articles/Landscape/post-pro-page3

The First Stage of Post-Processing - part 3 of 1 2 3 4 5 6

by Mike McNamee Published 01/04/2015

A Tuscan scene before and after tonal adjustment. The histogram at the top indicates a short toal range from the overcast conditions.

Setting the tonal range and exposure
Now comes the really interesting part. We have to set the tonal range for the image and manage the exposure at the same time. Firstly we set whites and blacks. Select the slide for the blacks and whilst holding down the ALT key, move the slider to the left. Initially the screen will go black, but as you move to the left, specific areas will be highlighted. Bring the slider back to the right until these disappear. Repeat the process for the white slider, but this time you will be moving it to the right. This particular image taken in Tuscany was against a very bright sky. Whilst the exposure is technically correct, by increasing the whites it seems overexposed so I have decided to bring it down by half a stop and move the highlights slider completely to the left to reduce the brightness of the sky and also bring out the cloud detail.

Lastly I have moved the shadow slider to the right to bring out some shadow detail in the rolling hills.

The highlights are shown up by either holding down the Alt key while operating the slider (A) or by turning on the clipping warnings at C. (The shadow warning is blue as indicated at C.)

Correcting Lens Distortion and Chromatic Aberration
Every lens can suffer from distortion, in particular wide-angle lenses. ACR and Lightroom have the capability to dial in the lens you used for the image and make the necessary adjustments. There can be limitations on this. For example, I use the Nikon 24mm tilt and shift lens a lot. This lens does not appear in the list of lenses that ACR recognises. Secondly, it is possible with my Nikon D800E to download to the camera lens profiles and have this action performed in camera. So clearly you wouldn't want to repeat this in ACR or Lightroom. I do find the lens correction to be a bit exaggerated and make any corrections required in Photoshop using the Warp tool.

What is essential is to remove chromatic aberration. Where you have dark areas against light areas, for example trees or mountains against the sky, you will get some level of green or purple fringing. Simply checking the 'Remove Chromatic Aberration' gets rid of it. ACR does a great job at this. If, on the odd occasion, it isn't completely successful then you can manually adjust green and purple defringe sliders. Correcting this at this stage is important, as it will require an enormous amount of work to achieve in Photoshop.

• The First Stage of Post-Processing page 1
  
• The First Stage of Post-Processing page 2
  
• The First Stage of Post-Processing page 3
  
• The First Stage of Post-Processing page 4
  
• The First Stage of Post-Processing page 5
  
• The First Stage of Post-Processing page 6
  

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