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What Color Do Red and Blue Make?

Red and blue make purple in paint and magenta in light. See why, what sets the exact shade, and how red and blue combine in vector logo artwork and palettes.

Published

Contents
  1. The short answer by context
  2. Why paint and light give different results
  3. What decides the exact shade of purple
  4. How red and blue combine in vector logo artwork
  5. Building a red, purple and blue logo palette
  6. Limits of this answer

Red and blue make purple. Mixing red and blue paint or ink produces a purple or violet. Combining red and blue light, as a screen does, produces magenta, a brighter pinkish purple. Which result you get depends on whether you are mixing pigment or light. In a vector logo, it also depends on how the two colors are combined in the file.

The short answer by context

Context | What red and blue produce | Reason
Paint and pigment (traditional red-yellow-blue wheel) | Purple or violet | Subtractive mixing: each pigment absorbs part of the light, so the mix reflects less than either color alone
Light and screens (RGB) | Magenta | Additive mixing: full red light plus full blue light, with no green
Even digital average of pure RGB red (#FF0000) and pure blue (#0000FF) | #800080, the color named "purple" in HTML and CSS | Each channel is halved: red and blue at about 50 percent, green at zero
Multiply blend mode of pure red over pure blue | Black | Multiply scales each channel by the other layer's value, and the two colors share no channel
Screen blend mode of pure red over pure blue | Magenta | Screen brightens, so the red and blue channels both stay at full strength
Process printing (CMYK) | Usually a deep, muted purple | The result depends on how each color is built from cyan, magenta, yellow and black

Why paint and light give different results

Pigments work by subtraction. A red pigment absorbs most non-red light and a blue pigment absorbs most non-blue light. When you combine them, more light is absorbed overall, so the mixture is darker than either starting color and lands in the purple range. Screens work by addition. Red and blue light emitted together stimulate the eye's red- and blue-sensitive receptors at once, and the result reads as magenta. Magenta is brighter than either input because light is added rather than removed.

What decides the exact shade of purple

  • Color bias: a red that leans toward orange carries yellow, which dulls a purple mix. A red that leans toward pink and a blue that leans toward violet give a cleaner, more saturated result in paint.
  • Proportion: more red pushes the result toward magenta, plum or burgundy. More blue pushes it toward violet or indigo.
  • Color model: the same pair of named colors behaves differently in RGB, CMYK and paint, so a value chosen on screen will not automatically match a printed or painted version.
  • Lightness: adding white produces lavender or lilac. Adding black or a complementary color produces aubergine or other deep purples.

How red and blue combine in vector logo artwork

In vector artwork, each shape has a fill defined as a numerical color value. Overlapping a red shape and a blue shape does not mix them by default. The shape on top covers the one underneath. A purple area appears only in three cases: the designer assigns a purple fill, the top shape is given reduced opacity, or a blend mode is applied. The values below show how the same pure red and pure blue behave under each approach.

Red fill:              #FF0000   (R 255, G 0, B 0)
Blue fill:             #0000FF   (R 0,   G 0, B 255)

Normal, red at 50%
opacity over blue:     approx. #800080  (purple)
Multiply blend:        #000000          (black)
Screen blend:          #FF00FF          (magenta)

The multiply result often surprises people. Multiply is commonly described as mimicking overlapping inks, yet pure RGB red and pure RGB blue multiply to black because they share no channel. If a logo's overlap turns black or muddy instead of purple, the blend mode is the first setting to check.

It also matters whether the overlap is live vector artwork or an embedded raster image. In live vector shapes, you can select the overlap and read or change its fill, opacity and blend settings. If the logo contains an embedded raster image, or you are looking at a raster preview such as a PNG thumbnail, the purple is baked into the pixels. Changing it then means editing or rebuilding the image. A vector file extension alone does not confirm that the overlap is editable paths, so open the file and inspect the objects.

Building a red, purple and blue logo palette

If purple belongs in the palette, define it as its own solid swatch rather than relying on transparency or blend modes to create it. A solid fill reproduces the same way across formats and applications. Transparency effects can be flattened or rendered differently when artwork is exported, placed in other software or sent to print. A named purple swatch also lets anyone working with the file match the color exactly, without reconstructing the overlap settings.

Gradients from red to blue pass through a purple middle, but the middle's appearance depends on how the software interpolates. Blending directly in standard RGB tends to produce a darker, duller midpoint than many viewers expect. Some tools let you interpolate in a perceptual color space, which can keep the middle brighter. Preview the gradient at the sizes and backgrounds where the logo will appear. Also confirm that a solid-color or single-color version of the logo still works where gradients cannot be reproduced.

For delivery, specify the red, blue and purple separately for each output: hex or RGB values for screens and CMYK builds or spot-color references for print. Screen magenta and vivid RGB purples often fall outside what process inks can reproduce. In CMYK, a red is typically built mainly from magenta and yellow and a blue mainly from cyan and magenta. Combining them keeps magenta high while adding both cyan and yellow, which darkens and dulls the result. A printed purple therefore usually needs its own tested CMYK build or a spot color rather than a value converted automatically from screen.

Limits of this answer

This article covers general color-mixing principles and the standard arithmetic of RGB values and blend modes. It does not assess any specific logo, brand palette, paint line or printer, and it gives no Pantone or other spot-color matches. Before finalizing a printed purple, check it against the swatch library you actually use and against a physical proof from the intended printing process.