Once the first two stages of Colour Balance and checking the Key Colour patterns have been done, the next stage is to check for any particular colours that may need targeting and treated in isolation from the other colours. The first two stages were universal corections, but this stage is for handling an individual colour.
Reading the Image
In this image you should be able to see that the sky is a little bit Purple. However, the rest of the image looks to be correct. Don't worry if you can't see a problem as using the Eydropper tool from the Toolbar and the Colour palette will soon tell you the answer.
Taking a reading from the sky shows that the sky is indeed a problem as the Key Colour pattern is not correct. The Blue is too high, and the Green is too low.
However, taking a reading from the pavement in front of the building shows that the Grey is already neutral. This means that the problem is not universal but just applies to the one colour, so the Blue needs to be targeted in isolation from the the other colours.
Editing an Individual Colour
Leave the Colour palette open (it will be needed while the colour correction is being done) and open the Hue & Saturation panel.
REPEAT WARNING: The sliders on the Colour palette need to be "active", meaning that they must move while the colour correction is being done as they will tell us what to do and by how much. After the Curves panel has been opened you MUST click again on the blue sky area being measured. If you don't do this the Colour sliders will remain static.
From the Edit drop-down list, at the top of the Hue & Saturation panel, select the basic colour that needs to be worked with, in this example it is the Blues option.
There are three sliders available, but it is the Hue that needs to be altered as the sky needs to be moved from purple towards the cyan. But which direction? Left or right? The clue is in the spectrum strips at the bottom of the panel. The selected Blues have been marked out with grey strip between the two coloured ones. To the right of the grey strip are the Purples and the Magentas, whereas to the left are the lighter Blues and Cyans. Remember that sky blue is technically a Blue Cyan colour, so we need to move the slider to the left.
The sliders in the Colour palette will tell us how far to go. Move the Hue slider to the left, but watch the sliders on the Colour palette as you go. Stop when the Colour palette sliders form the correct colour pattern for the Key sky blue.
NOTE: When correcting with Levels and Curves the sliders on the Colour palette move one at a time, depending on which colour channel you are working on. But wihen using the Hue & Saturation panel the three sliders on the Colour palette will all move at once. Only move the Hue slider in small amounts otherwise you will end up with some very dramatic results.
The blue sky has been made more realistic, but by targeting the blues with the Hue & Saturation panel it has meant that all the other colours have been leaft untouched.
NOTE: This operation will shift all the sky blues, so even the reflections of the sky in the windows have been corrected. However, if there some Blue areas in the image that you did not want corrected then they would need to be dealt with separatly. This problem will be covered in an advanced colour correction course.
Finally, looking at the Colour palette again and clicking on the blue sky with the Eyedropper Tool you will see that the colour pattern is now as it should be.
What Can Go Wrong
If you forget to select the basic colour you want to work with from the Edit drop-down list, you will be using the "Master" setting which means that all the colours will be moved.
You may end up with the correct sky colour in this example, but the colour of the bricks have also been shifted.