Author: Tim Grey

Today’s Question: How can I tell if an image is raw? I know that the file extension can be helpful to tell if a file is in raw format. Usually. But what if I do something like export a JPG file to DNG from Lightroom Classic? And then I import a different Canon raw capture as a DNG. How can I look at the two DNG files and determine which one is a true raw image?

Tim’s Quick Answer: I don’t know of any software that makes the task of identifying the source of a DNG file particularly easy or reliable. However, you can open a DNG file with a text editor and search for an indication that the file was converted from a different file type.

More Detail: With a proprietary raw capture format, you can essentially just tell from the file type that the file is indeed a raw capture. The same is not true for an Adobe DNG (Digital Negative) file.

A DNG could be an original raw capture, as a variety of cameras support raw captures saved directly as a DNG file. You can also convert a proprietary raw capture to the DNG format, with the option to embed the original raw capture in the DNG file if you’d like. Both of these would provide you with a file that could be considered a raw capture.

However, it is also possible to convert other image file formats to DNG. You could, for example, capture a JPEG image with a smartphone and then convert that JPEG image to a DNG file. This represents a DNG created from a non-raw source, meaning there is full color information for all pixels in the image, unlike most raw capture formats. This type of DNG file is referred to as a Linear DNG.

If you open a DNG file with a basic text editor on your computer, you can search for the text “converted”. With the software I’ve tested (which in this case only includes Adobe software), a DNG file that was converted from another file format will include text in metadata describing the conversion. For example, a JPEG I converted to DNG includes the text “converted from image/jpeg to image/dng, saved to new location”.

Viewing a DNG file this way isn’t the easiest task, and you need to be very careful not to make changes to any of the text and save the modified file, as that can corrupt the image.

If any readers are aware of software tools that streamline the process of determining the provenance of a DNG file, please let me know and I’ll be happy to share that information.

Today’s Question: Why does it matter if I remove a photo storage card without ejecting it from my iMac and get this “Disk Not Ejected Properly” message?

Tim’s Quick Answer: The reality is that as long as data is not being written to the media card (or other storage device) there is virtually no risk of harm. That said, I do recommend playing it safe and using the option to safely remove storage media before disconnecting it from your computer.

More Detail: The risk involved with not ejecting or safely removing is that files (or the entire storage device) could become corrupted. This is really only an issue if data is actually being written to the storage device. If you disconnect a storage device while data is being written, the data will be written incompletely, and one or more files may be corrupted.

When you are downloading photos from a media card to your computer, data is being read from the card but not written to the card. Therefore, there isn’t any risk of corruption to the card since no data is being written to the card. In other words, no change is actually being made to the card itself.

That said, I do recommend using the option to eject or safely remove the media card using the applicable feature in your computer’s operating system. I simply consider this a good habit to be in, as it can help ensure you don’t ever disconnect a storage device while data is actually being written to it, even though that isn’t a concern when simply downloading photos from a media card.

Note, by the way, that in the Import dialog in Lightroom Classic there is a checkbox you can turn on that will cause the card to be safely removed automatically when the import is complete, so you don’t need to take the extra step of using the operating system feature when downloading photos.

Today’s Question: Did you happen to find a way to match Wratten numbers with HEX numbers or RGB values? For example, what is the HEX code of an 81A warming filter?

Tim’s Quick Answer: While I’ve not determined the specific color values of the original Wratten filters, you can get an approximate color value for some of them using the Photo Filter adjustment in Photoshop.

More Detail: Today’s question was a follow-up to an old article I wrote about fifteen years ago on the subject of photo filter effects with digital processing. In Photoshop, that means using a Photo Filter adjustment layer.

The Photo Filter adjustment in Photoshop provides the ability to add a color tint to an image, enabling you to mimic the behavior of some of the colored filters that were often used in film photography. In fact, some of the presets for the Photo Filter adjustment represent approximations of the effect from some of the standard warming and cooling filters.

You can also select any color you’d like from the Color Picker when using the Photo Filter adjustment. Start by selecting the desired preset from the Filter popup. For example, you can get a warming effect with the “Warming Filter (81)” option. This will change the color of the color swatch associated with the Color option, and you can click that color swatch to bring up the Color Picker dialog, showing you the color values for the filter you selected.

I have discovered that there is a slight problem with some of these presets, in that not all of them use proper color management. What that means is that for some of the filters you will get a different color depending on which color space you are working in. The differences are not too significant, however.

So, you can use this technique to determine Photoshop’s version of the color you would apply to achieve the approximate effect of certain color filters. In the Color Picker dialog you can see the actual color values for the selected filter. Note that you can also adjust the overall strength of the effect with the Density slider for the Photo Filter adjustment.

Today’s Question: I have a concern relating to the magnetic portion of the XUME Adapters you have recommended. Since it would be stored in my camera bag in close proximity to my memory cards, my hard drive and, worse yet, my camera with its internal computer memory, should I be concerned about the possible impacts of the magnetic fields? Or, is it weak enough that it would be of no concern?

Tim’s Quick Answer: Most of the items you mentioned use flash-based memory rather than magnetic storage, and so magnets would not be a concern. If your hard drive is a traditional drive (rather than an SSD) I would tend to keep the XUME Adapters at a distance, but the reality is that it takes a very strong magnet to cause problems for a hard drive.

More Detail: I am a huge fan of XUME Adapters (http://timgrey.me/go-xume), since they make it so incredibly easy to add or remove a filter (such as a solid neutral density filter) to the front of a lens.

These adapters employ magnets. One piece attaches to the front of a lens, and the other piece attaches to the filter. You can then simply put the filter in place at the front of the lens, and the magnets hold the filter in place until you choose to remove it.

The magnet in the XUME Adapters is adequately strong to hold a filter in place, but not strong enough that I would be concerned about it being near a hard drive. And flash-based media (such as memory cards or the memory buffer in your camera) would not be a concern at all.

By the way, you can see a (very old!) video of me demonstrating the use of XUME Adapters on my “Tim Grey TV” channel on YouTube here:

https://youtu.be/qfOdqsC457s

 

Today’s Question: Is there a way to run a batch process to update Photoshop PSD files with the Maximize Compatibility option? After synchronizing a folder in Lightroom Classic I have 30-40 files with the message to Maximize Compatibility in Photoshop first.

Tim’s Quick Answer: Yes, you can easily batch-process images to save as Photoshop PSD files with Maximize Compatibility turned on using the Image Processor feature of Photoshop.

More Detail: The Image Processor feature of Photoshop makes it easy to batch-process photos to save in a different file format or with different settings for the existing file format.

I recommend using Adobe Bridge to get started, as this makes it easier to locate and select the PSD files you need to process. You could, for example, browse multiple folders at once and set a filter to only show PSD files. Once you’ve located the PSD files you want to process, select them and then go to the menu bar and choose Tools > Photoshop > Image Processor.

The Image Processor dialog will then open automatically in Photoshop, and you can adjust the settings for processing. In section one you can keep the “Open first image to apply settings” checkbox turned on. In section two, choose the option to “Save in Same Location” (more on this in a moment).

In section three, turn on the “Save as PSD” checkbox, and turn off the checkboxes for JPEG and TIFF files. Under the “Save as PSD” checkbox, turn on the “Maximize Compatibility” checkbox. Make sure the “Resize to Fit” checkbox associated with the “Save as PSD” option is turned off.

In section four you can keep the “Run Action” checkbox turned off, and turn on the “Include ICC Profile” option.

Click the Run button, and Photoshop will open and re-save the images you had selected. Note, however, that the resulting files will actually be placed in a sub-folder below the folder where the source image is located. Therefore, you’ll need to move the photos from the PSD folder created by Image Processor back into the intended parent folder. You can either move the older versions of the PSD files in the parent folder to a backup folder first, or simply delete them once you’ve confirmed the new PSD files were saved properly.

Today’s Question: Since there is no “Maximize Compatibility” for TIFF files [in Adobe Photoshop], does that mean TIFF automatically creates the flattened composite layer? If TIFF files can maintain all Photoshop edits, automatically “maximize compatibility” (if, in fact, they do), and support compression to boot, is there any advantage to saving as PSD over TIFF?

Tim’s Quick Answer: Yes, you can think of TIFF files saved from Adobe Photoshop as effectively always having “Maximize Compatibility” turned on, whereas this is an option you can turn on or off for PSD files. So, you might say that the only reason you might prefer to save as a PSD file is if you want to be able to turn off Maximize Compatibility.

More Detail: In Photoshop you have the option to turn “Maximize Compatibility” on or off for Photoshop PSD files you save. It is necessary to turn on Maximize Compatibility in order to be able to import photos into Lightroom Classic, or to open those PSD files with software that support PSD files but not layers and other special features in Photoshop.

You might think of TIFF files saved from Photoshop as effectively always having Maximize Compatibility turned on. In other words, even if other software supports TIFF images but does not support the various layers and other special features in Photoshop, you would still be able to open a flattened version of that TIFF image using that other software.

In addition, TIFF files provides you with greater flexibility in terms of compression compared to PSD files. Therefore, now that Photoshop supports a layer-based workflow for TIFF images in a way that used to require saving as a PSD, my general preference is to use the TIFF file format rather than the PSD file format when saving images from Photoshop (including images sent to Photoshop from Lightroom Classic).

Today’s Question: In Lightroom Classic is there a way to reject a group of photos, so that I can delete them from Lightroom and the hard drive? I have lots of junk photos just wasting space.

Tim’s Quick Answer: Yes, you can very easily apply a Reject flag to multiple photos in the Library view in Lightroom Classic, and then quickly delete all rejected photos in a given folder or other location.

More Detail: The Reject flag in Lightroom Classic can be very helpful for deleting outtakes with an efficient workflow. While this approach adds an additional step compared to simply selecting and deleting photos, that extra step also provides an additional opportunity to make sure you really want to delete the applicable photos.

The first step is to mark photos that you’d ultimately like to delete with a Reject flag. This can be done with a batch of photos in the Grid view (thumbnails) display in the Library module. You can select multiple images at a time to make this process easier.

To select a range of images that are all in a sequence, click on the thumbnail for the first image and then hold the Shift key on the keyboard and click on the thumbnail for the last image in the sequence. To select images that are not in a sequence you can hold the Ctrl key on Windows or the Command key on Macintosh while clicking on the thumbnail for each photo you want to add to the selection.

After selecting multiple photos within the Grid view display, you can press the “X” key on the keyboard to assign a Reject flag to all of the selected images.

Once you’re finished reviewing a group of photos you can easily delete all images to which you have assigned the Reject flag. First, navigate to the location where you want to delete all photos that have a Reject flag. That could be a single folder, for example, or you could even go to the All Photographs collection in the Catalog section of the left panel in the Library module if you want to delete all photos with a Reject flag in your entire Lightroom Classic catalog.

Finally, go to the menu and choose Photo > Delete Rejected Photos. In the confirmation dialog that appears, click the “Delete from Disk” button so the images with the Reject flag with be both removed from the catalog and deleted from your hard drive.

Today’s Question: I would like to use a printing service for some large metal prints. The printer will only accept a file size under 32 megabytes, but some of the images I would like to have printed are in the 38 to 39 megabyte range. The printer’s suggested solution is to change the resolution to 150 pixels per inch. Yet the same printer suggests a minimum resolution of 300 pixels per inch for metal prints. I am wondering if I should gradually lower the resolution in the Lightroom Classic export process until the file is under 32MB. Would that work?

Tim’s Quick Answer: I recommend contacting the printer directly to convince them to allow you to send larger files, or to find a different printer who doesn’t place this limitation on file size.

More Detail: Granted, you can achieve good print quality at 150 pixels per inch, especially if the final image will be displayed in a location where viewers won’t be able to get right up to the print. And in fairness, a metal print does lose a bit of detail as part of the printing process, which makes it somewhat reasonable to use a resolution of 150 pixels per inch.

However, I recommend sizing images for printing at the highest resolution supported by the output process. In most cases for a metal print, that resolution would be around 300 pixels per inch.

I consider the file size limitation of 32 megabytes to be arbitrary and frankly silly. An image saved as a TIFF file in 8-bit per channel mode would exceed 32 megabytes at an output size of a little under 13-inches by 10-inches at 300 pixels per inch. That’s not what most photographers would consider a particularly large print.

You could reduce the file size a little more by using ZIP compression for the TIFF file, which is lossless compression. Otherwise, for large prints, the only way to get the file size down without compromising on resolution would be to save as a JPEG image file, which I consider to be a bad idea especially for large prints.

So, again, I suggest having a conversation with the printer to find a way to submit a larger file size, or finding a printer that is able to accept file sizes commensurate with the output size being produced.

Today’s Question: I know you can use virtual copies in Lightroom Classic to have different interpretations of a photo. But in Friday’s answer you made reference to metadata as well. Don’t virtual copies inherit the metadata of the original image?

Tim’s Quick Answer: When you create a virtual copy in Lightroom Classic it does inherit the metadata of the original photo. However, after creating a virtual copy new metadata updates are not synchronized between the original photo and the virtual copy.

More Detail: A virtual copy in Lightroom Classic is often thought of as providing the ability to create more than one interpretation of a photo in the Develop module. For example, the original image might be in color, and you might make a virtual copy for a black and white interpretation, and yet another virtual copy for a sepia-tone version.

However, a virtual copy is really a complete additional set of metadata for the source photo. So, for example, after creating one or more virtual copies for a photo you can assign different star ratings to each version of the image. You can also assign different keywords and other metadata for each photo. And, as noted above, you can apply different adjustments in the Develop module for each image.

In some ways this is very good, so that you can assign different star ratings to the different versions of the photo to help you decide which is your favorite version.

Of course, this can also be a little bit of a challenge. If you’re adding keywords later in your workflow, after you had already created one or more virtual copies, those keywords won’t propagate to all versions of the image. You would need to update the metadata for all versions of the image or synchronize that metadata after applying it to one version of the image.

To some extent you can think of a virtual copy as being a completely separate copy of the original image. Of course, in reality a virtual copy is simply an “extra” set of metadata that relates to the source image. But it is important to keep in mind that the metadata for a virtual copy can be different from the metadata for the source image.

Today’s Question: You answered a question from a photographer about switching from Lightroom Classic to Bridge, and you said that one of the information losses would be “virtual copies”. I routinely make one or more virtual copies for different processing decisions. Will those virtual copies and all the processing information be lost if I for some reason stop using Lightroom Classic? Is that information not saved in metadata somehow attached to the original file? Would I have to, in effect, export every one of my virtual copies to retain that processing data? If so, yikes!

Tim’s Quick Answer: You would indeed need to export your virtual copies if you were going to stop using Lightroom Classic and wanted to preserve those versions of your photos.

More Detail: A virtual copy in Lightroom Classic enables you to create more than one interpretation of a photo in terms of adjustments in the Develop module or metadata for the image. For example, you can optimize a color photo, then make a virtual copy and create a black and white interpretation of the same capture.

If you enable the option to automatically write changes to metadata for your photos (found on the Metadata tab of the Catalog Settings dialog), an XMP sidecar file will be created or updated for raw captures that you apply changes to within Lightroom Classic. However, that metadata is not saved outside of the catalog for virtual copies.

If you wanted to preserve the virtual copy version of the photo in the same way as the original raw capture with a sidecar file, you would need to export the virtual copy. In the case of a raw capture, if you export with the “Original” option selected from the Image Format popup, the original raw file will be exported along with an XMP sidecar file containing the metadata updates and adjustment settings.

In other words, you can create multiple copies of the same raw capture file (each with a unique filename of course) and you can have different XMP sidecar files for each, containing different adjustment settings.

Keep in mind that the adjustment settings included in the XMP sidecar file from Lightroom Classic are only usable in Lightroom or via Camera Raw in Photoshop. Other software tools would not be able to interpret those adjustment settings. So, if you were going to stop using Lightroom Classic as well as Photoshop, you would want to export your raw captures to TIFF files to preserve the appearance of the photos with a format that other software could make use of.