cf1[x_] := Hue[2/3 x]
 cf2[x_] := Hue[2/3 - 2/3 x]
 
 Plot3D[{3.5 Log[1.7*x^3 + 0.8*Sin[y] + 3]}, {x, 1, 100}, {y, 10^-5, 
 1}, ColorFunction -> cf1, PlotLegends -> Automatic]
 
 Plot3D[{3.5 Log[1.7*x^3 + 0.8*Sin[y] + 3]}, {x, 1, 100}, {y, 10^-5, 
 1}, ColorFunction -> cf2, PlotLegends -> Automatic]
 
 
 Plot3D[{3.5 Log[1.7*x^3 + 0.8*Sin[y] + 3]}, {x, 1, 100}, {y, 10^-5, 
 1}, ColorFunction -> "Rainbow", PlotLegends -> Automatic]

---

[![enter image description here][1]][1]

[![enter image description here][2]][2]

[![enter image description here][3]][3]


 [1]: https://i.sstatic.net/65KJtqGB.png
 [2]: https://i.sstatic.net/poY6Qrfg.png
 [3]: https://i.sstatic.net/tQUIHGyf.png