hex code, shade and maker. The whole list, A to Z, starts on the List of Colors.

How this list works: sources, RGB and hex codes, and shades

What the list covers

The list covers the named colors of the web, the colors every browser knows by name, with the numbered variants of the X11 color list they grew from; brand colors whose owners publish their screen values, such as Android Green; the paint colors of Resene, Sherwin-Williams, Benjamin Moore, Behr, Dunn-Edwards, PPG, Glidden, Farrow & Ball, Little Greene, Dulux Australia, Asian Paints, Nerolac and Jotun, each with the screen value its maker publishes; Pantone’s cotton (TCX) colors for fashion and interiors and a few of its paper (TPG) colors, with the screen values a Pantone dealer publishes; a few Crayola colors; and the color names of the xkcd color survey, a 2010 online survey in which people named colors shown on their screens. Pantone sells its own screen values under license, so its rows give a dealer’s screen approximation; match a physical Pantone guide when an exact color matters. RAL offers its screen values in licensed digital libraries, which this edition does not use, so RAL names are left out rather than shown with values copied from other sites. A few Crayola colors are included where Crayola’s own website shows the value; these are screen previews, not measurements of the crayons. A screen value is a maker’s published digital approximation, so paint on a wall looks different in daylight and lamplight, and on a different finish.

Letters go live one at a time; colors starting with A and B were checked on Oct. 11, 2026.

One name, several colors

The same name often belongs to several makers, each with its own color. Afterglow, for one, is a golden ochre at Resene, a soft apricot at Sherwin-Williams, a pale lemon at Dunn-Edwards and a cream in Pantone’s range. That is normal: every maker names its own colors, and no body controls color names. So each version gets its own plate, and the line under the name says whose color it is.

How color is measured: RGB and hex codes

A screen makes every color from three lights: red, green and blue. In the 8-bit sRGB system used on the web, each is set to a number from 0, off, to 255, full strength, and the three numbers together are the RGB value. 0, 0, 0 is black, 255, 255, 255 is white, and 255, 0, 0 is the most saturated red sRGB can show. That gives 256 × 256 × 256, or 16,777,216, possible codes, which is a count of codes rather than of every color the eye can see; screens also differ in the colors they can show.

Screens mix red, green and blue light. Full red plus full green makes yellow; all three at full strength make white; none at all is black.

A hex code writes the same three numbers in base 16, the counting system with the digits 0 to 9 and A to F, two digits for each light, after a # sign. Alice Blue shows how it works:

Red240= F0Green248= F8Blue255= FFHex#F0F8FFAlice Blue

240 is 15 sixteens and 0 ones, and 15 is written F, so 240 becomes F0. A paint chip is a different thing: it reflects light rather than giving it off, so a paint maker’s RGB value is a published digital approximation of the paint, not the paint itself, and a hex code is not an ink or paint recipe.

Some paint notes give a light reflectance value (LRV): the share of light a painted surface reflects, on a scale of 0 to 100. A color has a note only when there is a fact worth telling, such as where its name comes from or how its maker describes it.

How each color gets its shade

Each color gets exactly one shade, worked out from its RGB value rather than from its name. The value is first read in OKLCH, a perceptual color model that approximates how the eye judges lightness (L), chroma or colorfulness (C) and hue (h); OKLCH gives the coordinates, and the twelve shades are GKBook’s own browsing convention. A color with low chroma is white when very light, black when very dark and gray otherwise, and a very light color with only a faint tint counts as white. Every other color is placed by its hue on the wheel below. Reds, oranges and yellows that are dark or muted count as brown, which is why beige, tan and taupe land there; light reds count as pink; and in the band between purple and red, light colors count as pink and darker ones as purple. Every color in the list is then checked by eye against these definitions, and where the eye and the rule differ, the checked shade is used: a blue gray with a clear blue cast goes to blue, a golden mustard to yellow and an olive to green or brown as it looks. Alice Blue and Azure, two web colors, are such pale tints that they are grouped with white; their blue and cyan casts show on their swatches.

The outer ring shows the hues as OKLCH places them; the inner bands show which shade each hue falls in. Colors with low chroma go to white, gray or black, and dark or muted reds, oranges and yellows go to brown.

Each shade has its own page: Black, Blue, Brown, Gray, Green, Orange, Pink, Purple, Red, Violet, White, Yellow.

How many of the colors in this edition fall in each shade. The paint ranges listed here include many whites, grays and beiges, so the neutral shades lead.