mjhjmtu

I want to plot several functions in one plot and have different shades of the same colour for each of the plots. Doing with different colours is easy

a1 = Plot[x^2, x, 0, 10, PlotRange -> All, 
 PlotStyle -> Thick, Red, 
 BaseStyle -> 18, FontFamily -> "Times New Roman", 
 AxesLabel -> "x", "f(X)"];
a2 = Plot[2 x^2, x, 0, 10, PlotRange -> All, 
 PlotStyle -> Thick, Green, 
 BaseStyle -> 18, FontFamily -> "Times New Roman", 
 AxesLabel -> "x", "f(X)"];
a3 = Plot[3 x^2, x, 0, 10, PlotRange -> All, 
 PlotStyle -> Thick, Blue, 
 BaseStyle -> 18, FontFamily -> "Times New Roman", 
 AxesLabel -> "x", "f(X)"];
a4 = Plot[4 x^2, x, 0, 10, PlotRange -> All, 
 PlotStyle -> Thick, Yellow, 
 BaseStyle -> 18, FontFamily -> "Times New Roman", 
 AxesLabel -> "x", "f(X)"];
a5 = Plot[4 x^2, x, 0, 10, PlotRange -> All, 
 PlotStyle -> Thick, Pink, 
 BaseStyle -> 18, FontFamily -> "Times New Roman", 
 AxesLabel -> "x", "f(X)"];
Show[a1, a2, a3, a4, a5] 

But how can I get 5 different shades of red for example?

I tried to use

r1 = LightRed;
r2 = Red;
r3 = Darker[Red];
a1 = Plot[x^2, x, 0, 10, PlotRange -> All, 
 PlotStyle -> Thick, r1, 
 BaseStyle -> 18, FontFamily -> "Times New Roman", 
 AxesLabel -> "x", "f(X)"];
a2 = Plot[2 x^2, x, 0, 10, PlotRange -> All, 
 PlotStyle -> Thick, r2, 
 BaseStyle -> 18, FontFamily -> "Times New Roman", 
 AxesLabel -> "x", "f(X)"];
a3 = Plot[3 x^2, x, 0, 10, PlotRange -> All, 
 PlotStyle -> Thick, r3, 
 BaseStyle -> 18, FontFamily -> "Times New Roman", 
 AxesLabel -> "x", "f(X)"];
Show[a1, a2, a3]

which I found in an answer here, but this only gives three choices.

You can Blend Red with White and Black:

ClearAll[lightToDark]
lightToDark[n_, c_:Red] := Blend[0, White, n/2, c, n + 3, Black, #] & /@ Range[n]

Graphics[Table[lightToDark[10][[x]], Disk[x, 0], x, Range[10]]]

functions = # x^2 & /@ Range[5];
Plot[functions, x, 0, 10, PlotRange -> All, 
 PlotStyle -> lightToDark[Length@functions], 
 BaseStyle -> 18, Thick, FontFamily -> "Times New Roman", 
 AxesLabel -> "x", "f(X)", PlotLegends -> "Expressions"]

What about

col=Table[RGBColor[i, 0, 0], i, 0.5, 1, .1]
GraphicsRow[Map[Graphics[#, Rectangle] &,col]]

or the lighter version

col = Table[RGBColor[1, i, i], i, 0. , .8, .2]
GraphicsRow[Map[Graphics[#, Rectangle] &, col]]

How about this..

 color = Take[Darker[Red, #] & /@ Subdivide[30], 1, -10, 5];
Plot[Evaluate@Table[n x^2, n, 5], x, 0, 10, 
 PlotLegends -> "Expressions", PlotRange -> All, PlotStyle -> color, 
 BaseStyle -> 18, FontFamily -> "Times New Roman", 
 AxesLabel -> "x", "f(x)"]