HDR versus Tone Mapping

Today’s Question: How would you differentiate HDR from tone mapping?

Tim’s Quick Answer: Tone-mapping is actually one of the steps involved in creating an HDR (high dynamic range) image, but it is also possible to use tone-mapping adjustments on a non-HDR capture to produce a creative effect for the photo. So in general I would say that HDR is a process for assembling multiple exposures into a single image, and tone-mapping is a process for applying adjustments to a photo, including for HDR images.

More Detail: And HDR image is a high dynamic range image that is generally assembled from multiple individual exposures. When you assemble multiple exposures into the initial HDR image, the result is generally a 32-bit per channel image (or sometimes a 16-bit floating point image. In both cases the result is an image that contains a much greater range of tonal values than can be presented in a “normal” 8-bit or 16-bit per channel image.

Once you’ve created the initial HDR image, the next step is to perform a tone-mapping adjustment. This step essentially takes the extreme range of tonal values in the initial HDR image and maps them to a “normal” range of tonal values, generally producing a 16-bit (or 8-bit) per channel image as the final result.

Often you will perform the tone-mapping adjustment as a step in the overall process of creating the final HDR image, but this step can also be performed separately. For example, you could send a set of photos to Photoshop in order to make use of HDR Pro to create a 32-bit per channel HDR image, and then you could use the Develop module in Lightroom to apply the tone-mapping to that HDR image.

It is also possible to apply the same tone-mapping adjustments to a non-HDR image. You won’t magically create a greater dynamic range in the image, but you can create the impression of greater dynamic range by darkening down the highlights and brightening up the shadows, for example.

So, if you want to create an image that contains the full range of tonal values in a scene that contains too great a range to be captured in a single image, you’ll need to produce a “true” HDR image by capturing multiple exposures at different exposure settings. Regardless of whether you’ve captured a “true” HDR image or a single capture, you can still generally apply tone-mapping to the image to apply various adjustments.

But again, it is important to keep in mind that the only way to expand the true dynamic range of an image is to assemble multiple captures into an HDR result. Just because you apply tone-mapping to a photo doesn’t mean you have automatically expanded the dynamic range represented in the image.

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Don’t Delete?

Today’s Question: I remember a long time ago I heard you say that you don’t delete photos. Is that still true (if it ever was)? It seems to me that deleting photos is necessary to avoid filling up a hard drive with photos I’ll never use.

Tim’s Quick Answer: It is true that I almost never delete photos, but I certainly don’t recommend that all photographers adopt this approach. It is an approach that I prefer to take, but that isn’t right for all photographers.

More Detail: There are certainly situations where I will delete photos. For example, if I have captured an image that is clearly bad (such as when I press the shutter by mistake while walking with my camera) I will often delete that photo at that time if I am not in a hurry and am not photographing a subject that requires my attention.

I will also sometimes delete photos after I’ve imported my images into my Lightroom catalog, such as when an accidental capture was made with the lens cap on.

But in most cases I don’t bother taking the time to delete my outtakes. Instead I identify my best images from a photo shoot (in my case using star ratings) and then filter my images by star rating so that at any given time I am only looking at my best photos.

This approach enables me to retain all of my outtakes as “just in case” images that can be used if I decide one of my favorites from a photo shoot exhibited a particular problem. It does cause me to have more photos in my catalog (about 300,000 and counting) than I really need, and to fill up my “photos” hard drive (currently 4 terabytes) faster than I otherwise would.

It is important to keep in mind that my decision not to generally delete photos is really a philosophical decision. I have simply found over the years that I prefer to keep (nearly) all photos I capture, and then filter those photos based on specific attributes so I’m only viewing a relatively small number of photos at any given time.

For those interested in exploring this topic further, and learning more details about why I don’t generally delete photos, you can read my article “To Delete or Not to Delete” in the February 2013 issue of Pixology magazine. If you’re a current subscriber and missed that issue, you can send an email to renee@timgrey.com and she will be happy to send you that back issue. And if you’re not already a Pixology subscriber, you can sign up now and request this back issue (and others) at no additional cost.

You can learn more about Pixology magazine here:

http://pixologymag.com/

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Background Eraser

Today’s Question: I saw a tutorial about the Background Eraser tool in Photoshop, and it seemed like a good tool for creating composite images. I’ve never heard you talk about this tool. Is this a tool you recommend for compositing?

Tim’s Quick Answer: No! I do not recommend the use of the Background Eraser tool in Photoshop, because it is a destructive tool (meaning it removes pixels permanently). Instead I recommend using a layer mask to achieve the same basic result.

More Detail: In theory you could use the Background Eraser tool on a copy of the Background image layer, in order to create a non-destructive workflow using a “destructive” tool. However, I consider a workflow employing a layer mask to be much more flexible.

The basic approach in this case involves creating a selection of the area you want to keep in the final image, so that the area to be removed (or in this case just hidden) is not selected.

For example, you could use the Quick Selection tool to select the area to keep, or select the area you don’t want to keep and then invert the selection by choosing Select > Inverse from the menu.

You can then select the layer you want to hide pixels from. If that layer is the Background layer, double-click on the thumbnail for the Background image layer on the Layers panel to convert this layer to a normal layer. Then click the “Add a Mask” button (the circle-inside-a-square icon) at the bottom of the layers panel to add a layer mask to the current layer based on the current selection.

You can then, of course, continue fine-tuning the layer mask for your final effect, such as by painting on the layer mask with black to block pixels or white to reveal pixels.

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Recovering Photos

Today’s Question: My hard drive with all my photos died. The catalog was not affected. I can see the previews in the Library module. I have backup photos and would like to load the backups into the same folder that they were in before. The question is how to synch the catalog with the backup photos?

Tim’s Quick Answer: All you need to do in this case is restore the backup copy of your photos so those backup copies appear in the same “path” as the originals. Once you’ve accomplished this, Lightroom will recognize those photos as appearing exactly where they are expected.

More Detail: If the backup copies of your photos represent an exact duplicate of your original photos, this process is actually very straightforward. This is the primary reason I advocate for a synchronization approach to backup, as outlined in an article that appeared in the September 2014 issue of my Pixology magazine (http://www.pixologymag.com).

When you have a backup that is synchronized with the master copies of your photos, the only step you need to perform to use the backup copy as the new master copy is to have the hard drive on which that backup appears match the path of the original hard drive that failed. In other words, for Macintosh users you can simply change the volume label (the name) of the drive to match the original hard drive. For Windows users, you simply need to assign the same drive letter to the backup as had been used for the master copy of your photos.

If you have used an approach to baking up your photos that does not provide an exact copy of the master storage location, your task may be a little more complicated. But ultimately you simply need to make sure that the path to the hard drive, the folder structure, and the photos within that folder structure all match the original master hard drive. As long as you recover your backup photos so they appear in the same location from Lightroom’s perspective, you can simply open your existing catalog and all of your photos will be available.

Of course, it is also worth noting that once you’ve restored your photos from a backup, you want to be sure to create an additional backup of your photos as quickly as possible!

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Removing Old Versions

Today’s Question: How many copies of Lightroom do I have to keep on my hard drive? I still have version 4 and 5 installed on my hard drive. The nice folks at Adobe told me not to uninstall them???

Tim’s Quick Answer: Once you have confirmed that the latest version of Lightroom is installed and working properly (including ensuring that all of your plug-ins, presets, and other customizations available), from my perspective you can most certainly uninstall older versions of Lightroom.

More Detail: I imagine the only reason a support representative at Adobe would have recommended that you keep older versions of Lightroom installed was to take a cautious approach to “upgrading” to the latest version of Lightroom.

I am also very cautious about ensuring the latest version of Lightroom is working properly before removing older versions of Lightroom, but I am also eager to remove older versions of Lightroom since the application all by itself (even without your catalog files) consumes over a gigabyte of hard drive storage space. The “extra” copy of your catalog (since you would have upgraded your Lightroom 5 catalog to Lightroom 6, for example) is also consuming additional storage space.

While I’m always interested in having backup copies of my important photos and data, I am also interested in reclaiming hard drive storage space that is no longer necessary.

The key is to make sure that everything is indeed working properly in the latest version of Lightroom before removing older versions. For example, I would want to make sure that all plug-ins are working properly from Lightroom 6, and that I’ve migrated all of my presets and templates, for example.

But once you have everything configured properly (and tested) with the latest version of Lightroom, I certainly recommend removing any older versions of Lightroom. Of course, I also recommend that once you believe everything is working properly with the latest version that you wait for at least a few days (or more) just to be on the safe side.

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Catalog Cleanup

Today’s Question: I have never been able to get my Lightroom catalog correct when upgrading. It started when I upgraded from Lightroom 3 to Lightroom 4, and now is a real mess with Lightroom CC. When I upgraded to Lightroom 5, I tried to fix it but never got it right. It was always “I’ll fix it later”. It is time to get it right. I still have my catalogs from Lightroom 2 up through Lightroom 5. All my photos are on one external drive (backed up on a second external drive). How can I get all of my catalogs to be on one master catalog?

Tim’s Quick Answer: This is essentially a two-step process, though I should caution that while the process isn’t terribly complicated it is critical to pay close attention to detail to ensure good results. In short, you want to first upgrade any older (and still relevant) catalogs to the latest version of Lightroom (6/CC in this case). Then import the images from all “other” catalogs into your “master” catalog.

More Detail: Upgrading a catalog from an older version of Lightroom to the latest version of Lightroom is a simple matter of opening each “older” catalog with the latest version of Lightroom. You can launch Lightroom CC/6, then choose File > Open Catalog. Select the “lrcat” file for the older catalog you want to upgrade, and click the Open button. You’ll be prompted that the catalog needs to be upgraded, and when you confirm a new catalog will be created. In other words, you’ll have a new version of that catalog that is compatible with Lightroom CC/6, as well as the original version of the catalog that can serve as an additional backup.

Once you have upgraded all of the catalogs, you can merge them all into a single master catalog. To do so, open the master catalog in Lightroom. Then choose File > Import from Another Catalog and choose the catalog you want to merge with the master catalog. Using this option you can merge all of your “other” catalogs into your master catalog. At that point you can move all of the “other” catalogs to a backup location to avoid confusion, and make sure that you only work with your master catalog in Lightroom from that point forward.

The key to merging multiple catalogs is to take a deliberate approach and to pay attention to which catalogs need to be merged (and which have already been merged). You can read more details about this process in the article “Merging Catalogs” in the April 2013 issue of Pixology magazine. If you’re not already a subscriber, we’d be happy to provide you with all of the back issues at no additional charge if you choose to subscribe. You can sign up at http://pixologymag.com.

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Quick Selection is Slow

Today’s Question: My Quick Selection tool on Photoshop CC is very slow. I have 16GB of memory. It is so slow that it is difficult to use at all. Do you have any suggestions??

Tim’s Quick Answer: There are a few things I would do to help improve this issue, but I think the most important may be to adjust the Performance settings in Preferences.

More Detail: First, I would adjust the cache settings on the Performance page of the Preferences dialog. You can bring up this dialog by going to the menu and choosing Photoshop > Preferences > Performance on Macintosh or Edit > Preferences > Performance on Windows. Set the Cache Tile Size option to 1024K, and the Cache Levels setting to 6.

Once you’ve established these settings, click OK to close the Preferences dialog and restart Photoshop. Test whether this has resolved the issue with the Quick Selection tool.

If you are still experiencing an issue, I would also try to clear the preferences altogether. There are a variety of issues caused by corrupted preferences files. To reset, quit Photoshop and then prepare to hold the Command, Option, and Shift keys on Macintosh or the Ctrl, Alt, and Shift keys on Windows. Launch Photoshop, and immediately (while Photoshop is still loading) press and hold the keys referenced here on the keyboard. Click “Yes” in the confirmation dialog that appears, and test the results. Note that this process will cause the settings in Preferences and Color Settings to be reset to their defaults, so you’ll need to re-establish your preferred settings after performing this task.

If the issue still hasn’t been resolved, I would then disable GPU acceleration. To do so, turn off the “Use Graphics Processor” checkbox on the Performance page of the Preferences dialog. It is very much preferred to have this option turned on in order to maximize performance, but in some cases this setting can cause problems. If turning off this option improves the issue, I would highly recommend updating the drivers for your display adapter, and see if you can then enable GPU acceleration again without any problems.

A last recourse would be to uninstall and reinstall Photoshop, but I suspect one of the above steps will resolve the issue.

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Version Numbers

Today’s Question: My Adobe Creative Cloud subscription upgrade says Lightroom CC 2015. You call it Lightroom 6, but my program says 5.7.1. Why this confusion?

Tim’s Quick Answer: The latest version of Lightroom is referred to both as Lightroom 6 and Lightroom CC, depending on whether you purchased a standalone license for the software or subscribed via the Creative Cloud, respectively. If you’re seeing a version number earlier than 6, that indicates you’ve not yet installed (or aren’t properly running) Lightroom 6.

More Detail: It sounds like you have found Lightroom CC (aka Lightroom 6) within the Creative Cloud application, which is how you can install this latest version. If you haven’t yet installed Lightroom CC, you can simply click the “Install” button within the Creative Cloud application to have the new version installed.

I suspect in this case you may very well have installed Lightroom CC, but you’re still running Lightroom 5. This is a common source of confusion, because installing a “full” upgrade version of Lightroom (such as from version 4 to 5, or from version 5 to 6) isn’t actually updating your existing installation. Instead, a completely new copy of Lightroom is installed.

In other words, when you install Lightroom CC (version 6) you’ll still have Lightroom 5 installed on your computer. Once you’ve upgraded your Lightroom 5 catalog for use in Lightroom 6 (which again will make a full copy of the catalog rather than replacing your existing catalog), you will want to be sure to launch Lightroom 6 rather than Lightroom 5.

For example, you may want to create a new shortcut for Lightroom 6 to replace any shortcuts for Lightroom 5, to be sure you’re always running the latest version of the software. And once you have Lightroom 6 up and running and have confirmed everything is working properly, you can uninstall Lightroom 5 from your computer.

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Transporting Photos and Catalog

Today’s Question: I am about to go north and will be running Lightroom on a different desktop up there. Can I use the method to export (Export as Catalog) to an external drive and then connect Lightroom to that catalog, and photos, for use up north? Is this the best approach. Then I’d reverse the process when I return to Florida in the fall.

Tim’s Quick Answer: The “Export as Catalog” command (found on the File menu) can certainly be helpful for this approach, since this command causes both the selected photos and a catalog to be copied to a new location. If you already store your photos on an external hard drive you could also simply copy the catalog to that drive.

More Detail: The “Export as Catalog” command is very convenient, because it creates a copy of your catalog as well as your photos all in one process, copying all files to the destination of your choice. In this case, for example, that destination could be an external hard drive that can then be used to transport the photos where they are needed. The most important thing to keep in mind during this process is that you need to actually select all photos, without any filters applied that would limit which photos are being copied.

You could, for example, choose the “All Photographs” option from the Catalog section of the left panel in the Develop module. Then choose Edit > Select All from the menu (or press Ctrl+A on Windows or Command+A on Macintosh). Then choose File > Export as Catalog from the menu, and specify the destination location where you want to create a new catalog and copy all of the photos. Be sure the “Export negative files” checkbox is turned on so that the photos are actually copied during this process.

You can then simply connect the external hard drive to which you exported the images to the computer at the “other” location, and choose File > Open Catalog from the menu to open the catalog from that drive. You could also copy the files to a different drive as needed, but the point is that you now have a catalog and the photos in the same storage location, so those files can be accessed from another computer.

If the photos are already being stored on an external hard drive, you could also simply copy the catalog to that external hard drive and then open the catalog from that location. You can determine the location of the catalog files by first choosing Catalog Settings from the Edit menu on the Windows version of Lightroom or the Lightroom menu on the Macintosh version of Lightroom. Then go to the General tab and click the Show button to bring up an operating system window showing you the location of the catalog folder, with that folder highlighted.

You can then close Lightroom (so the catalog files won’t be in use) and drag-and-drop to copy the folder containing your catalog to the external hard drive. Just be sure to rename (or delete) the existing catalog folder so you won’t open that copy of the catalog by accident. In other words, if you are going to create multiple copies of a Lightroom catalog, you need to be careful to only use one copy as your “master” catalog, with any other copies becoming backup copies of the catalog.

The key in this case is to make sure that the photos and catalog files are accessible on the other computer. Copying both photos and the catalog to an external hard drive is a convenient approach, but it is also worth noting that this approach results in reduced performance for Lightroom. Therefore, if you’re comfortable with file management tasks, you may want to copy the catalog onto the internal hard drive of the computer, transferring those catalog files (along with the photos) to the computer at your destination whenever you are moving from one location to another.

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ND Not Neutral

Today’s Question: After reading a few comparative reviews on 10-stop neutral density (ND) filters, I purchased a Tiffen 77mm WW IR ND 3.0 as maybe the pick of the litter. Being new to 10-stop ND filters I tried it out taking two shots of the same white picket fence, one at 1/1000 of a second and one with the filter at 1 second. While, the histograms happily looked similar, the ND filter seems to have generated quite a large green cast.Any input would be appreciated.

Tim’s Quick Answer: There is certainly a degree of variability in terms of how neutral a neutral density filter really is, and this is especially true when it comes to very strong (such as ten-stop) ND filters. That said, I have had very good results with the top filters from Singh-Ray and B+W.

More Detail: As the strength (density) of a neutral density filter increases, it also becomes increasingly difficult to achieve a neutral result. Thus, for stronger ND filters I consider it especially important to spend the extra money for a top-quality filter. In my experience Singh-Ray filters generally produce the best results, but B+W filters also provide excellent results (generally at a slightly lower price point).

For relatively weak ND filters, it is not as challenging to achieve a neutral result, and so I think it is reasonable to opt for a less expensive alternative if that is your preference.

In any event, when using any ND filter there is some risk of color shift, and so I consider it critically important to take advantage of your camera’s RAW capture mode so you will have maximum flexibility in optimizing the color after the capture.

In most cases I find that the color shift caused by a neutral density filter is relatively linear and consistent, so correction during RAW processing is not generally problematic. My primary ten-stop ND filter is from B+W, and I find that this filter results in a slight to moderate warming of the photo that can easily be corrected with the Temperature and Tint controls during RAW processing.

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