Ask Tim Grey

Today’s Question: I was told (without explanation, mind you) that I should never store my Lightroom Classic catalog in the Pictures folder in the operating system. My understanding is that the Pictures folder is the default location for catalogs, so is there really any reason I should avoid storing the catalog there?

Tim’s Quick Answer: The only reason I would avoid storing the Lightroom Classic catalog in the Pictures folder is if that folder is being synchronized to the cloud with a service such as iCloud or OneDrive. Otherwise, it is perfectly fine to store the catalog in the Pictures folder or any other convenient location (ideally on a fast storage device such as SSD).

More Detail: In general, you can store your Lightroom Classic catalog in any folder on any hard drive, except for a network storage location. Network storage is not an option for the Lightroom Classic catalog due to the architecture of the software.

However, as a general rule I don’t recommend storing a Lightroom Classic catalog in cloud storage. Storing the catalog in the cloud creates a considerable risk of metadata mismatches and even corruption of the catalog.

To be fair, the issue here isn’t technically the use of cloud storage for the catalog, but rather the risk of accessing the catalog from more than one computer via cloud storage. If you only access the catalog from a single computer and never use any other computer or device to access the catalog, cloud-based storage is generally safe. But if you were to open the catalog from a second computer, even if you only use one computer at a time to access the catalog, there are considerable risks.

If you’re only using Lightroom Classic on a single computer, having the catalog in a folder (such as Pictures) that is being synchronized to the cloud is generally safe. In effect, the catalog files are just being backed up to the cloud, while being updated on the single computer. However, if another computer or device is used to access the catalog files, there is a serious risk of data corruption.

In my own testing with a catalog stored in the cloud, I was able to create metadata mismatches in the catalog instantly by making changes on two computers. I was able to corrupt the catalog to the point it couldn’t be used within about five minutes. To me it isn’t worth the potential risk even if you’re only using one computer, so as a rule I recommend that the catalog not be stored in a folder that is synchronized to the cloud via services like iCloud and OneDrive. Instead, I would store the catalog in a location on the internal hard drive that is not being synchronized to the cloud, or on an external hard drive.

Today’s Question: Can you clarify what is meant by “tone mapping” for HDR images? Why is it an option when using HDR Pro in Photoshop but not with Camera Raw [or Lightroom Classic]?

Tim’s Quick Answer: The term “tone mapping” refers to taking a high dynamic range (HDR) image and converting the pixel date to the tonal and color range of a “normal” 16-bit per channel image.

More Detail: A high dynamic range (HDR) image contains a much wider range of tonal values than a “normal” photograph. The way this is accomplished is by taking the image data from multiple bracketed exposures and blending them into a 32-bit per channel image.

For context, an 8-bit per channel (such as a JPEG capture) can contain up to almost 16.8 million possible color values. A 16-bit per channel image (the maximum for a raw capture, though not all cameras support this high a bit depth) can contain more than 281 trillion possible color values. An image in the 32-bit per channel bit depth can contain color values numbering more than 79 with 27 zeroes, which happens to be more than 79 octillion possible color values.

Of course, the incomprehensibly large number of possible color values for a 32-bit per channel image don’t mean very much in the context of a normal photographic workflow. That’s especially true considering that normal human vision is estimated to be close to matching 8-bit per channel color.

But 32-bit per channel images aren’t intended to provide extreme possibilities in terms of color and tonal values available. Rather, they’re meant to contain huge amounts of image data for special purposes. To put such an image to meaningful use in a photographic workflow it needs to be converted to 16-bit per channel mode, and in the context of converting an HDR image to a “normal” image the term for that process is tone mapping.

So, you can think of tone mapping as the process of taking the incredibly huge range of color and tonal values in a 32-bit per channel HDR image so they fit into a “normal” 16-bit per channel image. This is a process that can be handled directly by software that enables you to create an HDR image in the first place, making it somewhat “invisible” to the user. For example, if you assemble an HDR image in Camera Raw as explained in a previous Ask Tim Grey answer, you are using Camera Raw to perform the tone mapping step to translate the 32-bit per channel HDR data to a 16-bit per channel image.

Today’s Question: I was recently told I should NOT enable profile-based Lens Corrections but SHOULD enable Chromatic Aberration Removal upon import to Lightroom Classic. I am now confused. I am sure I was told just the opposite once. What is the best practice? And how do I re-do my own preset upon import with these items checked or not as needed? Right now I have Lens Corrections on and Chromatic Aberration off.

Tim’s Quick Answer: I prefer to apply profile-based lens corrections as well as chromatic aberration reduction to all images by default when importing into Lightroom Classic. If there are any images where you’re not happy with the results you can always turn one or both of those options off.

More Detail: In general, I find that most images benefit from profile-based lens corrections. I also find that enabling chromatic aberration removal either improves the image or doesn’t have any impact, with no negative consequences of leaving it turned on for all images.

That said, ultimately these options will either be turned on or turned off based on your preferences in general and the needs of an individual photo. Therefore, I recommend deciding whether to apply these adjustments to all images by default based on how likely you are to want to make use of these adjustments.

I tend to prefer enabling both of these adjustments, because I find that in the vast majority of cases they provide an improvement for my photos. If I find an image where the effect is problematic, or that images captured using a particular lens generally benefit from not having the adjustments applied, I can always turn them off.

Conversely, if you find that you generally prefer not to have the adjustments enabled, you could leave them off (which is the default for both) and only apply them when they provide a benefit.

If you have an existing Develop module preset you’ve been applying during import, and you change your mind about which adjustments you want to include, it is easy to make a change. To get started, I recommend selecting an image that you haven’t yet applied adjustments to or resetting the adjustments for an image that can be used for this purpose. Then apply the preset from the Presets section of the left panel in the Develop module to the image. If the “Enable Profile Corrections” and “Remove Chromatic Aberration” checkboxes are not set the way you prefer them, you can turn those checkboxes on or off based on your preference.

Then right-click on the preset on the left panel and choose “Update with Current Settings” from the popup menu. This will update the applicable preset to reflect the changes in settings you made. Just keep in mind that changing the preset will not alter the adjustment settings to images to which the preset had previously been applied, so you may need to make changes to some of your existing photos based on your preferences.

Today’s Question: If I understand correctly, I could assemble an HDR [high dynamic range] image in Photoshop or in Camera Raw. Do you recommend one over the other, or are they the same?

Tim’s Quick Answer: Yes, you can assemble HDR images using either Camera Raw or a feature within Photoshop. I highly recommend Camera Raw because based on my experience, it consistently produces better quality results.

More Detail: Photoshop has long offered the HDR Pro feature for combining multiple exposures into an HDR image. However, I consistently find that Camera Raw provides superior results with a more streamlined workflow, and so highly recommend Camera Raw over HDR Pro for assembling HDR images.

If you want to test HDR Pro for yourself, you can select the multiple bracketed exposures you want to merge into an HDR image within Adobe Bridge. Then go to the menu and choose Tools > Photoshop > Merge to HDR Pro. The selected images will be opened into a layered image in Photoshop, and the HDR Pro dialog will appear. You can apply the tone-mapping directly with HDR Pro by selecting “16 Bit” from the Mode popup. However, in general I recommend choosing “32 Bit” and then keeping the “Complete Toning in Adobe Camera Raw” checkbox turned on. This enables you to complete the tone-mapping for the HDR image using Camera Raw. Of course, you can also simply perform all processing in Camera Raw, which I think makes more sense and, in my experience, produces better results.

To create an HDR image in Camera Raw you can first select all the exposures for the HDR image in Adobe Bridge. Then double-click on any of the selected raw captures to open them in Camera Raw. On the filmstrip in Camera Raw select all the images, then either right-click on one of the images or click the “more” button (the ellipsis icon) at the top-right of one of the thumbnails. From the popup menu choose “Merge to HDR”.

This will bring up the HDR Merge Preview dialog, where you can configure the settings for creating the initial HDR image. Click the Merge button, and the HDR image will be created and opened in Camera Raw. You can then use all the available adjustments to fine-tune the result. You can then click the Open button at the bottom of the Camera Raw dialog to open the HDR image in Photoshop, save the image, and apply any additional adjustments you’d like.

Today’s Question: I remember a long time ago seeing you demonstrate a technique where you could combine two images based on brightness values, so that you could reveal only the brightest areas of one image in another. In your example you were combining bright clouds into another image. Can you remind me how that is done?

Tim’s Quick Answer: The technique you’re referring to involves the use of the “Blend If” sliders in Photoshop to blend two layers based on brightness values for each layer.

More Detail: While the “Blend If” sliders technique only works well under relatively specific conditions for combining two images into a composite, when it does work it can seem quite magical. The key is to use the “Blend If” sliders when there is a very clear separate in tonal values among the areas of an image you want to hide versus reveal in the composite image. Note that at the end of this answer I’ll reference a video tutorial that is available on this subject.

For example, let’s assume you want to create a composite image where a subject photographed against a bright sky is combined with a better sky in another image. You would first open these images as layers in Photoshop. From Adobe Bridge you can select the two images and then from the menu choose Tools > Photoshop > Load Files into Photoshop Layers. From Lightroom Classic you can select the images and from the menu choose Photo > Edit In > Open as Layers in Photoshop.

As you’d like, you can rearrange the order of the layers by dragging the thumbnails into a different order on the Layers panel. In this case we’ll assume the image of a subject against a bright sky is the upper layer and the replacement sky is the lower layer.

At this point you can select the upper image layer and then click the “Add new Layer Style” button (the “fx” icon) at the bottom of the layers panel and choose “Blending Options” from the popup menu.

In the Blending Options tab of the Layer Style dialog go to the Blend If section and make sure the popup next to the “Blend If” label is set to Gray so you’re blending images based on brightness values. Since at this point we want to hide portions of the current layer, we’ll drag the black slider if we want to hide dark areas and the white slider if we want to hide bright areas. In this example we want to hide the bright sky in this layer to reveal the better sky below, so we would drag the white slider toward the left.

After finding the optimal position for the slider in terms of hiding and revealing pixels to create a good composite image, some feathering or blending will be needed to improve the quality of the result. To enable this feature, hold the Alt key on Windows or the Option key on Macintosh while dragging one side of the white slider outward. This will split the slider into two smaller handles, and the gap between those handles represents feathering for the composite image. Adjust the position of both halves of the slider to optimize the composite and blending of the images.

If you want to reveal additional areas from the image below you can use the “Underlying Layer” sliders. For example, if there are bright clouds in the image of the sky for the lower layer, you might want to have some of those clouds appear over the relatively dark subject, to make it appear the subject is partially hidden among the clouds. To reveal pixels from the underlying image you drag the black slider to reveal dark areas or the white slider to reveal bright areas. So, in this example you would drag the white slider for Underlying Layer to reveal some of the bright clouds below, splitting the slider into two halves as outlined above so you get a blended result.

If you’re a GreyLearning Ultimate Bundle subscriber, you can watch the recording of my presentation on “Creating Composite Images” in my Photoshop Ultimate Live Learning series. After signing in to the GreyLearning website (https://www.greylearning.com/users/sign_in) you can follow this link to view the recording (the Blend If topic starts at about 34:22 in the recording):

https://www.greylearning.com/courses/take/photoshop-ultimate-live-learning/lessons/74839010-creating-composite-images-ps-27-6-0

If you’re not already a GreyLearning Ultimate Bundle subscriber, you can sign up for just $99 per year by using the link below to get started. You’ll then have full access to all content in the GreyLearning library, including all recordings from the Ultimate Live Learning series. Here’s the link:

https://www.greylearning.com/bundles/greylearning-bundle?coupon=golive

Today’s Question: Is there a way to combine two (or more) photos into a composite image in Lightroom Classic?

Tim’s Quick Answer: To combine two or more images into a composite image you would need to send the images to Photoshop from Lightroom Classic. The only options for merging multiple images together directly in Lightroom Classic are to create a high dynamic range (HDR) image, a composite panorama, or an HDR panorama.

More Detail: Lightroom Classic can blend multiple exposures into an HDR or multiple frames into a composite image. It can even perform both tasks in one process to create an HDR panorama. However, it isn’t able to combine images into a composite, such as if you were replacing the sky in one image using the sky from another image. That type of composite image would require Photoshop.

To get started in Lightroom Classic you can select the two (or more) images you want to combine into a composite image. Then go to the menu and choose Photo > Edit In > Open as Layers in Photoshop. This will open the selected images into a single layered document in Photoshop.

At that point you can use layer masks to combine various image elements, blend modes to combine the images such as for a multiple exposure effect, or otherwise work with the layers to create a composite image. When you’re finished simply choose File > Save to save the resulting image with layers intact (based on the External Editing settings in Preferences in Lightroom Classic) and close the image.

When you go back to Lightroom Classic the composite image can be found in the same folder as the source images used to create the composite.

Today’s Question: I’m relatively new at using Lightroom Classic, and so I’m sometimes nervous to perform certain tasks in my catalog. Is there a way to use a “test” catalog separate from my “real” catalog for purposes of practicing various techniques to build confidence before do the work in my real catalog?

Tim’s Quick Answer: Yes, you could create a separate catalog for test purposes, using copies of some of your photos to populate that catalog to use for practice. Just be sure that your real catalog is set as the default in Preferences to help make sure you’re always using your real catalog for your real workflow.

More Detail: If you’re just getting started with Lightroom Classic (or you lack confidence using some of the features) it can be a good idea to create a test environment to enable yourself to practice without any concern that you’ll cause problems with your primary catalog.

The first step would be to create a new catalog, which you can do by selecting File > New Catalog from the menu in Lightroom Classic. Navigate to the location where you want to save the catalog, enter a meaningful name in the Save As field, and click the Create button. This will create a folder and catalog files in the designated location. You can then open that catalog, which initially will be empty without any images.

I then recommend copying some of your photos to a test folder, separate of your primary photo storage, for testing purposes. For example, you could copy (not move!) a handful of folders containing photos to a “Lightroom Classic Test” folder. Then in your test catalog you can click the Import button at the bottom of the left panel, select your top-level folder containing test images, and turn on the “Include Subfolders” checkbox, all on the left panel of the Import dialog. At the top center choose the “Add” option, adjust settings as desired on the right panel, and click the Import button at the bottom right.

Within this test environment you can practice any techniques and make use of any features you’d like, without having to be concerned about impacting your real catalog and photos.

I also strongly recommend setting your primary catalog as the default catalog in Preferences if you haven’t done so already. This can be set using the Default Catalog popup on the General tab of the Preferences dialog in Lightroom Classic. Doing so will cause Lightroom Classic to open that catalog automatically whenever you launch the software, rather than just opening the catalog that was opened most recently. This can help avoid confusion, as you’ll always know that your primary catalog is opening every time you launch Lightroom Classic. If you want to open your test catalog, you can simply choose File > Open Recent and choose the test catalog from the menu.

Today’s Question: I was reading a tutorial about editing raw images from Lightroom Classic in Camera Raw by selecting the Edit menu and selecting Photoshop. There is supposed to be a screen that comes up allowing me to choose if I want to use Camera Raw to perform the edits which is supposed to provide easier to understand and use options.

Tim’s Quick Answer: The screen that asks about editing the image in Photoshop only appears for non-raw image files, not raw captures. It also only relates to Photoshop rather than Camera Raw, though you could use Camera Raw as a filter once the image is opened in Photoshop.

More Detail: When you send a raw capture from Lightroom Classic to Photoshop using the Edit > Edit In > Edit in Adobe Photoshop command, you will not be prompted about how you want to process the image. Instead, the raw image will be processed based on any adjustments applied in the Develop module and then saved as a TIFF or PSD file based on the settings established on the External Editing tab of the Preferences dialog in Lightroom Classic.

If you send a non-raw image (such as a PSD, TIFF, or JPEG image) you’ll be prompted about whether you want to create a new derivative copy of the image or simply edit the source (original) file you’ve selected.

However, in both cases the image will not open directly in Camera Raw before opening in Photoshop. That’s because the Develop module in Lightroom Classic is the equivalent of Camera Raw, and therefore Camera Raw is not needed to process the image. If it is a raw capture, for example, the raw will be processed to a TIFF or PSD file and therefore Camera Raw isn’t needed.

If, however, you want to use the Camera Raw interface to apply adjustments to an image that you’re working on in Photoshop (regardless of whether it was sent from Lightroom Classic or opened directly) you can use the Camera Raw filter by choosing Filter > Camera Raw Filter from the menu.

Today’s Question: Every time I launch Adobe Bridge I now get a message saying that Bridge would like to access data from other apps. I click “Allow” each time, but is there a way to get the message to go away?

Tim’s Quick Answer: This error message indicates that Adobe Bridge does not have full access to the hard drive. By enabling access, you will no longer see the message, and Bridge will be able to browse and update all files.

More Detail: The issue reflected in today’s question only affects Macintosh users, not Windows users. It relates to a security setting that selectively enables applications to access hard drives with full read and write privileges.

To resolve this issue, first click the Apple logo at the far left of the menu bar and choose System Settings. In the System Settings dialog scroll down on the left side and choose Privacy & Security. On the right side choose Full Disk Access, locate Adobe Bridge on the list, and turn on the toggle switch to the right to enable access for Bridge.

If you don’t see Adobe Bridge on the list, click the plus (+) symbol at the bottom-left of the list. In the dialog that appears you’ll be browsing the Applications folder. Open the Adobe Bridge folder and then either double-click on the Adobe Bridge application or select Adobe Bridge and click the Open button. This will add Bridge to the list, with Full Disk Access enabled.

Once the Full Disk Access option is enabled for Adobe Bridge, you’ll no longer see the message about accessing data from other apps when you launch Bridge.

Today’s Question: Is it really true that it is totally safe to delete the previews file for a catalog in Lightroom Classic? Is there no problem at all caused by doing so?

Tim’s Quick Answer: Yes, it is perfectly safe to delete the file that contains your standard previews for Lightroom Classic. The only drawback is that the experience of browsing your photos will be slower due to the lack of previews, though they will be generated as you work.

More Detail: You can think of the previews for photos in your Lightroom Classic catalog as being merely a cache that helps improve browsing performance. When standard previews have been generated for photos, it is much faster to browse those images in the Library module because the smaller JPEG previews can be loaded rather than rendering based on the full raw capture, for example. Without previews, you might initially see no image at all, then a low-resolution image based on an embedded preview, and then a normal image once the standard preview has been created.

As a result of the previews being a cache for improved performance, it is perfectly safe to delete the file containing the standard previews. For example, you may need to quickly recover hard drive space or there may be issues with corrupted previews.

If you want to delete the previews file, first navigate to the folder containing your catalog. From within Lightroom Classic you can go to the Catalog Settings dialog (from the Edit menu on Windows or the Lightroom Classic menu on Macintosh) and select the General tab. Click the Show button to the right of the displayed path for the catalog files, which will bring up a window in your operating system with the folder containing your catalog files highlighted.

Open the highlighted folder, and look for the file that has the same base filename as the primary catalog file (that’s the one with the .lrcat filename extension), but with “Previews” appended to the base filename. For example, if your primary catalog file is named “My Lightroom Classic Catalog.lrcat” the file containing the standard previews will be called “My Lightroom Classic Catalog Previews.lrdata”.

I recommend that you first quit Lightroom Classic, at which point you can delete that previews file. Don’t forget to empty the Recycle Bin (Windows) or Trash (Macintosh) to actually free up the hard drive space from the deleted previews file.

You can then launch Lightroom Classic again. Just note that initially there won’t be any previews available, but they will be generated as you browse your photos. That will cause the browsing experience to be slower until previews have been built. For example, if you browse a folder and wait for Lightroom Classic to generate previews for all images in that folder, the browsing experience will be fast again. But when you navigate to another folder that doesn’t have previews yet, the browsing will be slower until previews have been built.