Here’s a post processing technique to create a stylised blue cast to your image, along with additional work to create depth and a slight glow to skin highlight (creating a “dreamy” effect on skin tones). Here’s a preview of the type of effect this technique will achieve (original lower left diagonal, post processing upper right):
This is a very useful method to even out skin tones and remove blemishes whilst retaining skin texture as much as possible. I’ve used other techniques in the past (inverse high filter passes, gaussian blur layers and various levels of masking) but this method seems to deliver the best results and minimises the risk of over smoothing the skin.
Here’s a handy tip to check if your exposure metering is correct on your old car boot SLRs (or at least the reported exposure). Known as the “Sunny 16 Rule” for reasons that will become apparent; head outside on a bright summer’s day when the sun is high in the sky. Set your camera’s aperture to be F16, set the ISO (or ASA) setting as low as possible (100 or 125), and set your shutter speed to be 125.