I am trying to identify a short story I read years ago. Probably written in the 1950s, give or take a decade. The opening lines were something like, "there were sounds, there were colors." A scientist suddenly finds himself in a world where there is no color, everything is shades of gray. It turns out that this is our own world, only everything has slowed down, so that days or weeks pass while only a second passes in the everyday world. It is all gray because at this speed you can only see with gravity waves, not light waves. Bad guys have dragged him into this microtime world to force him to do something for them, in line with their nefarious plans. Something like, if they release some radioactive material in the microtime world, its slow release of radioactivity at this time scale would mean massive radiation leaked in mere seconds in the real world, leading to multiple deaths. The scientist has to defeat the bad guys and return to the real world. When he was roped into the microtime world, he was shaking hands with a woman to whom he was just being introduced, so she was dragged into the microtime world with him. Of course they fall in love, and plan to immediately get married once they return to the real world at the end of the story. The memory of this story has haunted me for years -- I hav