Across Llyn Gwnant towards Y Arran.
We can go many years without snow where we live and I live some 20 miles from our National Park of Snowdonia. Even then snow in Snowdonia can be a quite rare occurrence and seems to becoming more so as our planet warms. However this year, we have been lucky, depending on ones point of view, and welcomed a short period of cold weather and snow.
A major problem with snow is controlling the camera white balance. This is even more difficult where areas some areas lie in shadows and parts in sunlight. This is the derived effects from the colour temperature measured on the Kelvin scale and can normally be controlled in-camera by setting the White Balance control to “Auto” However, in extreme conditions “Auto” White Balance cannot control well. OK, one could change the setting in-camera, but I find this is fraught with difficulties. From a bright sunny day, to a dull wet day the images will have varying colour temperatures. These will be the result of colour temperatures being extremely varied and from warm to cool. As an example a hot summers day can be around 5000-5400K, a dull day however this changes to e.g. 6000-7500K. The chart below shows how this temperature can change depending on the light source.
All images are taken in the RAW format. Please click on images for a larger view.
It is very difficult to adjust the white balance within jpeg images. In fact it’s impossible to make this adjustment accurately.
LLyn Ogwen – Nikon D800E – Nikon 16-35mm f4. Colour Temperature 5000K.
The dreaded “blue” snow! This is a camera white balance problem where the focus and predominance of the frame is centred on a non snow area. Also, shaded areas which are have a warmer or colder colour temperature give a cast.
In Adobe Lightroom I have used the “Radial Filter”. This powerful tool allows me to adjust any selected part of a RAW image and also in a more restricted way a TIFF or jpeg..
A full tutorial on this procedure can be found here. Follow the module, but replace the routine in this video with adjustments for white balance. Below is a screen drag where I have adjusted a small area of the image to demonstrate the effect.
Below is the finished result where the Radial Filter has been used to control both the snow on the mountains and in the reflections.
Now for a really, really bad example!
Nikon D800E + 50mm f1.8 G.
As can be seen the colder (because it’s in the shade) area has a totally different colour temperature to the distant mountains. In fact the cast gradually reduces as a greater area is exposed to the sunlight. Firstly, I tackled the shadow foreground thus:
Adjusting the “temperature” slider I arrived at the image below. However, don’t over do it as the area will start to “brown” in colour. I also wanted to retain that the area appeared as it did, in shade. Next I dealt with the remaining cooler part of the image, the centre left hill which was not as badly affected as the foreground.
Once again I selected the part I wished to process.
This was adjusted more sensitively than the foreground and the finished adjustment is shown below.
I have bothered to do this blog as I was becoming very frustrated that the camera “auto” White Balance adjustment was just not clever enough to differentiate between the coldest and warmest areas of an image under extreme conditions. Yet another reason why Adobe Lightroom is my post processing software of choice.