# Different shades of the same colour in one plot

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[[x]], Disk[{x, 0}]}, {x, Range}]] functions = # x^2 & /@ Range;
Plot[functions, {x, 0, 10}, PlotRange -> All,
PlotStyle -> lightToDark[Length@functions],
BaseStyle -> {18, Thick, FontFamily -> "Times New Roman"},
AxesLabel -> {"x", "f(X)"}, PlotLegends -> "Expressions"] 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]] color = Take[Darker[Red, #] & /@ Subdivide, {1, -10, 5}]; 