reverse engineering - How is the warm soft quality of photos like this created without impeding the sharpness?

I see photos of this style all the time and I simply can't work out how they create the warmth and softness without sacrificing the sharpness! Is it a filter in a image app, is it a filter? I just can't fathom it.

I've tried modifying curves in Lightroom and tried some filters, but I cannot do this no matter what I try.

http://500px.com/photo/1307940

Answer

This is a duotone/split-tone image (between pink(ish) and green(ish)) + black.

The contrast is lowered, and colors are replaced from a gradient between pink and green.

You see this as "soft" because of reduced saturation, reduced contrast and reduced color jumps.

You see this as warm because the black point is increased (consequence of the reduced contrast) and also the color temperature is a bit lowered.

Maybe this page can help you with achieving this effect.