For each color in array, reference in another method to set corresponding color with 50% alpha

I have a method which sets a range of base colors in an array. I then want to set a range of corresponding colors, with 50% alpha, via another method. I realise I can manually set the alpha against each base color, but because my base color array may grow to numerous colors, I thought it would save hassles in future to get the 50% alpha colors in a method. rather than me typing them all in.

     public Color[] colorBase = new Color[6];
     public Color[] colorWithAlpha = new Color[6];

 void Start() {
     SetBaseColors();
     SetColorsWithAlpha();
 }

 void SetBaseColors() {
     colorBase[0] = Color.cyan;
     colorBase[1] = Color.red;
     colorBase[2] = Color.green;
     colorBase[3] = Color.blue;
     colorBase[4] = Color.yellow;
     colorBase[5] = Color.magenta;
 }

// the below doesn't work:

 void SetColorsWithAlpha() {
     Color theColor;
     for (int i = 0; i < colorBase.Length; i++) {
         theColor = colorBase[i].maxColorComponent;
         colorWithAlpha[i].a = theColor * 0.5f;
 }