Fixing Color Cast with the Levels Tool (Xara Xtreme Pro only)

Xara Xtreme Pro offers the ability to adjust the color casts or color tints of photos, thanks to the powerful Levels tool.

Here are two examples of photos with a really bad blue cast. This was the result of using the wrong white balance setting on the camera. The photos previous to these were taken inside and had the white balance set for incandescent bulbs. The result is that normal daylight photos come out with this really strong blue cast.



The versions on the right are a result of using the Level tool ability to adjust the color cast. It's unusual to be able to restore images completely, and these examples are not perfect but do show very significantly improved images.

To make adjustments like this, open the photo in the Xara Picture Editor by just double clicking on the photo (the easiest way to open a photo in Xara Xtreme is just to drop it onto the Xtreme window from your Windows File Explorer), and then select the Levels tool indicated.



This is the histogram of the snow picture. As you can see from the histogram, and the picture itself, it's a bit washed out, and lacking contrast. The red histogram shows no really dark color or really light colors.





The Levels tool contains three icons for setting the black, grey and white points, as shown. To set the black, gray or white points just click one of these icons, and now click on a black, gray or white part of the image. The program re-calculates the histogram, and most importantly, the color mix, to adjust the clicked on part to be black, grey or white.

So, let's go through this process step-by-step with the above image.

First I want to set the white point, so I select the right button, and then click on the whitest part of the image. In this case I've marked where I think the whitest and blackest parts of the image are.





And straight away you can see not only has the histogram improved to show a better spread of shades, but the image has improved as well.

The last stage is to set the gray point. This is the most important one that influences the color tint the most. Select the center 'pick gray' button and then try to click on any part of the image that is meant to be gray. Perhaps surprisingly, snow is not gray, and clicking on some dull part of the snow over-compensates and results in an image like this:





This is still better than the original but the gray stone wall is actually a better point to set the gray point. The second example below shows where I clicked and the resultant photo that resulted from this. You can see that it's made the stone, where I clicked, to be truly gray, and thus balanced out the whole color cast of the image. Compare it with the original and you can see the dramatic improvement.



More Advanced Control

If you want to further adjust the colors you can use the Channel drop down at the top of the Levels Dialog to select either the red, green or blue channel. You can then use the same slider controls to adjust just that color channel. This is actually quite a powerful way of altering colors if you understand it.

So, for example, if you want to make your picture redder you can select the red channel and then drag the gray-point slider to the right. This is actually adjusting the gamma of the red channel. If you drag it to the left, this has the effect of decreasing the red, which is the same as increasing the cyan or light blue tint on the image. So the rules for altering colors this way go like this (dragging the middle slider control):

Red Channel---->Increase red tint<-----Increase Cyan tint
Green Channel---->Increase green tint<-----Increase magenta tint
Blue Channel---->Increase blue tint<-----Increase yellow tint

Of course you can use combinations, increase one color while reducing another to get even more subtle combinations. And you can also use the black and white point controls to provide even further control over the color tinting.

Summary:

To adjust the color cast of your photo, use the Levels tool of Xara Picture Editor (only available in Xara Xtreme Pro) and use the three buttons to set the black, gray and white points by clicking on the darkest, mid-gray, and whitest points on your photo. Selecting the pick gray button and then clicking on any part of the picture that should be gray is the quickest way to correct the color tint of a photo.

Tip: All Xara Picture Editor edits are non-destructive. That is, they do not affect the original photo. You can edit the values or reset them to restore your original image.

You can find out more about the Levels Tool in this month's other tutorial.