Bit Depth in Lightroom

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Today’s Question: Does Lightroom process RAW captures in a 16-bit per channel mode?

Tim’s Quick Answer: Yes, RAW captures within Lightroom are processed within a 16-bit per channel workspace internally. Furthermore, the original RAW capture file is not directly modified when working within the Develop module in Lightroom.

More Detail: Lightroom provides a non-destructive workflow in the context of the Develop module, meaning your adjustments don’t affect the original image file on your hard drive. Therefore, in some respects you could say that the internal bit depth is not a significant factor, since it only really affects the preview you’re seeing in the Develop module while applying adjustments.

The effect of the higher bit depth really takes effect in the context of the final image you might share, whether that involves printing, presenting online, or simply creating a derivative image. It is at that point that the information within the original RAW capture (or other file type) is processed with the adjustment settings you’ve applied.

By using a 16-bit per channel mode internally, Lightroom helps ensure you will maintain the smoothest gradations of tone and color possible within your images. The resulting data is then used when you share your photo. If necessary, the original 16-bit per channel data may be converted to 8-bit per channel data if you have saved, for example a JPEG image. But by working in a 16-bit per channel space internally, that final image will be of the highest quality possible.

Bit Depth for Filters

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Today’s Question: As an add-on question related to working in 16-bit per channel mode, can you offer a recommendation for how to fit in filter effects in Photoshop that generally only work on 8-bit files? Can the 16-bit file be “legitimately” converted to 8-bit for filter gallery effects and then converted back to 16-bit afterwards?

Tim’s Quick Answer: It is not recommended that you convert an image from 16-bit per channel mode to 8-bit mode and then back to 16-bit mode, as doing so may cause you to lose most of the benefits of working at a high bit depth in the first place. Instead I recommend making a copy of the image for the purposes of applying creative filters.

More Detail: There are two basic approaches you could take to applying creative filters that only support 8-bit per channel mode when your master image is in the 16-bit per channel mode.

The first approach is to simply create a copy of the master image. With that image open, first be sure to update the file on your hard drive by choosing File > Save from the menu. Then create a copy of the image by choosing Image > Duplicate from the menu. In the Duplicate Image dialog that appears, turn on the Duplicate Merged Layers Only checkbox. This will cause the duplicate image to be a flattened version of the original, so that all adjustments are applied directly to the pixel values. Click the OK button in the Duplicate Image dialog to create the duplicate.

At this point I recommend closing your original master image that has all of the layers intact, just to avoid any confusion with the derivative image you’re currently working on.

Next, convert the duplicate image to the 8-bit per channel mode by choosing Image > Mode > 8 Bits/Channel from the menu. Then choose File > Save As from the menu, and save the derivative image. In general I recommend saving this duplicate image in the same folder as the master image, with the same base filename, but with text added to the end of the filename to indicate it is a creative interpretation of the original.

You can now apply any of the creative filters you’d like, such as by choosing Filter > Filter Gallery from the menu. You may want to create one or more copies of the Background image layer as part of this process, depending on your specific intent for the image. For example, an additional layer would be necessary if you wanted to use a layer mask to apply a creative effect only in specific areas of your image.

When you are finished applying creative effects to the derivative image, be sure to choose File > Save to save the final changes to that image. When you’re finished, your original master image with all layers intact will of course still be available.

Lightroom versus Bridge

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Today’s Question: I’ve just read your clarification of using Lightroom versus Camera Raw. Not being a user of Lightroom, I’m wondering if you could give a similar clarification between Lightroom and Adobe Bridge. I’ve recently started using Camera Raw for some processing, and use Bridge to label, rank, and search my photos. But I’m wondering if you can clarify what advantages you find that Lightroom has over Bridge for managing your portfolio.

Tim’s Quick Answer: The core difference between Adobe Lightroom and Adobe Bridge is that Lightroom uses a catalog that serves as a central database for managing your photos. The primary advantage of the catalog is that it enables you to more quickly search across your entire collection of photos, and to review photos even when the source files are not available. The disadvantage is that the catalog adds an additional element to manage in your workflow.

More Detail: In terms of your overall workflow for managing your photos, Lightroom and Bridge provide the same basic tools. For example, both enable you to identify favorite photos with star ratings, add keywords, and browse among photos across a large number of folders. Fundamentally, you can manage the same basic workflow with either application.

The difference is the catalog, which can be an advantage or disadvantage based on your perspective. I consider the catalog to be the biggest reason to consider Lightroom as the foundation of your workflow. That said, the catalog is also the perhaps the most maligned feature of Lightroom.

Because of the catalog, Lightroom makes certain tasks possible that would be difficult or impossible with Lightroom. With Lightroom you can very easily browse and filter based on your entire library of photographic images. For example, with just a few clicks you can have Lightroom display every single image that you have assigned a five-star rating to.

In addition, because the Lightroom catalog contains both preview images and all of the metadata for your photos, you can actually browse and perform certain tasks with your photos even if the actual image files aren’t available. So, for example, if your photos are stored on an external hard drive but that drive is not connected to your computer, you can still browse those photos and review or update the metadata for the images.

That said, Lightroom also requires that you manage the catalog to a certain extent. As readers of my Ask Tim Grey eNewsletter can probably appreciate, many photographers have struggled with making proper use of the Lightroom catalog. For example, they have updated folders and images outside of Lightroom, creating a variety of challenges within the context of a Lightroom based workflow.

On balance, I very much prefer the benefits provided by the Lightroom catalog. That said, I do recognize that there are inherent challenges involved in managing that catalog. As a result, I do think it is important for each photographer to consider the potential advantages and disadvantages of each potential approach to their image-management workflow.

Single-Image HDR

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Today’s Question: I’ve got a single image that has a pretty broad range of tonal values. Is there a way to create an HDR image from a single photo? I tried creating additional versions of the original (-2, -1, +1, +2 stops) and then combining them, but that didn’t work. Do you have any suggestions of what would work?

Tim’s Quick Answer: Put simply, you can’t create a true high dynamic range (HDR) image from a single exposure. You can, however, use the tone-mapping feature of most HDR processing software to apply adjustments to that single image.

More Detail: An HDR image involves combining multiple exposures into a single file, blending all of the information from the multiple images into a single processed image with a higher range of tonal values. This is the reason that an initial HDR image assembled from multiple 16-bit per channel captures will generally be a 32-bit per channel HDR image.

That 32-bit per channel image then needs to be tone-mapped to a “normal” tonal range represented by a 16-bit per channel image. This tone-mapping step can be applied to any image, even if it is not a true HDR image.

Some software tools for processing HDR images allow you to use multiple images processed from a single capture, using different exposure adjustments for each copy of the image. This would require that the RAW captures be processed and saved in another image format such as TIFF, however. If you simply made multiple copies of the same RAW capture with different adjustments saved in metadata, the HDR software would not be “fooled”, since the underlying RAW captures would all contain the same capture data.

So, there is no real reason to process the same RAW capture with multiple exposure adjustment variations. Instead you can simply open the original RAW capture in the HDR software, using the tone-mapping features to create the interpretation you prefer. Put simply, applying adjustments to create multiple interpretations of a single capture does provide any additional data compared to the single original RAW capture. To truly leverage the benefits of HDR imaging, you need to capture multiple bracketed exposures in the camera to begin with.

Bit Depth for Adjustments

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Today’s Question: Would it be better to apply routine adjustments to an image while the file is still 16-bit per channel mode?

Tim’s Quick Answer: Yes! I always recommend working in the 16-bit per channel mode for your “master” image, only using the 8-bit per channel mode to save derivative copies of the photo.

More Detail: When you share a photo online or produce a print of a photo, you really only need 8-bit per channel color. That translates into more than 16.7 million possible color and tonal values, which happens to be about the same number of values the human visual system is estimated to be capable of seeing.

However, there are advantages to having some additional “headroom” for your adjustments. When you apply an adjustment to a photo, you will often lose a degree of detail in the process. For example, a strong increase in contrast might cause a reduction in the level of detail in the brightest highlights and the darkest shadows.

When working with an image in the 16-bit per channel mode, you have more than 281 trillion possible color and tonal values available. Thus, even with very strong adjustments you will likely still have more than enough information to support the 8-bit per channel mode that represents a baseline in terms of how much information you need to share an image with optimal quality.

Therefore, I highly recommend always working with your “master” image in the 16-bit per channel mode. The 8-bit per channel mode should only be used for saving copies of an image for sharing with others.

It should be noted, by the way, that converting an 8-bit per channel image to the 16-bit per channel mode does not provide the benefits available for true 16-bit per channel images. In other words, you’ll need to start with a RAW capture in order to retain the full bit depth of the original capture. Then, working in 16-bit per channel mode will ensure maximum flexibility for your master image, so you’ll be able to share that image with the best quality possible.

Threshold versus Masking

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Today’s Question: Does the Threshold control in Photoshop’s Unsharp Mask filter do the same thing as the Masking control when sharpening in Lightroom?

Tim’s Quick Answer: The Threshold control for Unsharp Mask in Photoshop and the Masking control for sharpening in Lightroom are very similar in terms of the overall concept involved and the results you can expect.

More Detail: As noted in an Ask Tim Grey eNewsletter last week, the Threshold feature of the Unsharp Mask filter in Photoshop enables you to mitigate the effect of sharpening in areas of relatively smooth texture. In short, the Threshold control enables you to set a minimum level of contrast that is required before the Unsharp Mask filter enhances contrast to create a sharpening effect.

The Masking control that is available with the sharpening in both Adobe Camera Raw and Lightroom’s Develop module provides a very similar feature. By increasing the value for Masking you are requiring that a certain degree of contrast exist before any additional contrast is added via sharpening. In other words, the Masking control defines a threshold similar to the Threshold control for the Unsharp Mask filter.

The context of the question addressed last week was a comparison of the Unsharp Mask filter compared to the Smart Sharpen filter in Photoshop. If you are applying sharpening in Adobe Camera Raw or Lightroom’s Develop module, you can achieve the same basic effect of the Threshold control available for Unsharp Mask by increasing the value for Masking.

Note, by the way, that when increasing the value for Masking in Adobe Camera Raw or Lightroom, you can hold the Alt key on Windows or the Option key on Macintosh to see a black-and-white preview of which areas will still be sharpened versus which areas will not be sharpened. With the Alt/Option key held down, when you drag the slider for the Masking slider the preview image will appear white where sharpening is going to be applied and black in areas where sharpening will be blocked.

Sharpening versus Midtone Contrast

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Today’s Question: I was always taught that the High Pass filter was a superior method of sharpening in Photoshop.  And although I was aware of it, I didn’t use it much.  I only learned recently that with a very small radius and use of the Hard Light mode, I can produce significant, but not overly obvious, sharpening of images with a bit of blur.  What are your thoughts about High Pass? And is there a way to achieve any of these kinds of effective sharpening in Lightroom?

Tim’s Quick Answer: The “High Pass” technique is similar in overall effect to sharpening, depending on the settings used. In general practice it tends to provide more of a midtone contrast enhancement for accentuating detail, rather than a true sharpening effect. Lightroom provides similar options with Clarity and Dehaze.

More Detail: Sharpening involves (in a very general way) enhancing contrast where contrast already exists. In the context of a typical motivation for sharpening, that involves enhancing the contrast for fine details in an image in order to improve the perceived sharpness of the image.

Of course, it is also possible to “expand” that sharpening effect across a larger area so that instead of sharpening fine detail you are enhancing overall midtone contrast, reducing the appearance of haze, and adding impact to the photo in the process. This is really just a variation on a theme when it comes to sharpening.

Because there are different motivations for applying a sharpening effect (among other reasons), there are seemingly countless approaches you can take to improve perceived sharpness, increase the appearance of detail, and reduce the appearance of haze in an image. The “High Pass” technique is one of those.

The High Pass approach to sharpening (or detail enhancement) involves duplicating the Background image layer, changing the blend mode for the duplicate layer to one of the “contrast” options (such as Overlay or Hard Light), and then applying the High Pass filter to that duplicate layer (with a Radius value of somewhere around 10 pixels, though the optimal setting can vary significantly).

This approach can be very beneficial for enhancing overall detail with minimal risk of problematic halos in the image. As such, it is a technique I highly recommend. I would simply add that it isn’t really an alternative to sharpening in most cases, but rather something of a creative effect.

As for Lightroom (or Adobe Camera Raw), you can achieve a very similar effect to the High Pass sharpening technique by using a positive value for the Clarity adjustment, or for the Dehaze adjustment. The Dehaze adjustment is primarily focused on reducing the appearance of haze in a photo, while the Clarity adjustment is more focused on overall midtone contrast and enhancement of texture and detail.

Initial RAW Processing

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Today’s Question: Why is Lightroom better than Camera Raw for pre-Photoshop processing?

Tim’s Quick Answer: Lightroom is not “better” than Camera Raw when it comes to processing the initial RAW captures before performing additional work in Photoshop. In fact, both will produce the exact same results.

More Detail: This question was in response to a question from an Ask Tim Grey eNewsletter last week, in which I discussed the percentage of images I send to Photoshop from Lightroom. What I was really addressing there was how important Photoshop is for processing my images. Recently, with improvements in Lightroom, I’ve found that I’m using Photoshop less and less.

The context of my answer related to the fact that I use Lightroom to manage my library of photographic images, and therefore I use the Develop module in Lightroom as the initial basis of optimizing the appearance of my photos.

That said, if you are not a Lightroom user, then you could substitute Adobe Camera Raw for Lightroom in terms of initial processing of your RAW captures. Both Lightroom and Camera Raw share the same processing engine, so you will find the same adjustment controls with both, and you can expect the same results with both assuming the same settings for all adjustments.

So, when it comes to overall image quality and the specific results you can expect, you can think of Camera Raw (in Photoshop) and the Develop module in Lightroom as being equal. The only real question is what workflow makes the most sense from an organizational standpoint, which in turn will impact your workflow for optimizing your photos.

Bridge to Lightroom

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Today’s Question: I’m interested in using Lightroom, but after years of using Bridge as an entry into Photoshop, I like and much prefer to maintain the file system I’ve set up in Bridge for my images. How do I do keep the Bridge file system while using Lightroom?

Tim’s Quick Answer: You can absolutely maintain the organizational structure and workflow you’ve defined in Adobe Bridge after you transition to Lightroom. You just need to make sure that you stop actually using Bridge once you switch to Lightroom.

More Detail: Many photographers seem to misunderstand the role Lightroom plays in your workflow, in large part because Lightroom employs a catalog rather than serving as a simple image browser.

The first thing that I think photographers should understand about Lightroom is that the Lightroom catalog is simply a reflection of your existing folder-based organizational structure. Lightroom also enables you to view (and update) the metadata you may have added through other applications such as Bridge.

The process of transitioning from Adobe Bridge to Adobe Lightroom is incredibly simple. Let’s assume you have stored all of your photos on a single external hard drive with a folder structure that suits your needs, and that you’ve been using Adobe Bridge to browse those images and update the metadata as appropriate.

To get started with Lightroom you could simply import all of your photos. With a new catalog in Lightroom you can choose the Import feature. Then set the source of the import to the external hard drive, and make sure the option to include all subfolders is enabled. With the “Add” option set at the top-center of the Import dialog, you can then click the Import button to initiate the process.

Once this import is complete your entire library of photos can be viewed within your Lightroom catalog. The entire folder structure for those photos will be visible in the Folders section of the left panel in the Library module, and all of the metadata for those photos can be found on the right panel in the Library module.

The important thing at this point, however, is to stop using Adobe Bridge altogether, and instead use Lightroom as the starting point for every task you need to perform with your images.

If you want to make sure you completely understand Lightroom, including help on configuring Lightroom to best suit your needs, you might be interested in my bundle of video courses on Adobe Lightroom, which you can find here:

http://timgrey.me/atgmess

Photoshop Frequency

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Today’s Question: Perhaps this is just a curiosity, but I wonder what percentage of your images you send to Photoshop versus processing completely in Lightroom.

Tim’s Quick Answer: At this point in terms of image optimization the majority of my photos are processed exclusively within Lightroom, with fewer than ten percent being sent to Photoshop for optimization. Put simply, with each new update to Lightroom I’m finding less need to employ the power of Photoshop.

More Detail: As many of my longtime readers know, I’ve been a big fan of Photoshop for a very long time. Many may have noticed that it also took me a little while to fully embrace Lightroom as the cornerstone of my workflow. As the Develop module in Lightroom has improved over the years, I’ve also gradually shifted my workflow to focus more on Lightroom and much less on Photoshop.

To be sure, I still employ Photoshop for difficult challenges. Of course, as I’ve improved my photographic workflow over the years, I have fewer and fewer “difficult” images. But there are situations where I need the additional power of Photoshop to make the most of a photo.

For the most part the reasons I employ Photoshop are to perform sophisticated image cleanup and to apply precise targeted adjustments. While Lightroom includes tools for both of these tasks, they are not as powerful or flexible as what is available in Photoshop.

As much as I love the power of Photoshop, and as much as I love exercising incredible control over my photos, I also appreciate having a workflow that is as streamlined as possible. Therefore, since I use Lightroom as the foundation of my workflow, I try to leverage Lightroom for as much of my work as possible. I only employ other tools when there is a clear advantage beyond what Lightroom is capable of.