[Solved] How to set up this minimization problem?

Questions
1

labspace[l_, a_, b_, i_, cs_] :=
Block[{}, (List @@
ColorConvert[ColorConvert[LABColor[{l, a, b}], cs],
“LAB”])[[i]]];

lmindata = 
  NMinimize[{labspace[l, a, b, 1, 
     "HSB"], (-1 <= l <= 2) \[And] (-3 <= a <= 9) \[And] (-6 <= b <= 
       2)}, {l, a, b}, AccuracyGoal -> 3, PrecisionGoal -> 3];
Print[lmindata];

… lots of errors follow

Is NMinimize not the correct choice, or ?

2

Richard, I guess you basically have to define your function labspace in a way to prohibit evaluation of non-numeric arguments. Try:

labspace[l_?NumericQ, a_?NumericQ, b_?NumericQ, i_, cs_] := 
 ColorConvert[ColorConvert[LABColor[l, a, b], cs], "LAB"][[i]]