<< Graphics`Legend`

<< Graphics`Colors`

h = 6.6260693×(10^(-34));
c = 299792458. ;
k = 1.3806503×(10^(-23));

Mel0 = ((2*h *
                c^2)/λ)^5 (π/(Exp[((h* c)/(λ *k* T))] - 1));

Tmin = 3500;  Tmax = 5500;  Tdelta = 500;

colors = {{Red, Thickness[0.006]}, {NavyBlue, 
            Thickness[0.006]}, {ForestGreen, Thickness[0.006]}, {Violet, 
            Thickness[0.006]}, {Black, Thickness[0.006]}};

\(\(obrazek = 
        Plot[Evaluate[Table[Mel0, {T, Tmin, Tmax, Tdelta}]], {λ, 0. , 
            2800*10^\(-9\)}, 
PlotRange -> 
            All, 
AxesLabel -> {"λ (m)", \*""Meλ0 (W.(m^(-2)))""}, 
TextStyle -> {FontSize -> 11}, 
PlotStyle -> 
            colors, 
PlotLegend -> 
            Table[StringJoin[ToString[T], " K"], {T, Tmin, Tmax, 
                Tdelta}], 
LegendPosition -> { .31, \(- .26\)}, 
LegendSize -> { .4,  .65}, 
LegendShadow -> None];\)\)

Export["c:/PlanckuvZakon.png",  obrazek,  "PNG", 
      ImageSize -> 450]