Mix two colors in LAB color space

I have two colors in LAB color space, for example:

blue: 32.303, 79.197, -107.864 (hex code: #0000ff)
yellow: 97.138, -21.556, 94.482 (hex code: #ffff00)

I want to mix these two colors, and get the result color (hopefully some green in this case). Any ideas how to accomplish this?

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The coloring flag is for graph colourings. The tag descriptions are displayed in the tag selection interface, so you can use them to decide which tags are appropriate. –  joriki Feb 12 '13 at 9:09
Ok, thank you for pointing this out. –  Tamás Pap Feb 12 '13 at 9:12

I assume you are writing a computer implementation.

LAB is device independent. Your color codes are not, as they will be processed both by software and hardware before you see the colors. As a first approximation, convert your RGB to sRGB, which in this case will act as a reference device-independent color space.

When the sRGB values are obtained, convert to CIEXYZ and then to LAB, as the Wikipedia article on LAB suggests. Thus, write a function to compute $rgb\rightarrow sRGB \rightarrow XYZ \rightarrow L*a*b*$. Once the latter is obtained, you can interpolate linearly, e.g., take the average values of each value, and then perform the inverse transform to get your new RGB codes.

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Thank you for your answer. This is what I just finished implementing. It works good for mixing red with yellow (resulting in orange), but mixing blue with yellow results in a kind of purple. It should be a kind of green, if I'm correct.. –  Tamás Pap Feb 12 '13 at 9:30