The Cast Type combo box lets you choose between seven methods for removing color casts from images. Each method or cast type has its powers and weaknesses and works better on certain photos than the other. When processing very weak color casts, there is not that much difference between the different cast types. But with a medium or heavy color cast the different mechanisms of the cast types become quite obvious. Although it isn't their main purpose, you can also use the cast types to produce color casts in an image and thus create artistic effects. Additionally the Adjust Cast slider below the Cast Type combo box lets you adjust the intensity of the applied color correction.
With deactivated Precise check box ColorWasher very slightly increases the brightness of the image when correcting it. This may be a problem for images that have strong highlights. If you activate the Precise check box the original brightness of the image is retained and highlights will be treated more carefully, but render time is increased by 25%.
Normally you should keep the Cast Type combo box set to Autodetect, because Autodetect automatically switches between three different Cast Type options to achieve optimal results with most images.
If you are not satisfied with the result of Autodetect, please manually choose one of the other available cast types. Autodetect was designed to be used on photos, so if you are processing drawings, comics or screen shots, please try one of the other cast types. The most effective cast types are Standard, Green Cast and Red/Orange Cast. The other cast types can be very helpful for special cases.
The Standard option is very good for color correcting photos, so it is used for most photos if the Autodetect option is selected. It usually removes color casts very efficiently from all areas of a photo. If an area of the photo is overexposed it can mask it in many cases to make the overexposure less visible. However, it may not work that well for green, red or orange casts as well as non-photographic images. In that case please select one of the options below.
The Green Cast option can remove green color casts very efficiently. In some cases it works fine on other color casts, too. It works less well on drawings and similar artificial graphics.
The Red/Orange Cast option is well suited for removing red and orange color casts, but can also used for other color casts. Especially if the image looks as if it is oversaturated, this options is often the best. Nevertheless it may leaves a good deal of the color cast in the image if the color cast is quite strong. This is also useful if you basically like the color cast of a photo, because it intensifies the atmosphere of the photo. In such a case it can be used to only reduce the dominance of the color cast.
Standard Light is a variation of the Standard option. It keeps color casts in the shadows, which may look better on some photos.
The Special Case option tends to create more vivid colors than other cast types. It sometimes also manages to remove color casts more effectively than the other cast types, especially if the heavy casts and casts on older photos. It is also a good candidate for drawing or other non-photographic images. However, in some cases it doesn't remove color casts that effectively in dark areas and doesn't hide overexposed areas that perfectly.
If you like to correct old and faded photos, you should definitely try the Old Photo option. But even for digital photos it might produce a better result in some cases. For example, if an photo contains clean bright white tones, but nevertheless a color cast in it, it may do the best job. It also tends to reproduce skin tones more pinkish which may be preferred by some people.
In many cases, especially with digital photos, Old Photo tends to turn white areas into some old yellowed ones. If you like to turn your photo into an old looking one, don't hesitate to use Old Photo.
As its name suggests, can produce very extreme results, but in some cases it works similar to Special Case. Whereas the other cast types try to reconstruct image areas that were clipped by the color cast, the Extreme option doesn't do such a thing. That's why it may produce not so good results on several photos. It may lower contrast and create a strong antagonistic color cast.
But nevertheless it can be the only choice for some images. For example if you apply it to an image with only a slight cast, it can mask overexposed areas and restore the image effectively. Extreme may also work good on extreme color casts that suppress most of the other color in a photo.
Using the Adjust Cast slider is only necessary in very few cases. You can basically increase or reduce the intensity of the applied the color correction with it. This might be helpful when correcting a close-up shot with a limited number of hues. For such images it is often quite difficult to predict how the colors were originally. Adjusting the cast intensity helps sometimes to produce a result that matches your taste better. If you use the Auto buttons or create a sample area on the preview, the Adjust slider is automatically reset to zero.
What the Adjust Cast slider basically does is to internally change the saturation of the cast color, which is displayed on the Adjust Cast slider as well as in the Source color box on the Color tab sheet. Therefor the Adjust Cast slider won't work if the Source color box contains a gray value.
The Highlights and Shadows sliders work very similar to the Adjust Cast slider. Whereas the Adjust Cast slider adjusts the overall color correction, the Highlights and Shadows sliders adjust the color correction in the highlight or shadow areas only. This gives you much more control for fine tuning the color correction. However, using these features is only necessary for very difficult to correct photos.
If you created a sample area or clicked on an Auto button, ColorWasher calculates the cast strengths before and after the correction and displays them in the white text field at the bottom of the Cast tab sheet.
The first value called "Cast" is the measured cast strength in percent in the original image. Weak color cast as can be seen in a lot of images have a Cast value of 10% or less. They are usually not noticed by untrained eyes, although the difference can be clearly seen after removing it. According to our experiences photos with cast values below 50% (which is already a very strong cast that dominates the whole image) can be fixed very effectively. In one case we also managed to sufficiently remove a 70% red color cast although we wouldn't have believed that any color was left in the image. So we estimate that a Cast value between 50% and 75% can be fixed more or less sufficiently. Above 75% a lot of color information has been suppressed in the image. So sometimes your only chance to remove the color cast it is to convert the image to B/W by activating the B/W button.
Theoretically it is also possible that the Cast value exceeds 100% and runs up to 200%, although we can only imagine that such a color cast can be produced artificially. Such an image would be completely green or magenta. In that case you can forget about the image and can only hope to produce a B/W image with a more or less bad contrast.
The second value called "Remaining" represents the remaining cast strength in the corrected image. It should be below 1%, otherwise your correction is probably not that good. In that case please try different settings and see if you can achieve a better correction. Anyway, if you like the result and don't manage to get a better correction, you should trust more your eyes than this figure. Especially when using the Red/Orange Cast option the color correction may be sufficient, although the Remaining value is above even 20%.
The Cast and Remaining percentage values describes the deviation of the cast color from Neutral Gray. A neutral gray or white has a value of 0%. A cast color that is fully saturated has a value of 100%. The only exceptions are green and magenta. If they are fully saturated they theoretically can have a value of 200%, although that value is practically never reached. Basically the more saturated a color cast is, the stronger is it.
The third value called "Effectivity" tells you how effective the correction was. It should be near 100% or at least above 90%, otherwise the color cast wasn't removed completely.
If you use the manual controls from the Color tab to select a source color, only the first value will be displayed. ColorWasher assumes in that case that you selected the cast color manually. As it didn't detect the color cast itself, it has no means to tell you how good your color cast guess was. It can only tell you the strength of the cast that you manually selected.