DANBROOKE.COM
Webnation
On todays episode, we looked at colour correcting photos using Adobe Photoshop Elements.
Each colour picture we work with is actually a composite of 3 black and white images (representing the 3 primary colours: Red, Green and Blue) that combine to create the colours we see.
If one of the images (also called ‘Channels’) is too dark or too light it can show up as a colour cast in your picture.
Each of the primaries has an opposite secondary colour. The opposite of Red is Cyan, the opposite of Green is Magenta and the opposite of Blue is yellow.
Wednesday, May 26, 2010
Since we only have access to the Red, Green and Blue primary colours, if the colour cast you need to remove is one of these secondary colours, you need to add it’s opposite primary. For example, if your image has a strong Cyan cast, you can remove the Cyan by adding Red (since Cyan is the opposite of Red).
Elements offers several ways to correct an unwanted colour cast in your images.
In this example, the image has a strong Cyan cast (most noticeable in the white door on the right side of the image).
Under the ‘Enhance’ menu, go to ‘Adjust Color’ and choose ‘Remove Color Cast...’.
Your cursor becomes an eye dropper with a grey tip. Clicking on any part of the image that you know is supposed to be grey will remove the colour cast from the entire image. It works by making whatever corrections are necessary to turn the area you clicked on neutral (meaning it will have no colour, just pure grey) and applying those corrections to the entire image.
By clicking on the white door, it removes the Cyan cast from the door and the rest of the image is colour corrected automatically.
Now, you won’t always be lucky enough to have something neutral grey in your picture. If there’s a person in the shot, you can use Element’s ‘Adjust Color for Skin Tone...’ command. Under the ‘Enhance’ menu, go to ‘Adjust Color’ and choose ‘Adjust Color for Skin Tone...’.
A similar dialogue will pop up and this time, instead of clicking on an area you know is supposed to be grey, click on the person (an area of open skin, like a cheek, forehead or arm).
The image should be fairly closely colour balanced. You can make final adjustments using the 3 sliders: Tan, which adds or subtracts a brownish tanned colour, Blush, which adds or subtracts a reddish blush hue and Temperature, which adjusts how warm/cool the lighting looks in the image (bluer would simulate a noon sun, or a cold, crisp day and warmer (yellower or redder) would simulate a cozier, “inside by the filre” sort of look).
Click OK when you’re happy with the result.
If your picture has neither a grey area nor a person, it’s time to get out the big guns and make channel by channel colour adjustments.
Here’s an image with a strong Magenta cast. Remember that to take out a secondary colour (which Magenta is), we need to add the opposite colour. In this case, we’ll be adding Green (the opposite of Magenta). This time, under the ‘Enhance’ menu, we’ll go to ‘Adjust Lighting’ and choose ‘Levels...’.
The Levels dialogue lets us lighten or darken the colour channels individually. By choosing the Green channel and pulling the middle slider to the left, we are lightening the Green channel and adding Green to the image. This reduces the appearance of the Magenta that was making the sky look so purple. When you’re happy with the result, hit the OK button and the changes are applied.
There’s a lot more to colour correction than what we’ve gone over here, but this will certainly get you started in the right direction.
Next week, we’ll take a look at some cool colour effects, and learn how to make some Black and White conversions that put the simple ‘Grayscale’ command to shame.
Now, go practice!
