Tuesday 19 June 2007

Blencathra part 2: the sky for perspective

The first area I usually tackle in a shot like this is the sky. For me it sets the tone of the whole shot and is the best way to give a great sense of depth to the final print. When looking at similar images from others I often think that the total impact is lost from a wishy-washy (technical term) sky.

I find cloudy skies quite easy to get good results. There are smooth tonal transitions built in which makes noise reduction, spotting etc quite easy. Soft edges abound so sharpening isn't critical. Most of the colour information is at the high end of the dynamic range and so, as long as I've not blown the highlights (not really an issue when the source is film) there is plenty of scope for opening the contrast with curves or equivalent.

Here are the steps I took with this particular image (mostly working in Lightzone, my preferred editor):

Slight colour & white balance adjustment - there as quite a blue cast to the whole sky, which didn't quite work for me
Increase the contrast in 2 steps: first with a Zonemapper to pull the darker regions down (as with S-curves in PS) and then a small amount, large radius USM (for micro contrast) - here I used A.R.T. 20:100:0.
Finally, a slight lightening of the 2 dark areas on either side of the sky, to stop the dark over-powering the whole thing.

The tops of the hills visible here have had no adjustments yet.

Once done, I also took a single pass B&W filter, to see in monchrome will work. In general, I pick lack and white for images that are largely about tonal variation rather than strong colours. this is a candidate. Here's the result before dodging and burning:


Finally, a tip for large images in Lightzone. Those who use LZ regularly will probably know that it's not too great with large images (100MB+) so a 300MB 16-bit LF file is going to make it struggle. To help it cope I use the crop tool to isolate the part I'm working on (hence the crops in these samples), or even a section of that part (say just the right hand side of the sky). that cuts down the size of the working file. Once I'm happy, I disable all the aadjustments, reset the crop and then crop the next section. The last step will be to activate all the adjustmetns together. I just need to take care that I do occassional checks between adjacent regions for compatibility (to avoid harsh transitions). this way, LZ works well, and handles the final adjustment well. What seems to slow it down is all the intermediate work on the entire image while editting.

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