High Pass Sharpening


Today’s Question: A friend of mine who is much more experienced in Photoshop than me suggested that I use a High Pass filter to sharpen my images. Can you tell me what that is, how it works, and how I should or shouldn’t incorporate it into my workflow.

Tim’s Quick Answer: The High Pass filter enables an effect that is very similar to what you can achieve with the Clarity slider in Adobe Camera Raw (and Lightroom). It is similar in concept to sharpening, but provides more of a local contrast enhancement that reduces the appearance of haze (and increases perceived detail and sharpness). The technique can certainly be helpful, though I find that the Clarity adjustment often provides a simpler solution.

More Detail: I think one of the best ways to get a sense for the High Pass sharpening technique is to actually try it out on a variety of different images. The process is rather straightforward, and can be automated with an action in Photoshop if you feel you’ll be using this technique on a regular basis.

The first step is to create a copy of the Background image layer, which you can do by dragging the thumbnail for the Background layer on the Layers panel to the “Create a New Layer” button (the blank sheet of paper icon) at the bottom of the Layers panel.

Next, change the blend mode for the new Background Copy layer to Overlay, from the default value of Normal, using the popup at the top-left of the Layers panel. This will create an effect of relatively high contrast in the image, which will be mitigated with the next step.

Now choose Filter > Other > High Pass from the menu to bring up the High Pass filter dialog. The High Pass filter creates an effect similar to an embossed look for the photo, which combines with the Overlay blend mode to enhance local contrast in the image. Start with a value of 10 pixels for the Amount slider, and adjust based on the effect in the image. Note that at this stage the effect will still likely be a bit strong. With practice you’ll get a sense of what value will work best based on the contents and resolution of the photo you’re working with.

Finally, reduce the Opacity setting for the Background Copy layer using the control at the top-right of the Layers panel. This allows you to mitigate the overall strength of the effect for the photo.

There is no question that the use of the High Pass filter in this way can help improve the overall perceived level of detail and sharpness in a photo. Again, the result is very similar to what you could otherwise achieve with a positive value for the Clarity adjustment available in Adobe Camera Raw or Lightroom’s Develop module. That said, for situations where you want to enhance the detail in a photo without the risk of creating the “crunchy” look that can result from excessive sharpening, this High Pass technique can work very well.

Sharpen on Export?


Today’s Question: When exporting a sharpened NEF or TIFF as a JPEG from Lightroom, should sharpening be applied to an already-sharpened master image, or should sharpening be turned off?

Tim’s Quick Answer: Under most circumstances you should apply “capture” sharpening to the original image (the RAW capture, for example) as well as “output” sharpening for the final image.

More Detail: In the context of Lightroom that means applying sharpening to the original capture in the Develop module to compensate for the loss of sharpness caused in the capture process, and sharpening when exporting to optimize the image that has likely been resized.

A variety of factors cause your original capture to be less than perfectly sharp. That includes the analog-to-digital conversion process, various filters on the front of the image sensor, a lens that is not optimally sharp, and other factors. This is the reason for “capture” sharpening, which is the reason for the sharpening controls in the Develop module in Lightroom.

In addition, you want to ensure the final image that will be shared is sharpened for the final output. For images that will be displayed on a monitor or digital projector (such as in a digital slideshow) the need for output sharpening will be relatively modest. For printing that output sharpening will need to be stronger.

In theory you could perform all of your sharpening in one step, but there are some advantages to taking a multi-step approach. In the context of Lightroom a key reason to perform sharpening in two steps is that the initial capture sharpening is being applied to the full-resolution image, while the output sharpening is being applied based on the final image that has been resized for the specific output you’re preparing for.

Moving Photos


Today’s Question: I have been using Lightroom on my MacBook Air, which has very little storage. I would like to move all the photos to an external drive and delete them from the MacBook for more space. How can this be done?

Tim’s Quick Answer: My recommendation is to first make sure you have a full backup of the photos that are currently on your laptop, and then move the photos from the laptop to the external drive. To do so you can create a new “parent” folder on the external hard drive, select all folders on your internal drive that are being managed by Lightroom, and then drag-and-drop those folders to the new external drive.

More Detail: There are, of course, several approaches you could take to move your photos from one drive to another. My preference is to take an approach that ensures there is no risk of Lightroom losing track of your photos. Therefore, I prefer to move the photos from directly in Lightroom.

Again, the first step is to make sure all of your photos are already backed up to a separate hard drive, to ensure you have a way to recover your photos in case something goes wrong during the process of moving photos.

Once you have a backup for your photos, you can connect the external hard drive you want to use as the new location for your photos. This drive will not appear in Lightroom because no photos on the drive are currently being managed by Lightroom. However, you can create a new folder on the drive so that the drive will be shown in Lightroom. To do so click the “plus” icon to the right of the Folders header on the left panel in the Library module in Lightroom, and choose “Add Folder” from the popup menu.

In the dialog that appears, navigate to the hard drive you want to use for photo storage, and click the New Folder button at the bottom-left of the dialog. Type a name for a “master” folder to contain all of your photos, such as “Photos”, press Enter/Return to create the new folder, and click the Choose button to add that folder as an available location in the Folders section on the left panel.

At this point you can select all of the folders in the Folders section of the left panel. To do so, click on the first folder on the list and then hold the Shift key and click the last folder on the list. You can then point to any of the selected folders and drag-and-drop to move all folders to the new destination (the folder you created on the external drive). Note that Lightroom will ask you to confirm you want to actually move the photos on the hard drive.

Once the files have been moved, you will have all of your existing folders (and all of the photos within those folders) reflected in the folder structure on your external hard drive, under the new folder you created on that drive. If you prefer to see only the photos containing your photos and not the “parent” folder you created, you can right-click on the parent folder and choose “Hide This Parent” from the popup menu that appears. At any time you can reveal that parent folder again by right-clicking on any of the folders within that parent and choosing “Show Parent Folder” from the popup menu.

Adobe Bridge Needed?


Today’s Question: As a photographer who currently uses the Lightroom Library module to manage my photo files and use Photoshop and Photoshop Elements as the only other Adobe software. As part of the Adobe CC Photographer package, I see that I am entitled to download and install Adobe Bridge. But since I’m not transferring any files to any other Adobe software, is there any advantage or reason for me to download and install it?

Tim’s Quick Answer: Not really. Some photographers find it easier in certain situations to launch Adobe Bridge (rather than Lightroom) when they want to quickly browse some of their photos. But I find it just as fast (and sometimes faster) to make use of Lightroom, and so I don’t feel any need to have Adobe Bridge installed.

More Detail: One of the advantages of using Lightroom to manage your photos is that you have a central catalog that speeds up the process of filtering images. In addition, if you have Standard (or 1:1) previews generated upon import for all of your photos, you can browse among various photos quickly in Lightroom.

Bridge, by comparison, is a browser without a central catalog (though it does make use of a cache, which provides a degree of benefit in terms of performance in certain situations). As a result, it can take longer in Adobe Bridge to browse among folders and especially to filter images within the folder, because for each folder you navigate to Bridge will need to analyze the images to determine which photos contain which specific metadata values.

There are some potential advantages to using Adobe Bridge if you work among a variety of different Adobe applications, such as InDesign for creating documents and Illustrator for creating illustrations. But if your workflow revolves around photos and you are using Lightroom to organize your photos, in my mind there is no reason to install Adobe Bridge.

If you do choose to make use of Adobe Bridge, I highly recommend that you avoid applying any metadata updates using Adobe Bridge, as that can lead to confusing mismatches of metadata values between Adobe Bridge and Lightroom (or more specifically, between the metadata in your photos and the metadata in your Lightroom catalog).

Changing Capture Time


Today’s Question: I just returned home from 10 days in Costa Rica and realized only now (while reading Ask Tim Grey) that I forgot to reset the date and time on my camera to Costa Rica time. Is there any way to fix this now, after I’ve already uploaded the images to Lightroom?

Tim’s Quick Answer: You can most certainly update the capture time in Lightroom after you’ve imported your photos into your Lightroom catalog. Simply select the photos and then choose Metadata > Edit Capture Time from the menu. Choose the “Shift by set number of hours” option, set the appropriate time difference, and click Change to update the capture time for the photos.

More Detail: It is important to keep in mind that by default when you update the capture time in Lightroom you are only updating the capture time in metadata within the Lightroom catalog. In other words, if you browse your photos using software other than Lightroom (such as Adobe Bridge), you’ll still see the incorrect capture time.

However, you can update the settings in Lightroom so that the capture time for your original capture is updated when you use the Edit Capture Time command. There is a small degree of risk that in the process of updating the capture time for your original captures that the files will be corrupted. However, I’ve never heard of a situation where this process created any problems with the original photos. But again, there is some risk involved.

To change the setting so Lightroom will apply the capture time adjustment to the actual source photos, start by choosing Lightroom > Catalog Settings from the menu on the Macintosh version of Lightroom or Edit > Catalog Settings from the menu on the Windows version of Lightroom. This will bring up the Catalog Settings dialog. Choose the Metadata tab, where you can turn on the “Write date or time changes into proprietary raw files”. Close the Catalog Settings dialog, and from this point forward when you apply changes to the original capture time those changes will be reflected both in your Lightroom catalog and in the original files for your photos.

Drag and Drop Failure


Today’s Question: I know this should be simple, but I can’t get Lightroom to move photos to a different folder using drag and drop. I know it is possible to move photos, since you’ve written about this very task. But when I drag and drop with several photos selected, the photos don’t move and then only one photo is selected. Is this a bug or am I doing something wrong?

Tim’s Quick Answer: To drag and drop photos within Lightroom you need to click (and drag, of course) on the thumbnail for one of the selected photos, not on the frame around the photo.

More Detail: The issue here relates to the difference between clicking on the actual thumbnail of the photo and clicking on the frame around the photo. Clicking on the frame will cause the image contained within the frame to be the only image that is selected, causing all other photos that had been selected to be deselected.

Thus, when you have multiple images selected in Lightroom and you want to drag those photos to a different location (or to a collection) it is important to click on the thumbnail for one of the selected photos rather than the frame around the photo.

Mouse Pointers


Today’s Question: I have three versions of Photoshop (CS2, CS3, and CS6). All of a sudden I have only crosshairs for the mouse pointer for all of my tools. I had this happen years ago but I cannot find what to do to get back to “normal”.

Tim’s Quick Answer: All you need to do is press the Caps Lock key on the keyboard. This keyboard shortcut serves as a toggle between the “brush shape” mouse pointers (generally a circle, for example) and the “precise” option (crosshairs).

More Detail: This is a common source of confusion when you turn on (or off) the Caps Lock option and don’t realize it also impacts the display of the pointer for your mouse. Note that you can also adjust the specific settings for the mouse cursors by going to the Cursors page of the Preferences dialog. You can find the Preferences option on the Edit menu on the Windows version of Photoshop or the Photoshop menu on the Macintosh version of Photoshop.

It is also worth noting that if the brush is too small or too large to display as a circle (for example), then the cursor will also display as a crosshair rather than the brush shape. So, if pressing the Caps Lock key on the keyboard doesn’t solve the issue of seeing a crosshair when you expect to see a brush shape, make sure the brush size is not too large or too small.

Photo Info


Today’s Question: I was watching a presentation about Lightroom and when the presenter moved from one image to the next, exposure information appeared briefly over the photo. I would like to enable this option but for the life of me can’t find it. Can you tell me how to enable this option?

Tim’s Quick Answer: The “trick” here is to turn on the “Show briefly when photo changes” checkbox for one of the Loupe Info options in the Library View Options dialog, which you can find by choosing View > View Options from the menu bar.

More Detail: The information display you’re referring to is the Info Overlay for the loupe view, which you can display (or hide) by pressing Ctrl+I on Windows or Command+I on Macintosh. If you want the info to appear briefly each time you switch to a different image, you can configure that option in the Library View Options dialog. To do so, select View > View Options from the menu and click the Loupe View tab. Make sure the “Show Info Overlay” checkbox is turned off, and then turn on the “Show briefly when photo changes” checkbox for Loupe Info 1 or Loupe Info 2.

More Detail: By turning on the “Show briefly when photo changes” checkbox for Loupe Info 1 or Loupe Info 2, the information for the applicable info option will appear briefly each time you switch to a different image, rather than having to toggle the display of the information manually.

Note that you can also adjust the specific information included with the two Loupe Info options. Each of the Loupe Info options includes three popups, where you can select specific information to be displayed based on the metadata for the current image.

Precise Color Values


Today’s Question: I have a client that hires me to do some product photography, where the colors of their products need to be very accurate based on specific RGB values. I know I can see the color values for a given area by opening the Info panel in Photoshop and moving my mouse over the area. But as soon as I move my mouse back to make changes to my adjustment, the Info panel numbers disappear. Is there a way to keep the numbers visible while I’m working on adjusting the color?

Tim’s Quick Answer: The solution to this issue is to place one or more color samplers on the image so that you can view the values for those samplers on the Info panel. Start by clicking and holding the mouse button down on the button for the Eyedropper tool on the toolbox to bring up a flyout menu, where you can choose the Color Sampler tool. Then click on the image in the areas you want to evaluate, adding up to ten color samplers (up to four with older versions of Photoshop. You can then view the value for each of those color samplers on the Info panel.

More Detail: When you are using color samplers on your image to adjust pixel values within the image, the values shown for each color sampler on the Info panel will have two values for each of the color channel when you are applying an adjustment. The value to the left is the “before” value, before your adjustments were applied. The value to the right is the “after” value. So you’ll want to pay attention to the values on the right for each color sampler shown on the Info panel as you apply your adjustments aimed at achieving specific color values.

Note that when you’re finished working with the color samplers you can remove them from the image. To do so, first make sure the Color Sampler tool is active. Then hold the Alt key on Windows or the Option key on Macintosh, and click on the color sampler in the image to remove the color sampler. Note that the mouse pointer will show a pair of scissors when you are holding the Alt/Option key and hover the mouse over a color sampler.

Partial Pixel Values


Today’s Question: In a recent eNewsletter you stated that in camera “With most cameras each individual ‘pixel’ on the image sensor is only recording a single color value (generally red, green, or blue)”. Can you expand on this and explain how we end up with all three color values for each pixel from such slim camera data?

Tim’s Quick Answer: There are certainly exceptions, but with most digital cameras the image sensor uses a sensor where each “pixel” is only recording a single color of light. Essentially each photosite on the sensor has a colored filter in front of it, so each photosite records only red, green, or blue light. Either in the camera (in the case of JPEG capture) or in post-processing (with RAW capture) the “other” values are calculated based on surrounding pixel values.

More Detail: It might seem a little outrageous that two-thirds of the information in a digital photograph is created after the capture, but it is true for the vast majority of digital camera sensors. And I can make the situation sound even worse.

The red, green, and blue photosites on the image sensor aren’t distributed in equal quantities in most cases. On a typical sensor half of the photosites are capturing green light, one-quarter are capturing red light, and one-quarter are capturing blue light. This is because the green light represents the most prominent light in the scene based on nature of human vision. One way to think of this is to consider that in an RGB image, the green channel will most often represent the best black and white image if you could only choose among the three channels to create a black and white image.

So, how is that “extra” information created out of thin air? To be sure, the process is complicated and there are many advanced algorithms at work behind the scenes when processing a RAW capture. But in basic concept it isn’t actually too complicated.

Instead of thinking about the final color photograph, think about the individual channels that comprise that color image. Each of the channels (red, green, and blue) are black and white images that reflect how much red, green, or blue light should be combined to create the color value for each pixel. You can get a sense of this by viewing the individual color channels for a color image using the Channels panel in Photoshop.

Imagine a black and white photo, consisting of many shades of gray. Now imagine that every other pixel is blank. That is what the unprocessed green channel looks like for a RAW capture, in terms of the image sensor only recording green light for half of the pixels on the image sensor. The software simply (I use the term loosely) needs to calculate the missing values in between each green pixel value. In theory you could just fill in the blanks with the average of the two adjoining pixel values, but of course in the real world the math is far more complicated.

Keep in mind also that besides having half of the pixel values for the green channel, the software processing a RAW capture also has red and blue values for the surrounding pixels. So there is a reasonable amount of information to provide an ability to infer pixel values.

Of course, for the red and blue channels the situation is a little more challenging, since fully three-quarters of the information is “missing” for those channels. But the same basic process applies (with complicated math in the background) and the “other” color values for each pixel can be calculated.

To be sure, in the early days of digital capture the task of “filling in the blanks” (a process that is generally referred to as demosaicing, by the way) wasn’t performed very well. Over the years the software for RAW processing has gotten much more advanced. This enables the initial color information to be calculated more accurately than was the case with earlier software, and it also means that greater detail and sharpness can be preserved.

I suppose it would be fair to say that in simple concept, the task of demosaicing is relatively straightforward. You “simply” need to fill in the blanks based on what you can infer from surrounding pixel values. But, of course, the math behind this processing is quite complicated. Thank goodness there are very smart software engineers who have tackled this task and provided us with a variety of high-quality RAW-processing software!