The French version/reprint doesn't have that colouring. The colouring in the Spanish issues disappears quickly. The French version seems to have human lettering.
What a coincidence though as I've been asked if I could do a feature on some non English superheroes incl Atomo Kid, for a future issue of Sequential. This coming issue has my piece on jet pack heroes which includes a short section on Atome Kid. Our editor has taken a fancy to an Atomo Kid cover illo for the following number.
I like Atome/Atomo Kid, probably as I've always been fascinated by jet/rocket pack heroes.
Recently, in City Centre Comics, I was chatting to a comic fan/roadie for Placebo, about King of The Rocket Men, Rocket Ranger, Adam Strange and the rest of this sub-genre. Great stuff.