Using the EyeDroppers in Photoshop

Article and Photography by Ron Bigelow

www.ronbigelow.com

Photoshop CS2 Used in this Tutorial

Figure 1: Levels

The Eyedroppers are very popular tools. They can be found in both the Levels dialogue box (see Figure 1) and the Curves dialogue box (see Figure 2). As can be seen in these Figures, there are three Eyedroppers. The left Eyedropper is the Black Eyedropper and is used to set the black point or shadow values. The right Eyedropper is the White Eyedropper and is used to set the white point or highlight values. The middle Eyedropper is the Gray Eyedropper and is used to set the midtones in the image.

While the Eyedroppers are very useful, there is a problem. The proper use of these tools requires a bit of sophistication on the part of the photographer that is using them. The issue is that the Eyedroppers are not always the best tool for the job. This is because the Eyedroppers can easily cause color shifts in an image to which they are applied. In some cases, this is desired. In fact, because the Eyedroppers can create color shifts, they are frequently used to correct colorcasts. On the other hand, improper use of the Eyedroppers can induce unwanted color shifts in images.

Figure 2: Curves

The reason that I wrote this article is that I see some photographers improperly using the Eyedroppers. Thus, the purpose of this article is to look at the Eyedroppers and how they affect an image with the intention of setting some guidelines for how the Eyedroppers should be used and when another approach should be chosen. It is assumed that the reader has a working knowledge of the Eyedroppers. For those that want a review of these tools, the tools are covered in my series on Levels (for more information on the use of the Eyedroppers with Levels see, Levels -- Part II) and Curves (for more information on the use of the Eyedroppers with Curves, see Curves -- Part III).

Images with No Color Cast

Figure 3: Image that Needs Shadows and Highlights Set

Figure 3 shows an image that has no colorcast. However, the image is a bit flat. This can also be seen in the Histogram in Figure 4. The figure shows tonal gaps at both ends of the Histogram. This indicates that there are few true whites or blacks in the image (for more information on reading Histograms, see Histograms -- Part I). This can be corrected by setting the shadow and highlight values with the eyedroppers. However, since this image has no colorcast, it is critical that no colorcast be created when the eyedroppers are used.

Figure 4: Histogram
Figure 5: Info Palette
For this example, the Info palette (choose Window/Info) will be used in conjunction with Levels (choose Layer/New Adjustment Layer/Levels) to set the shadow and highlight values The Info palette is shown in Figure 5, and Levels is shown in Figure 6.
Figure 6: Levels
Figure 7: Color Picker Dialog Box for Selecting Target Highlight Color
To begin the process, the Color Picker is launched by double clicking the White Eyedropper. The Color Picker (see Figure 7) is used to set the highlight values. These values will then be assigned to whatever point is clicked with the White Eyedropper. The values are set by entering the values directly into the R, G, and B boxes. The values should be set between about 245 and 254. The higher the value, the lighter the highlights will be. As long as the same value is entered into each of the three boxes (e.g., 250 in this case), the highlight values will be neutral. Clicking OK closes the Color Picker.
Figure 8: Color Picker Dialog Box for Selecting Target Shadow Color
Next, the Color Picker is launched again by double clicking the Black Eyedropper. The Color Picker (see Figure 8) is now used to set the shadow values. These values will then be assigned to whatever point is clicked with the Black Eyedropper. The values are set by entering the values directly into the R, G, and B boxes. The values should be set between about 2 and 8. The lower the value, the darker the shadows will be. As long as the same value is entered into each of the three boxes (e.g., 8 in this case), the shadow values will be neutral. Clicking OK closes the Color Picker.
Figure 9: Location for Highlights

To set the highlight values, the White Eyedropper is simply moved around the light areas of the image (the curser turns into the White Eyedropper as it is moved over the image). As the White Eyedropper is moved around, the Info palette indicates the tonal values of the location directly below the White Eyedropper. For the setting of the highlight values, it is desired to find a position that has very high tonal values but still holds detail. Since this image has no colorcast, it is necessary for the position to be fairly neutral.

Figure 9 shows the location selected for setting the highlights (a color sampler had previously been placed at this location). Figure 10 shows the Info palette reading for this location.

Figure 10: Info Palette Reading for the Highlights
The Info palette shows that the selected location is almost perfectly neutral. Also, moving the White Eyedropper around shows that there is detail in this area. The White Eyedropper is clicked at this location.
Figure 11: Layers Palette After Highlight Values Set
Figure 11 shows the Layers palette after the highlight values were set.
Figure 12: Info Palette After Highlight Values Set
Figure 12 shows the Info palette after the highlight values were set. As can be seen, the highlights are neutral. Since the location selected for setting the highlight values was fairly neutral before the highlight values were set and is now neutral after they were set, no significant shift in color has occurred. Thus, no colorcast has been created in the image.
Figure 13: Location for Shadows

To set the shadow values, the Black Eyedropper is simply moved around the dark areas of the image (the curser turns into the Black Eyedropper as it is moved over the image). As the Black Eyedropper is moved around, the Info palette indicates the tonal values of the location directly below the Black Eyedropper. For the setting of the shadow values, it is desired to find a position that has very low tonal values but still holds detail. Since this image has no colorcast, it is necessary for the position to be fairly neutral.

Figure 13 shows the location selected for setting the shadows (a color sampler had previously been placed at this location). Figure 14 shows the Info palette reading for this location.

Figure 14: Info Palette Reading for the Shadows

Again, the Info palette shows that the selected location is almost perfectly neutral, and moving the Black Eyedropper around shows that there is detail in this area. The Black Eyedropper is clicked at this location.

Moving the Black Eyedropper around shows that this image has darker areas than this location (some of the values in these darker areas are around 24). However, these darker areas are not neutral. Because of this, the values in the Color Picker where set at 8, 8, 8, rather than a lower number, so that the darker shadows would not be clipped.

Figure 15: Levels Palette After Shadow Values Set
Figure 15 shows the Levels palette after the Shadow values were set.
Figure 16: Info Palette After Shadow Values Set
Figure 16 shows the Info palette after the Shadow values were set. As can be seen, the shadows are neutral. Since the location selected for setting the shadow values was fairly neutral before the shadow values were set and is now neutral after they were set, no significant shift in color has occurred. Thus, no colorcast has been created in the image. Figures 17 and 18 show the image before and after the highlight and shadow values were set.
Figure 17: Image Before Highlight and Shadow Values Set
Figure 18: Image After Highlight and Shadow Values Set
Figures 17 and 18 show that setting the highlight and shadow values has slightly increased the contrast of the image. This can be best seen in the flowing water, which is brighter in the second image. Furthermore, it can be seen that no color shift has occurred.
Figure 19: Info Palette Reading for the Highlights
However, if a non-neutral location is selected for setting the highlights or shadows, a colorcast will occur. As an example, Figure 19 shows a non-neutral highlight location for the current image. Figures 20 and 21 show how choosing this location to set the highlights causes a color shift. Figure 20 shows the image when the neutral location was used to set the highlights. Figure 21 shows the image when the non-neutral location was used. Looking closely at the water in Figure 21 shows a slight bluish cast. This shows that the image has picked up a colorcast.
Figure 20: Image After Highlight Values Set With Neutral Highlight Location
Figure 21: Image After Highlight Values Set With Non-Neutral Highlight Location

First Conclusion

This brings us to the first conclusion. A photographer should use the White and Black Eyedroppers, with neutral images, only if he is very careful to select neutral locations for setting the highlights and shadows. If the photographer does not want to be meticulous in selecting these locations, he should choose another method of setting the highlights and shadows (other methods are covered in the series on Levels and Curves).

Images with a Color Cast

Figure 22: Image with a Color Cast that Needs Shadows and Highlights Set

The Eyedroppers can be used to set the highlights and shadows and to correct a colorcast at the same time. However, there is a limitation to this approach. It can be used only with images that have highlights and shadows that should be neutral after the application of the Eyedroppers.

Figure 22 shows an image that has a blue colorcast. This image is a good candidate for using the Eyedroppers to correct the colorcast. This is because the highlights in the flowing water should be a clean white. Similarly, the shadows should have no tint.

Figure 23: Highlight and Shadow Locations Selected
Figure 23 shows the locations that were chosen for setting the highlights and shadows.
Figure 24: Info Palette Reading for the Highlights
Figure 24 shows the values of the location where the highlights will be set. It can be seen that this location has a large amount of blue.
Figure 25: Info Palette Reading for the Shadows

Figure 25 shows the values of the location where the shadows will be set. It can be seen that this location also has a large amount of blue.

The highlight and shadow values are now set using the same procedure used in the example above. Figure 26 and 27 show the image before and after the highlights and shadows were set.

Figure 26: Image Before Highlight and Shadow Values Set
Figure 27: Image After Highlight and Shadow Values Set
Figure 27 shows that the colorcast has been removed.
Figure 28: Image that will not Work Well with Eyedroppers
As mentioned above, not all images work well with the eyedroppers. Figure 28 is one example. This image has a green cast. While this might not, at first, be noticeable because the foliage is supposed to be green, the green cast can be seen in the dirt trail. While this image needs some color correction, the Eyedroppers are not the best choice to remove the colorcast since there are no highlights in the image that should be neutral white after the color correction.

Second Conclusion

Thus, we come to the second conclusion. A photographer should use the White and Black Eyedroppers to set the highlight and shadow values, with images that have a colorcast, only when the image has highlights and shadows that should be neutral in the final image.

Overall Conclusion

The Eyedroppers are a great tool, but only for photographers that are willing to study their images to determine the color nature of the highlights and shadows and to customize the use of the Eyedroppers to the specific needs of each image. In other words, a photographer can not blindly apply the eyedroppers to all images in the same way and expect to get good results. The use of the Eyedroppers must be customized for each image.

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