diff --git a/modules/gmt/modgmt_func.h b/modules/gmt/modgmt_func.h
index 3aa92ac..f6701ba 100644
--- a/modules/gmt/modgmt_func.h
+++ b/modules/gmt/modgmt_func.h
@@ -173,6 +173,7 @@ using Base2String=Base2Struct<std::string>;
 using Base2Coord =Base2Struct<struct gmt_coord>;
 using Base2Region=Base2Struct<struct gmt_region>;
 using Base2Proj  =Base2Struct<struct gmt_projection>;
+using Base2Color =Base2Struct<struct gmt_color>;
 
 // Simple aliases of convertors with default values
 using Base2StringD=Base2StructD<std::string>;
@@ -210,6 +211,44 @@ class Base2NonNeg: public Base2Double
 };
 using Base2NonNegD=DefaultConverter<Base2NonNeg>;
 
+// Convertors for double values which must be in some interval
+template<int32_t Min, int32_t Max>
+class Base2InRange: public Base2Double
+{
+ public:
+ double Convert(const ObjectBase* ob, bool* res, std::string& err)
+ {
+  double t=Base2Double::Convert(ob,res,err);
+  if(res && (t<Min || t>Max) )
+  {
+   *res=false;
+   err="Value mast be in the interval from "+ToString(Min)+" to "+ToString(Max);
+  }
+  return t;
+ }
+};
+template<int32_t Min, int32_t Max>
+using Base2InRangeD=DefaultConverter<Base2InRange<Min,Max> >;
+
+// Definitions for colors
+constexpr int32_t TransMax = 100;
+constexpr int32_t RGBMax   = 255;
+constexpr int32_t HueMax   = 360;
+constexpr int32_t SVMax    = 1;
+constexpr int32_t CMYKMax  = 100;
+
+using Base2Trans  = Base2InRange <0,TransMax>;
+using Base2RGB    = Base2InRange <0,RGBMax  >;
+using Base2Hue    = Base2InRange <0,HueMax  >;
+using Base2SV     = Base2InRange <0,SVMax   >;
+using Base2CMYK   = Base2InRange <0,CMYKMax >;
+
+using Base2TransD = Base2InRangeD<0,TransMax>;
+using Base2RGBD   = Base2InRangeD<0,RGBMax  >;
+using Base2HueD   = Base2InRangeD<0,HueMax  >;
+using Base2SVD    = Base2InRangeD<0,SVMax   >;
+using Base2CMYKD  = Base2InRangeD<0,CMYKMax >;
+
 // Conversion from List to GMTRegion
 /*
 Input:
@@ -663,19 +702,6 @@ class Convert2Struct<struct gmt_projection, ObjectList>
  }
 };
 
-// Helper types
-typedef SearchParameterWDefO<double,DoubleDefaultVal<>,false,PMin<0>,PMax<255> > Base2RGB;
-typedef SearchParameterWDefO<double,DoubleDefaultVal<>,false,PMin<0>,PMax<360> > Base2Hue;
-typedef SearchParameterWDefO<double,DoubleDefaultVal<>,false,PMin<0>,PMax<1  > > Base2SV;
-typedef SearchParameterWDefO<double,DoubleDefaultVal<>,false,PMin<0>,PMax<100> > Base2CMYK;
-typedef SearchParameterWDefO<double,DoubleDefaultVal<>,false,PMin<0>,PMax<100> > Base2Transp;
-
-typedef SearchParameter<double,false,PMin<0>,PMax<255> > BaseM2RGB;
-typedef SearchParameter<double,false,PMin<0>,PMax<360> > BaseM2Hue;
-typedef SearchParameter<double,false,PMin<0>,PMax<1  > > BaseM2SV;
-typedef SearchParameter<double,false,PMin<0>,PMax<100> > BaseM2CMYK;
-typedef SearchParameter<double,false,PMin<0>,PMax<100> > BaseM2Transp;
-
 // Converting List to GMTColor
 /*
 Input:
@@ -695,144 +721,119 @@ template<>
 class Convert2Struct<struct gmt_color, ObjectList>
 {
  public:
- struct gmt_color operator()(const ObjectList* input, bool* issuc) const
+ struct gmt_color operator()(const ObjectList* input, bool* issuc, std::string& err) const
  {
-  struct gmt_color c;
-  auto size=input->Size();
+  struct gmt_color C;
 
-  if(1==size) // Cases 1, 2 and 4
+  if(1==input->Size()) // Cases 1, 2 and 4
   {
-   Base2Color color(input,0);
+   Base2Color color;
    bool suc=true;
-   c=color(&suc);
+   C=color.Convert(input->At(0),&suc,err);
    if(!suc) goto fail; // Conversion failed
-   return c;
+   return C;
   }
 
   // Case 3
   {
+   ONFPar<Base2Color,ObjectGMTColor> color("color");
+   ONPar<Base2TransD> trans("transparency",0);
+   ONPar<Base2RGB> gray("gr(a|e)y"), r("red"), g("green"), b("blue");
+   ONPar<Base2Hue> h("hue");
+   ONPar<Base2SV> s("saturation"), v("value");
+   ONPar<Base2CMYK> c("cyan"), m("magenta"), y("yellow"), k("[blac]k");
+
+   {ParseNamedParameters params(input,color,trans,gray,r,g,b,h,s,v,c,m,y,k); if(!params) {err=params.Error(); goto fail;} } // Fail to parse by variant 3
+
    bool cmodset=false;
-   bool upd;
-   {
-    BaseMT2Color updarg(input,"color");
-    bool suc=true;
-    c=updarg(&upd,&suc);
-    if(upd && !suc) goto fail; // Conversion failed or too many arguments
-   }
+   bool upd=color.Exist();
+
    if(!upd)
    {
     // default color is black
-    c.transparency=0;
-    c.model=gmt_color::GRAY;
-    c.gray=0.0;
+    C.transparency=trans;
+    C.model=gmt_color::GRAY;
+    C.gray=0.0;
    }
+   else C=color;
 
-   {
-    BaseM2Transp t(input,"t","transp","transparency");
-    if(t.Exist())
-    {
-     bool suc=true;
-     c.transparency=t(&suc);
-     if(!suc) goto fail; // Parsing error
-    }
-   }
+   if(trans.Exist()) C.transparency=trans;
 
    // GRAY
+   if(gray.Exist())
    {
-    BaseM2RGB g(input,"gray","grey");
-    if(g.Exist())
-    {
-     if(cmodset) goto fail; // Model already set
-     bool suc=true;
-     c.model=gmt_color::GRAY;
-     c.gray=g(&suc); // Update mode ignored in this case
-     if(!suc) goto fail; // Parsing error
-     cmodset=true;
-    }
+    if(cmodset) {err="Can't select between different color models"; goto fail;} // Model already set
+    C.model=gmt_color::GRAY;
+    C.gray=gray; // Update mode ignored in this case
+    cmodset=true;
    }
 
    // RGB
+   if(r.Exist() || g.Exist() || b.Exist())
    {
-    BaseM2RGB r(input,"r","red"), g(input,"g","green"), b(input,"b","blue");
-    if(r.Exist() || g.Exist() || b.Exist())
-    {
-     if(cmodset) goto fail; // Model already set
-     bool suc=true;
-     c.ToRGB();
-     if(r.Exist()) c.r=r(&suc);
-     if(g.Exist()) c.g=g(&suc);
-     if(b.Exist()) c.b=b(&suc);
-     if(!suc) goto fail; // Parsing error
-     cmodset=true;
-    }
+    if(cmodset) {err="Can't select between different color models"; goto fail;} // Model already set
+    C.ToRGB();
+    if(r.Exist()) C.r=r;
+    if(g.Exist()) C.g=g;
+    if(b.Exist()) C.b=b;
+    cmodset=true;
    }
 
    // HSV
+   if(h.Exist() || s.Exist() || v.Exist())
    {
-    BaseM2Hue h(input,"h","hue");
-    BaseM2SV s(input,"s","sat","saturation"), v(input,"v","val","value");
-    if(h.Exist() || s.Exist() || v.Exist())
-    {
-     if(cmodset) goto fail; // Model already set
-     bool suc=true;
-     c.ToHSV();
-     if(h.Exist()) c.hue=h(&suc);
-     if(s.Exist()) c.saturation=s(&suc);
-     if(v.Exist()) c.value=v(&suc);
-     if(!suc) goto fail; // Parsing error
-     cmodset=true;
-    }
+    if(cmodset) {err="Can't select between different color models"; goto fail;} // Model already set
+    C.ToHSV();
+    if(h.Exist()) C.hue=h;
+    if(s.Exist()) C.saturation=s;
+    if(v.Exist()) C.value=v;
+    cmodset=true;
    }
 
    // CMYK
+   if(c.Exist() || m.Exist() || y.Exist() || k.Exist())
    {
-    BaseM2CMYK cc(input,"c","cyan"), m(input,"m","magenta"), y(input,"y","yellow"), k(input,"k","black");
-    if(cc.Exist() || m.Exist() || y.Exist() || k.Exist())
-    {
-     if(cmodset) goto fail; // Model already set
-     bool suc=true;
-     c.ToCMYK();
-     if(cc.Exist()) c.cyan=cc(&suc);
-     if(m.Exist()) c.magenta=m(&suc);
-     if(y.Exist()) c.yellow=y(&suc);
-     if(k.Exist()) c.black=k(&suc);
-     if(!suc) goto fail; // Parsing error
-     cmodset=true;
-    }
+    if(cmodset) {err="Can't select between different color models"; goto fail;} // Model already set
+    C.ToCMYK();
+    if(c.Exist()) C.cyan=c;
+    if(m.Exist()) C.magenta=m;
+    if(y.Exist()) C.yellow=y;
+    if(k.Exist()) C.black=k;
+    cmodset=true;
    }
-   if(cmodset || upd) return c; // Color created or updated
+
+   if(cmodset || upd) return C; // Color created or updated
   }
 
   // Case 5
-  if(3==size)
+  if(3==input->Size())
   {
-   Base2RGB r(input,0), g(input,1), b(input,2);
-   c.model=gmt_color::RGB;
-   bool suc=true;
-   c.r=r(&suc);
-   c.g=g(&suc);
-   c.b=b(&suc);
-   if(!suc) goto fail; // Parsing error
-   return c;
+   RPosPar<Base2RGB> r("red"), g("green"), b("blue");
+   ParsePositionalParameters params(input,r,g,b);
+
+   if(!params) {err=params.Error(); goto fail;} // Fail to parse by variant 5
+
+   C.model=gmt_color::RGB;
+   C.r=r; C.g=g; C.b=b;
+   return C;
   }
 
   // Case 6
-  if(4==size)
+  if(4==input->Size())
   {
-   Base2CMYK cc(input,0), m(input,1), y(input,2), k(input,3);
-   c.model=gmt_color::CMYK;
-   bool suc=true;
-   c.cyan=cc(&suc);
-   c.magenta=m(&suc);
-   c.yellow=y(&suc);
-   c.black=k(&suc);
-   if(!suc) goto fail; // Parsing error
-   return c;
+   RPosPar<Base2CMYK> c("cyan"), m("magenta"), y("yellow"), k("black");
+   ParsePositionalParameters params(input,c,m,y,k);
+
+   if(!params) {err=params.Error(); goto fail;} // Fail to parse by variant 6
+   C.model=gmt_color::CMYK;
+   C.cyan=c; C.magenta=m; C.yellow=y; C.black=k;
+   return C;
   }
+  err="Incorrect number of arguments";
 
   fail:
   *issuc=false;
-  return c; // Something go wrong
+  return C; // Something go wrong
  }
 };