Category: Ask Tim Grey

Today’s Question: How do you show dust spots in Lightroom or Photoshop so you can correct it?

Tim’s Quick Answer: In Lightroom it is relatively easy to locate dust spots in your photos by using the “Visualize Spots” option associated with the Spot Removal tool. In Photoshop I generally use an exaggerated adjustment using Curves to help locate dust spots.

More Detail: The Visualize Spots option provides a tremendous advantage for locating dust spots in Lightroom. Once you have selected the Spot Removal tool, you’ll find the Visualize Spots checkbox on the toolbar below the preview image. If the toolbar isn’t present, simply press “T” on the keyboard to enable the toolbar.

With the Visualize Spots checkbox turned on, the image will change to a black and white preview, highlighting contrast edges within the photo. The slider to the right of the Visualize Spots allows you to adjust the threshold for that display. While I generally find that spots are easiest to see when the slider is all the way to the right, I highly recommend dragging the slider left and right through the full range for a more complete evaluation of the image.

Note that you can leave the Visualize Spots checkbox turned on while performing cleanup work on the image. However, you’ll want to be sure to turn off the Visualize Checkbox periodically to evaluate the results you’re achieving are blending in well with the surrounding areas of the photo.

In Photoshop there isn’t an equivalent to the Visualize Spots (although this option is available in Adobe Camera Raw). Therefore, when working in Photoshop I will use an exaggerated Curves adjustment to help find any dust spots present in the image. I’ll simply add a new Curves adjustment layer to be used for this purpose, and then drag the curve up and down for an extreme adjustment. This can help make dust spots easier to see.

As long as the image cleanup tool you’re using ignores the effect of adjustment layers, you can leave this Curves adjustment layer enabled while you perform your cleanup work. For example, the Spot Healing Brush tool this behavior is always active, so you can leave the Curves adjustment turned on without worrying about an impact on your cleanup work. For the Healing Brush and Clone Stamp tools there is a setting on the Options bar that will cause these tools to ignore the effect of adjustment layers. The button for this option is the same basic icon as the half-black and half-white circle icon for the button used to add an adjustment layer.

In addition to using these view options to help you locate dust spots in an image, it is also important to zoom in a little bit to make it easier to see the dust spots, and to review all areas of the photo. I recommend taking a somewhat methodical approach to that review, to make sure you locate all dust spots in the photo so you can remove those dust spots and ensure a “clean” image.

Today’s Question: To achieve focus is zooming in on “Live View” and focusing better than zooming in with the lens itself to focus?

Tim’s Quick Answer: With most zoom lenses if you change the zoom setting you do not maintain focus. So if you zoom in to set focus, then zoom out again, the image would no longer be in focus. When zooming in using the Live View display rather than the lens itself, you don’t have to worry about this issue.

More Detail: There are some zoom lenses that will maintain focus when you zoom. Those lenses are referred to as being “parfocal”, but they are in the minority of zoom lenses. Note that in professional video production it is indeed a common practice to zoom in with the lens to establish focus, and then zoom out again. But that only works with zoom lenses designed to maintain focus when the zoom setting is changed.

If you know that one of the zoom lenses you are using is parfocal, you can certainly zoom in using the lens to establish focus. When in doubt it is best to leave the zoom setting on the lens fixed, and zoom in with the Live View display to establish manual focus (or to confirm accurate focus). And frankly, I would feel completely comfortable trusting that a lens that is parfocal will really perform such that there isn’t any change in focus when the zoom setting is changed, so to me Live View is always the best approach.

It is worth noting that the Live View display will also generally enable an exposure simulation, so that even when the scene is relatively dark you’ll be able to see a reasonable (though possibly noisy) preview on the camera’s LCD display. And keep in mind that if you enable the depth of field preview on your camera (if so equipped), the combination of that depth of field preview and the exposure preview can be tremendously helpful for evaluating your overall camera settings.

Today’s Question: Do I understand it correctly that you’d move the Levels adjustment slider from 0 to 15 in your Print Target example before pressing “Print” [to compensate for a lack of shadow detail in the print]?

Tim’s Quick Answer: Yes, if testing has demonstrated that my prints are not rendering full shadow detail all the way down to a full black value, I would apply an adjustment using Levels before printing my photos. It is important to note that this would relate to the “Output Levels” adjustment, not the black point adjustment found directly below the histogram in the Levels dialog.

More Detail: The issue here is that in many cases a print will not reflect the full level of shadow detail as actually exists in the image file. Instead, that shadow gets “blocked up”, similar to the way shadow detail gets clipped in an exposure that is too dark. You can compensate for this issue by essentially brightening the value of black, causing all neighboring tonal values to be brightened up accordingly.

The key is to determine the optimal adjustment to apply. This can be done using a print target image that contains a series of dark shades toward black (and a series of bright shades toward white). You can print the test image using your normal printing workflow, and then evaluate the results under a very bright light source.

When you determine which tonal value is the first where you can see a visible difference between the two values, the darker of those two represents your target black point for the print. So in Photoshop you can apply a Levels adjustment just before printing, setting the Output Levels value for black to the value you determined from the test print.

In Lightroom you could use the Tone Curve to apply the same basic adjustment. Be sure you are in the Point Curve mode for the Tone Curve adjustment, rather than the Parametric option. In other words, make sure you don’t see the sliders for Highlights, Lights, Darks, and Shadows below the curve, clicking the button at the bottom-right of the Tone Curve section if you need to switch modes. Then drag the black end point of the curve (the bottom-left end of the diagonal line) upward. The adjustment value will be shown as a percentage in the top-left of the curve area while you are dragging, so you’ll need to convert the tonal level value to a percentage by dividing the value by 256 first.

You can obtain a print target image I use for evaluating black and white levels in my prints by following this link:

http://timgrey.me/printtarget

Today’s Question: In a recent Ask Tim Grey you said you used Image Capture to transfer images from your iPhone to Lightroom. My question: what is the procedure you use to accomplish this transfer?

Tim’s Quick Answer: My approach is to first download photos from my iPhone to a folder on my computer. When the download is complete, and before I use the option to delete all photos from the phone, I import the downloaded photos into Lightroom using the Copy option in the Import dialog to copy the images to my normal storage location. At that point I delete all of the photos from the iPhone.

More Detail: Admittedly, this workflow is a bit complicated. The key issue is that I want to treat my iPhone as a “regular” camera. The problem is that the iPhone doesn’t include an easy way to delete all images from the phone, unlike a camera that includes the ability to format the digital media card. I would love it if Adobe added a “Delete After Import” option so I could simply use the Import feature, but since the vast majority of cameras include a format feature, this isn’t exactly a high priority feature for Adobe to work on.

The lack of an easy “delete all photos” feature for the iPhone has caused me to create a workaround workflow. I start by downloading the photos from my iPhone to what is essentially a temporary folder on my desktop. I use the Image Capture application included with the Macintosh operating system, in large part because Adobe Bridge for Macintosh has recently had some issues with the iPhone. Windows users can still use the Photo Downloader feature in Adobe Bridge, or use the “Import Pictures and Videos” feature. Both of these options for Windows users include an option to delete all photos from the iPhone after the photos have been successfully copied.

Once the download of my photos is complete, I will import the new photos into Lightroom. I use the Copy option in the Import dialog to copy all of the photos to a new folder in my normal storage location for photos. In theory I could download the photos to my primary storage location for photos right from the start. However, my preference is to take this more structured approach, in part to help make sure I never forget to import the new photos into Lightroom. The folder of photos on my desktop helps remind me to import the photos, and then serves as a backup copy of the images as well.

After the photos have been imported into Lightroom, I will erase the images from my iPhone. My approach is to keep the iPhone connected to the computer when the download is complete, and to import the photos into Lightroom before deleting photos from the phone, so I retain a backup copy at all times.

And of course, I will then perform a backup of my primary photos storage location, so I have yet another copy of my latest captures, before deleting the “temporary” download folder on my desktop.

Today’s Question: With the Independence Day holiday approaching [in the US], could you provide some tips for photographing fireworks?

Tim’s Quick Answer: In my mind the most important consideration for great fireworks photography is the composition. Try to find a position where you can have something interesting in the foreground. That and proper exposure are the most important factors to keep in mind.

More Detail: To be sure, a “simple” fireworks photo that only includes the burst of fireworks in a nearly black sky can be interesting. But to me it is much more interesting to create a composition with a strong foreground subject. That could be an interesting architectural element such as a bridge or city skyline, or simply people in the foreground enjoying the show, for example.

Obviously you’ll need to ensure a proper exposure, but frankly this is generally somewhat straightforward with firework photography. I recommend that you start with the minimum ISO setting for your camera, a lens aperture of about f/8, and an exposure of around 5 to 10 seconds. Evaluate your initial results, and adjust your exposure settings from there.

Naturally a long exposure will produce streaks of light in your photos from the fireworks display. In addition, it will provide the potential for multiple bursts within the same exposure, creating a more dramatic result.

I often hear the advice to set the focus at infinity. However, that has the potential to result in a scene that is not in crisp focus. Even with a wide-angle lens, sometimes setting the focus at infinity may cause the overall scene (or at least the foreground) to be out of focus. Try using the live view display and zooming in on a foreground element to establish focus manually. It will likely be challenging under dark conditions, but it will help ensure the best photos.

Most of all have fun and try to think creatively. The more you can do to make your fireworks photos stand out from all the rest, the more interesting those photos will be.

Today’s Question: In your book “Color Confidence,” you recommended setting the target black and white output values (especially the black value) prior to printing in order to compensate for printers that are unable to produce discrete shades of black throughout the complete tonal range available in the digital image. Do you find that this approach is still necessary with the newest inkjet printers?

Tim’s Quick Answer: Yes, I do find that this approach of compensating for a lack of shadow detail is still necessary, even with many of the latest printers.

More Detail: With the vast majority of printers I find that no compensation is needed for the white point. In other words, when producing a print with most printers using just about any paper, you are able to see a difference between pure white (no ink on the paper) and the next darker shade of white.

With dark shadow values, I still find that many printers have a difficult time producing distinct shades of black. In other words, the darkest black appears the same as one shade lighter, so you can’t actually see a difference between the two. In other words, shadow details get lost in a sea of black.

In fact, I have often found that when photographers complain about a print that is too dark, what they’re really seeing is a print with a lack of shadow detail that appears too dark as a result. Opening up those shadow details can help tremendously.

I generally prefer to take a somewhat systematic approach to evaluating the capabilities of a given printer, ink, and paper combination, so that I can apply a compensation adjustment that is most appropriate to that combination. This involves printing a series of tonal values in a “ramp” for both the black point and the white point, so that I can then determine the appropriate compensation.

If you’d like to download a copy of the print target that I use for evaluating prints, you can get access by following this link:

http://timgrey.me/printtarget

Today’s Question: In the Lightroom develop module what are the functional differences between Highlights, Shadows, Whites, and Blacks in the Basic section, and a similar set of variables in the Tone Curve section?

Tim’s Quick Answer: These controls in Lightroom are all focused on tonal adjustments, but they all focus on tonal ranges in different ways. There is certainly some overlap between the Basic controls and the Tone Curve controls, but there are unique aspects to consider as well.

More Detail: Each of the individual sliders for the Basic and the Tone Curve adjustments focus on a range of tonal values in the image. That isn’t to say that a given adjustment focuses exclusively on a specific tonal range without affecting pixels that fall outside that tonal range. Rather, you can think of each adjustment control as emphasizing its effect on a specific range of tonal values.

I prefer to think of the Whites and Blacks sliders as being used to establish the white and black point in the image, respectively, though the adjustment goes beyond just affecting the “end points” of tonality.

I think of the Highlights and Shadows controls as being primarily focused on how much detail versus contrast I want to present in the image (though again, the reality of the adjustment is a bit more complicated than that).

The Tone Curve adjustment is a bit more unique. In the “parametric” mode where you have the Highlights, Lights, Darks, and Shadows sliders, the concept is very similar to the Highlights and Shadows sliders in the Basic section. Your adjustment is emphasized for a given tonal range as noted by the name of each slider.

However, the Tone Curve adjustment also enables you to essentially redefine the meaning of each of those sliders, which can be done in two ways. First, you have a set of slider handles directly below the curve display, which enables you to define the extent of tonal values affected by each of the sliders. For example, you can narrow the range of tonal values that are affected by Darks so that you are really focusing the effect on a small range of the darkest tonal values in the image.

Taking things a step further, you can also work in the Point Curve mode. This allows you to go beyond the four slider controls and actually add anchor points on the curve to manipulate the shape of that curve. That, in turn, enables you to exercise greater control over your tonal adjustments for an image.

With most of my photos I find that the Whites, Blacks, Highlights, and Shadows sliders provide adequate control of overall tonality to achieve my goals for a photo. In some cases, however, I will use the Tone Curve to further refine the tonality in a photo, using the Point Curve mode. And, of course, some photographers prefer to work directly in the Tone Curve adjustment to effectively replace what they might have otherwise done with the Highlights and Shadows controls in the Basic section.

My recommendation is to experiment with all of these tonal adjustments with some of your photos to gain a better understanding of what each control does, and what approach to employing these adjustments might make the most sense for your personal workflow.

Today’s Question: While giving a presentation the other night, you turned your mouse pointer into a spotlight to highlight what you were doing in Lightroom and Photoshop. What application are you using to change your curser into a spotlight?

Tim’s Quick Answer: I use an app called “Mouseposé”, which is a Macintosh application that enables you to highlight the mouse position. Windows users can simply enable the option to “Show location of pointer when I press the CTRL key” found on the Pointer Options tab of the Mouse Properties dialog.

More Detail: The built-in option for Windows users creates an animation of red circles to show the mouse pointer position whenever you press the Ctrl key. This is a handy option that you can enable when you will be presenting to others and then disable when you’re not presenting.

For Macintosh users I highly recommend the Mouseposé application, which is what I use. This app is available in the Apple App Store. With the Mouseposé application running you can use a keyboard shortcut to enable or disable the display. When the display is enabled, your entire screen will be darkened except for a circular area around the current position of your mouse pointer.

The effect is to shine a “spotlight” on your current mouse position, with that spotlight effect following your mouse as you move it around on the screen. I find this can be tremendously helpful for users to see exactly where you’re working within an interface when demonstrating a technique to them with a projected display.

Today’s Question: I find that I need a very delicate hand on the adjustment sliders in Lightroom. Just a touch does it. I am getting better but wonder if there is an adjustment that can be made somewhat like adjusting the speed of a mouse?

Tim’s Quick Answer: There are two options here that might help you. First, you can indeed adjust the “acceleration” setting for the mouse, which affects the speed at which the mouse moves. Second, you might want to use keyboard shortcuts to fine-tune the settings for your adjustments.

More Detail: Moving the mouse obviously results in a corresponding movement of the mouse pointer, but there is an option to adjust the sensitivity of that mouse movement. In other words, you can choose whether you want a small movement of the mouse to translate to a relatively small or large movement of the mouse pointer.

You can adjust this setting on Windows by adjusting the Mouse Speed setting under the Mouse option in the Control Panel. You can even turn off mouse acceleration altogether if you prefer. On Macintosh you can adjust the Tracking Speed setting in the Mouse section of the System Preferences dialog to achieve the same basic result.

Another great option is to use keyboard shortcuts to adjust the slider values in Lightroom. To enable this option for a given adjustment you first need to click your mouse pointer on the numeric value associated with the adjustment control you want to change.

Once the numeric value associated with a given adjustment slider is active, you can press the up arrow key on the keyboard to increase the value and the down arrow key on the keyboard to decrease the value. You can also hold the Shift key while pressing the up or down arrow key to apply a larger adjustment. With most adjustment sliders, using the Shift key in conjunction with the up or down arrow key will cause a ten-fold increase or decrease in the value compared to the normal behavior of the up and down arrow keyboard shortcut.

Personally, I prefer to have my mouse configured to be relatively sensitive, meaning that a relatively small movement causes the mouse pointer to move a relatively large distance. However, I also find that I sometimes struggle with the mouse when it comes to manipulating the adjustment sliders in Lightroom. Therefore, I’ll frequently use the up and down arrow keyboard shortcuts to fine-tune the adjustment settings when working on an image in Lightroom.

Today’s Question: Let’s say I have 3 images that I want to merge to HDR [high dynamic range] and I have made Develop Module adjustments to one or more of them. When I merge them to HDR, does the merge operation use the edited version of the images or the original unedited, versions?

Tim’s Quick Answer: If you use Lightroom to create the HDR image, the adjustments will be retained, but only as non-destructive adjustments that you can still refine when continuing to work with the HDR image in Lightroom’s Develop module. If you are sending the photos from Lightroom to another software tool for creating the HDR image, the adjustments will be applied to the actual pixel values that are created in most cases.

More Detail: As a somewhat “extreme” example, let’s assume you convert the original RAW captures to black and white in Lightroom. If you then assemble the RAW captures into an HDR result, you will have a DNG image that appears as a black and white HDR image.

However, because the adjustments you applied to the original RAW capture are non-destructive, the black and white interpretation for the HDR image is reversible. Simply choose the Color option under Treatment on the right panel, for example, and the HDR image will return to full color.

If, however, you sent the original RAW captures (with a conversion to black and white applied) to software outside of Lightroom for processing, the result will be a black and white image that can’t be reverted to the original color. In other words, the adjustments that had been applied to the original RAW captures will be “baked in” to the final DNG image that is created.

While Lightroom’s HDR processing doesn’t always produce results that are as good as what other software is capable of, this additional workflow flexibility is certainly an advantage when using Lightroom to create HDR images.