Lightroom Tips & Tricks - How to remove colour casts
Removing Unwanted Colour Casts
Welcome to the first in an on-going series of blog posts whereby I will discussing and demonstrating various Tips & Tricks that can be performed within Adobe Lightroom when processing and developing your RAW files. You will notice that I explicitly mentioned RAW files as that file format is simply the best format that you can use in order to get the best out of your images. See my other blog post here for reasons why!
To start us off in this new series of blog posts focusing on Lightroom Tips & Tricks, as promised in my last blog post How colour temperature and white balance impacts landscape photography we will look at how easy it is to remove unwanted colour casts from your RAW files when processing them in Lightroom.
The Problem
It is actually more common than you may think for your images to contain colour casts. When shooting indoors and using flash your images will contain a colour cast if the white balance and colour temperature is not set as needed. When you review the image on the back of your LCD screen or back at your computer you will recognize and see the colour cast very quickly as it will be very obvious when looking at the skin tones of the model in your image.
The same applies to shooting outdoors at certain times of the day when your white balance is incorrectly set. When reviewing your image you will quickly realize that there is an overall colour cast present throughout the scene and of course the resulting image does not resemble the colours and conditions that were present in the scene at the time when you were shooting it.
For any Landscape Photographer who ventures into the world of Long Exposure Photography and using filters, you will quickly learn that all filters will produce a colour cast of some description, with some being much worse culprits than others!
The strength of the colour cast is determined by (1) the brand of filter you were using and (2) the type and density of the filter you were using. Naturally any filter which does not have a Neutral Density will of course introduce a colour cast and this is totally expected. Obviously if the filter is a coloured filter, then that filter is going to introduce that colour into the image. This is perfectly normal, expected and desired because the photographer has made a conscious decision to use said coloured filter in order to obtain a particular end result in their image.
“In photography and optics, a neutral density filter or ND filter is a filter that reduces or modifies the intensity of all wavelengths or colors of light equally, giving no changes in hue of color rendition. It can be a colorless (clear) or grey filter.”
When photographers make the choice to use Neutral Density it is for the very purpose of NOT introducing a colour cast into their image. And this is where the problem starts. Some Neutral Density filters produce very obvious and bad colour casts. While these colour casts might actually add a positive result to the image around 5% of the time, for the other 95% these colour casts are definitely unwanted and can be down right annoying at times.
10 stop ND filters such as the Lee Big Stopper are known for their ability to offer the photographer long exposure times even during the middle of the day! However, they come with a price and I am not talking about the €120 a single filter will cost you, I am referring to the fact that they introduce a big ugly blue colour cast, as can be seen in the below image.
This is the RAW file of an image that was captured during the afternoon a summers day at Rocky Bay, County Cork, Ireland. As you can see the image contains a very strong blue colour cast throughout the scene and this is due to the Lee Big Stopper (10 stop ND filter)
The Solution
While removing these unwanted colour casts can be somewhat of a painful process when working with JPEG files; which have already been processed by your camera and embedded with the white balance and colour temperature data having already been set, it is actually rather easy to remove these colour casts when processing your RAW files in Lightroom.
The basic panel in the Develop Module within Lightroom 6
The Basic panel within the Develop Module in Lightroom offers you several means of removing this colour cast.
- You can use the White Balance Presets (highlighted in green) to see if you can clear away the colour cast with one of the predefined white balance values.
- Alternatively, you can try playing around with Temp and Tint sliders (highlighted in yellow) in order to get the image closer to the expected colour tonal values based on what you remember from the time when you were shooting the image.
- But the most simplest and quickest method is to use the White Balance Selector tool (highlighted in red) that looks like the Eye Dropper tool icon that everyone who has used Photoshop would be familiar with.
The best thing about this tool is that it is actually really easy to use.
Surprisingly this tool often goes unnoticed and overlooked by many Lightroom users. I think despite the size of the icon, it can kind of blend into the grey background somewhat. Plus, the colourful sliders are probably way more attractive to the user and probably commands more of their attention.
I for one can now safely and confidentially confess that I was one such user. When I look back on my photography journey over the past few years, I constantly cringe at just how long it took for me to discover this Lightroom gem!
I can honestly say that learning to use the White Balance selector tool effectively will be one of the best things that you will ever add into your armory of Post-Processing skills.
Simple as 1, 2 and 3!
Here is a quick overview of how you can use this tool in 3 easy steps.
- Click on the White Balance selector tool and ensure that the "Auto Dismiss" option is deselected.
- Hover it over a section within the image which you expect to be close to a neutral grey. This is called selecting your Neutral Target. If you don’t get the right correction the first time, click again on a different area of the image until you get an adjustment that looks correct to you.
Notice as you hold the White Balance Selector over the image that the Loupe shows a gird of pixels around the area you have the mouse held over and it also shows the relative percentages of red, green and blue in the pixels over which the mouse is hovering. Where the color in an image should be neutral grey, these values should be the same and if they are not, there is a color cast.
You will know that you have removed the colour cast when the relative percentages of red, green and blue in the pixels over which the mouse is hovering are equal. When you have a result you like, either return the White Balance Selector to its position in the Basic panel or press Escape.
Placing the White Balance selector tool over a area of clouds that I expected to be grey. Notice that the relative percentages are different. This means there is a colour cast.
After clicking on a particular section of the image that I expected to be grey, the image has now changed and the colour cast has been removed. This is confirmed by the fact that relative percentages are now the same value.
As you can see, it is really is that simple. Of course there will always be times where further tweaking of the colours will be required after this process. After all, this process is simply removing the colour cast, it is not enhancing or processing the colour tones in the way that you will probably need and want to process them.
A job well done!
Well hopefully now at this stage you have seen how easy this tool is to use and how effective it can be with respect to speeding up your Lightroom processing workflow.
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