What is tone mapping?

Tone mapping is simply a way of re-mapping (changing) one set of colours/tones in an image to another set. So many times I hear people say that they don’t like tone mapping, but anyone who is using photo-editing tools to change/improve the tonal range of their image is actually tone mapping it, just as when we burn and dodge an image in the darkroom process – that’s tone mapping too. Tone mapping copes with the problem of too much contrast in an image but how much you tone map an image is a matter of personal choice and taste. Go too far and it looks grungy with big halos round edges – tone map moderately and the image is simply improved to your taste. The degree of adjustment is entirely up to you.

Tone mapping, pseudo-HDRi and HDRi

Tone mapping is an essential part of HDR imaging, the second stage after creation of the extended dynamic range image from the blend of three or more different exposures…but we can re-map the tones of a single image too. It’s often called pseudo-HDR but personally I prefer to simply call it what it is – “tone mapping”.

Tone mapping a single image in Lightroom 4

For this post I decided to use the same image of Man O’ War Cove as I did in the previous Blog post so that it would make a good comparison.The evaluative metered shot actually does have all the tones in it, but the image is too contrasty and the sky has lost detail.

Working in the RAW

Taking a single image as a jpeg loses information, often clipping highlights and shadows beyond retrieval. I always work in RAW, which will often retain all the highlight and shadow detail except in the most extreme conditions (where bracketed HDR becomes desirable). I then import the image into Lightroom to process it. You can do the same processing in Adobe Camera Raw, from Photoshop – the controls are essentially the same. The tone mapping controls in Lightroom 4 and PS CS6 with ACR7 are better than in the previous versions. If you have previously processed your image in Lightroom 3, you will need to update the settings to the new process by hitting the exclamation mark just below the image preview.

The tone controls

The new tone controls in “process 2012” are a bit less confusing than the previous ones and are aptly named “exposure, contrast, highlights, shadows, whites and blacks”. They are intended to keep up with developments in CCDs and CMOS sensors and offer more control over the tones in the image than before. The original and processed images are shown below.

Original RAW file

Original File


This is the original RAW file as it was imported into Lightroom.

Tone mapped version

Tone mapped


Tone mapped in Lightroom from a single exposure. The processes used are listed below.

 Processing used

  • Automatic lens corrections
  • Reduce highlights using global highlight slider
  • Adjust black point
  • Brighten shadows with shadows slider
  • Reduce whites
  • Adjust overall exposure (down half a stop)
  • Add graduated filter to sky, reducing exposure there 1/3 stop
  • Add graduated filter to foreground, increasing exposure there by 1 stop
  • Increase clarity (mid-tone contrast)
  • Increase vibrance
  • Adjust colour temperature (make warmer by adding yellow)
  • Use brush control to adjust exposure up or down in various parts of the image (like burning and dodging)
  • Add slight vignette

Eh, voila!

 

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