Electronic configuration of titanium $(Ti) (Z=22)$ is $[ Ar ]_{18} 3 d^{2} 4 s^{2} .$ In case of $Ti ^{4+}$, the electronic configuration will be $[ Ar ]_{18} 3 d^{0} 4 s^{0}$
Similarly, electronic configuration of copper $(Cu) (Z=29)$ is $[ Ar ]_{18} 3 d^{10} 4 s^{1} $ On loosing one electron it acquires stable electronic configuration, i.e $[ Ar ]_{18} 3 d^{10}$
In both $Ti ^{4+}$ and $Cu ^{+}$ no unpaired electron is present. As a result, no $d-d$ transition occur and therefore these are colourless in nature.