Blue is a cool color moving to warm as you add the purplish tones while yellow is a warm color on the other side of the color wheel. To avoid unpleasant vibrations, avoid using in equal amounts. Enliven your blue with a splash of yellow (or calm your yellow with a dash of blue).
From darkest to lightest, the yellow shown with each blue swatch in the above image are:
- Cadium Yellow Hex #FF9912 | RGB 255,153,18 (a warm, brownish yellow)
- Gold Hex #FFD700 | RGB 255,215,0 (SVG color keyword gold)
- Numbers: Hex #FFFF00 | RGB 255,255,0 (SVG/CSS color keyword yellow)
- Very Dark Blue Hex #000033 | RGB 0,0,51 (a browser safe dark blue)
- Midnight Blue Hex #191970 | RGB 25,25,112 (SVG color keyword midnightblue)
- Dark Slate Blue Hex #483D8B RGB 72,61,139 (SVG color keyword darkslateblue; a grayish-purple blue)
- Indigo Hex #4B0082 | RGB 75,0,130 (SVG color keyword indigo; a purplish blue)
- Blue Violet Hex #8A2BE2 | RGB 138,43,226 (SVG color keyword blueviolet)
- Cobalt Blue Hex #3D59AB | RGB 61,89,171
Dark blues and medium shades of blue symbolize importance, confidence, power, intelligence, stability, unity, and conservatism. Colors that push to the violet-purple side of blue can add a touch of mystery, hints of femininity. It adds warmth to the cool blue.
You don't have to use these exact shades. Go a touch lighter or darker, or step one spot to the left or the right on the color wheel. These color combinations are just to help you find a suitable color palette using blue and orange as the main components.