The two screen shots shown here show two ways to change the percentage for a layer’s opacity. The first shows the way most beginners first learn. That is, to click of the right facing arrow next to the percentage to get the fly out slider. And then click on the slider to adjust the opacity.

However, if you place your cursor over the variable name; Opacity, in this case, the cursor changes to a hand with the index finger pointing and a little arrow going side to side. This is the scrubby slider. With a scrubby slider all you have to do is point at the title of what you want to change and, when the cursor changes to a scrubby slider, click and slide to the value you want.

The type tool is an example of where a scrubby slider can be used instead of a drop down menu.

Not everything you can change in Photoshop uses scrubby sliders, but by far most do. And Adobe is slowly getting around to updating the rest. For example, in CS4 they updated the Save for Web and Devices dialog to support scrubby sliders for many settings.

Give scrubby sliders a try. I think you will find them a much faster way to work.

The original is a raw file shot with the camera’s WB set to Auto. The center version was converted from the raw file using a setting of “As Shot”. And this pretty much matches the gray color of the overcast day when image was made. The other two are from the same raw file but the one on the left had a much cooler WB set and the one on the right had a much warmer WB set during conversion. These images all have a different mood to them. So you may ask, which one is correct?

When it comes to selecting a WB there are two very different strategies or approaches that can be followed:

1. Accurate: select a WB so the image is close to how you remember the scene being when you shot the image.
2. Creative: select a WB so the resulting image conveys the feeling you desire the viewer to experience.

Which approach you adopt is often driven by the intended use of the image. If it is for editorial or scientific purposes then there is a strong need for the colors in the image to closely match the colors in the original scene. And product photography almost always requires accurate reproduction of color. However, if your use is as a fine art print then a more artistic approach is appropriate.

In either case the photographer needs to disclose how the image was created. That is, they need to answer truthfully when asked it this is how the scene looked when they were there and made the image.

In Part 3 of this series we’ll look some practical examples of what WB setting to use when capturing the picture.

The shooting metadata for this image is as follows:

Fuji S2 w/80-200 @ 100mm
1/15sec @f/4 ISO 100
Matrix, Aperture Priority, Comp -1/2

The color of light is measured by it’s color temperature. Outdoors, ambient light changes color temperature throughout the day. It is warmer (yellower) before sunset and just after sunrise. In the open shade of mid-day it is cooler (bluish).

Our eyes compensate pretty quickly for different color temperatures. A piece of white paper will appear white to us when viewed in either warm or cool lighting conditions. However, the sensor in our cameras, left on its own,  is not so lucky. A picture of a piece of white paper taken in open shade will render quite bluish; while another picture of the same piece of white paper, taken near sunset, will be rendered yellowish.

White Balance (WB) is the tool that we use to tell the camera what the color temperature is of the light hitting our subject. If we have warm light hitting our subject, that piece of white paper will be rendered as white if we set the camera’s white balance to warm light. So if the camera’s WB setting matches the color temperature of the light hitting the subject; white, and all other colors, will be rendered correctly. However; if the white balance setting does not match the color temperature of the light hitting our subject, our photo will have distinct a color cast.

If we take a picture in mid-day sun light with the camera’s white balance set to Tungsten the resulting image will have a blue color cast. That is because the tungsten WB is telling the camera that yellow light is falling on our subject. And the camera will compensate by making the image more blue to override the yellow in the ambient light.

Likewise, we can emulate the use of a warming filter with film by using a white balance setting of cloudy. The cloudy WB tell the camera that blue light is hitting the subject so the camera adds yellow to compensate. The resulting image will have a warm color cast.

The top image was taken with the WB set to Auto and renders the color temperature pretty close to the way it was on this winter afternoon just before the sun set. The bottom picture is the same image taken with the WB set to tungsten.  Note the distinctive blue color cast the image has. Even though these two images were made at the same time and the camera was not moved between exposures, the emotional content of these two images are quite different.

In summary, we photographers can use white balance to accurately represent colors or we can use it to cause our images to be rendered with a color cast. So which is correct? We’ll discuss that next time.

For those interested, here is the shooting metadata. It is the same for both images except that, as explained above, the top images was shot with WB set to Auto and the lower image was shot with the WB set Tungsten:

Fuji S2 w/ 12mm
1/20sec @ f/11, ISO 100
Matrix, Aperture Priority, Comp +1/2

But before I can explain them you need to have some background info.

Every physical device that outputs color images (or inputs color images, like cameras and scanners, for that matter) represents color differently and can output only a limited range of colors. The range of colors that a device can output is call its color gamut. So our monitor has one color gamut and our printer will have a different range of colors, or gamut, that it can output.

 As it turns out our monitors can display a larger range of colors than our printers can. That is a monitor has a larger gamut that a printer. So when we print an image there are some colors that we see on the monitor that the printer cannot reproduce. Those colors that can not be reproduced are referred to as being out-of-gamut.

So what should the printer do with those out-of-gamut colors? One option would be for the printer to not print anything for the out-of gamut colors but that would make a rather bad print. Rendering intents are algorithms used to determine how out-of-gamut colors are mapped to in gamut colors while maintaining a reasonably good-looking print.

We’ll talk about a couple of options for Rendering Intent next time.

I started to make my first post a factual post but since this is a photo blog I thought it would be better to start off with an image post. I decided to start with one of my favorites from a recent trip to Death Valley National Park. There were many photo opportunities in DV but I’d like to give you the back story for just one image, the thumbnail for my Death Valley Sand Gallery. 

There are several sand dune areas is Death Valley. However, only two of them are “easily” accessible. The first, and most visited because it is quite accessible, is Mesquite Flats near Stovepipe Wells. It is accessible right off of the main road that runs through the park, Rt 190.  The best time to photograph sand dunes is during the golden hours, just after sunrise and before sunset. The dunes run north-south so when the sun is low one side is lit with warm light while the other is in shadow. And any time the light is at a low angle textures will be accentuated, like ripples in the sand. Most of the images from Mesquite are a study of the highlight and shadow side of individual dunes.

The second dunes, Eureka Dunes, requires some effort to get to, including driving a couple of hours on unimproved gravel roads. These dunes are MUCH taller that those at Mesquite Flats. But after getting there I did not find the location to be particularly photogenic. I think, at least in part, is that the dunes run east-west so the setting sun light hit both sides of each dune evenly resulting in relatively flat light even though the sun was low in the sky.  However, I did make one image that I particularly like, the one above. Here the sun was in the process of setting behind the Saline Range. This put the dune I was on in shadow (cool light) while the front side of the main dune, in the background, was bathed in warm light. This only last a few seconds.

The second dunes, Eureka Dunes, requires some effort to get to, including driving a couple of hours on unimproved gravel roads. These dunes are MUCH taller that those at Mesquite Flats. But after getting there I did not find the location to be particularly photogenic. I think, at least in part, is that the dunes run east-west so the setting sun light hits both sides of each dune evenly resulting in relatively flat light even though the sun was low in the sky.  However, I did make one image that I particularly like, the one above. Here the sun was in the process of setting behind the Saline Range. This put the dune I was on in shadow (cool light) while the front side of the main dune, in the background, was bathed in warm light. This only last a few seconds.

Here is the camera shooting metadata for this image: 

D200 w/ 24-70 f2.8
24 mm, 1/30 sec @ f/6.3, ISO 100
Matrix Metering, Aperture Priority, Compensation +2/3

The About page explains what this site is about and how I plan on using this blog so I will not repeat that here.

Check back periodically for new image posts, image processing and workflow tips, and informative articles.