Ask Tim Grey

Today’s Question: What is the impact of noise reduction in terms of the degradation of image quality?

Tim’s Quick Answer: Noise reduction can reduce the apparent sharpness and level of detail in a photo and can also cause colors to become less saturated and potentially bleed into surrounding areas within the image.

More Detail: Noise reduction essentially involves averaging neighboring pixel values in an image to reduce the appearance of noise. The specific process is a bit more complicated than this, but if you think about it as a process of averaging neighboring pixel values you can get a better sense of the potential degradation in image quality that can result.

Luminance noise reduction can be particularly problematic, because it involves averaging tonal values in an image. This can quite literally involve reducing contrast between neighboring pixels, which reduces perceived sharpness and can also result in a loss of fine detail. It is therefore critically important to be very careful when applying luminance noise reduction. You will need to compromise between the level of noise reduction being applied and the degradation in image quality.

With color noise reduction the risk relates to altering color values. With modest color noise reduction, the primary risk is that colors may become less saturated. However, with strong color noise reduction you can also create a situation where colors bleed into each other. For example, if you have a photo with vibrant green leaves on a tree set against a bright blue sky, along those edges you may see the greens blending into the sky and the blues blending into the leaves.

The key is to carefully evaluate the image, and to only apply enough noise reduction to mitigate the effect of the noise without using such strong settings that the image quality is significantly degraded.

Today’s Question: What do you mean by the term “demosaiced” for raw captures that are converted to the DNG file format?

Tim’s Quick Answer: Demosaicing refers to the process of calculating the “other” two color values for each pixel in a raw capture, since the vast majority of cameras only capture one of the three RGB values for each pixel.

More Detail: While each pixel in a digital image is typically made up of three color values (generally red, green, and blue for an RGB image), nearly all digital cameras only record a single color value for each pixel. Most cameras use a Bayer pattern, where for each set of four pixels on the image sensor one pixel only records the red value, two pixels only record green values, and one pixel records blue.

For a raw capture, that original data is recorded without calculating the “other” values for each pixel. If you capture a JPEG image the sensor still only captures one color per pixel, but the other pixel values are calculated in the camera to create the JPEG image with full color information for each pixel.

Whenever the raw capture data is processed, the additional values need to be calculated. The raw data represents mosaiced data, meaning there is a mosaic of values that don’t represent the complete RGB pixel values. The missing values for all pixels are calculated based on the values for neighboring pixels. This process of converting the mosaiced data into full color information is referred to as demosaicing.

Today’s Question: As a follow-up to your answer about working with images in tabs, one of the reasons I use floating windows is so I can drag a layer from one image to another, such as to make a composite. Is there a way to drag a layer from one image to another when they are all in tabs?

Tim’s Quick Answer: Yes, you can drag an image layer to another image in a tab by hovering the mouse pointer over the tab for the destination image as part of the drag-and-drop operation.

More Detail: When you have more than one image open as floating windows it can be a little easier to drag a layer from one image to another, since you can see multiple images at one time. However, as noted in my answer on Monday, having images opened in windows rather than tabs can be a bit cumbersome.

Fortunately, it is quite easy to drag a layer from one image to another even when the images are all opened in tabs.

To get started, select the tab for the image that contains the layer you want to copy to another image that is also open. On the Layers panel click and hold the mouse button on the thumbnail for the layer you want to copy to another image that is open in another tab. Keeping the mouse button held down, hover the mouse pointer over the tab for the image you want to copy the layer to. After hovering for a moment, the image represented by the tab will come to the forefront.

You can then continue dragging until the mouse pointer is over the destination image. If you want to center the image into the destination document hold the Shift key on the keyboard. Then release the mouse, and the layer you dragged from the source document will be copied to the destination image.

Note that you can select more than one layer if you want to copy multiple layers in one drag-and-drop operation. It is also worth noting that the layer will be placed in the destination document directly above the currently selected layer on the Layers panel. You can drag the layer into a different position on the Layers panel after copying it, but you can also ensure it goes where you want it by selecting the layer that you want the new layer to be positioned above in the destination document before dragging-and-dropping from the source document.

Today’s Question: Why does the Denoise with AI feature in Photoshop [via Camera Raw] cause the result to be saved as a new DNG file? Is the “old” way with Noise Reduction slider still available but hidden somewhere?

Tim’s Quick Answer: If you don’t want to use the Denoise feature in Camera Raw or Lightroom you can indeed use the Manual Noise Reduction option so you can control the noise reduction effect yourself.

More Detail: With some of the advanced features in Lightroom and Camera Raw, such as Denoise and Super Resolution, the processing requires that the raw capture data be processed and demosaiced. As part of this process the image is saved as an Adobe DNG file.

The new Denoise feature leverages artificial intelligence (AI) to process the image, and involves using just a single slider for the overall strength of the effect. If you prefer to use the manual noise reduction (as I do for most images) you can simply make use of the Manual Noise Reduction feature.

If the sliders for Manual Noise Reduction are not shown, you can click the triangle to the right of that heading to display them. This includes sets of sliders for both luminance and color noise reduction, which you can fine-tune based on the image and your preference in terms of balancing noise reduction with the potential degradation in the image that noise reduction can cause.

Today’s Question: When I open an image in Photoshop it “nests” behind my toolbar hiding the close or minimize buttons. Do you know of a fix for this?

Tim’s Quick Answer: You can force images to open into a tab rather than a floating window in Photoshop by turning on the “Open Documents as Tabs” checkbox in Preferences.

More Detail: While Photoshop enables you to open images in floating windows, doing so can often lead to issues where parts of the window or of the Photoshop interface are blocked. Having your documents open in tabs helps avoid this issue, and in my view streamlines the process of working with images in Photoshop.

If you already have open documents that are in windows, you can consolidate all of them to tabs by going to the menu and choosing Window > Arrange > Consolidate All to Tabs.

To have Photoshop always open images into tabs rather than floating windows, you can enable an option in Preferences. Start by choosing Edit > Preferences > Workspace from the menu on Windows, or Photoshop > Settings > Workspace on Macintosh. On the Workspace tab of the Preferences dialog turn on the “Open Documents as Tabs” checkbox in the Options section. This will cause all new documents or images you open to be opened in tabs rather than as floating windows.

You can then switch between open images by clicking on the applicable tab, similar to how you might switch between tabs in a web browser. This makes it convenient for working with multiple images, while also making it more streamlined even when only working with a single image.

Today’s Question: When editing JPEGs that I used in my early days of digital photography I’ve always opened them in Photoshop and used “Save As” to get a TIFF file and then edited from there. Is that not a good option?

Tim’s Quick Answer: Saving a JPEG image as a TIFF file before editing is a good approach, as it ensures you won’t create additional degradation of the image by saving multiple times with JPEG compression.

More Detail: JPEG images exhibit visible artifacts based on the way JPEG compression works. This can lead to a somewhat obvious grid pattern in the image, which can be distracting. The pattern is often quite difficult to see, but once you notice it you may find it difficult to ignore.

If an image was captured or saved as a JPEG, there will always be a degree of artifacts from the JPEG compression that you really can’t do anything about. In other words, saving a JPEG file as a TIFF won’t remove the JPEG artifacts, it will simply prevent them from getting worse.

Each time you make changes to a JPEG image and save it again, the JPEG compression algorithm processes the image data, which can lead to further degradation of image quality. It is therefore best to avoid saving updates to a JPEG image when applying adjustments, in the interest of maintaining maximum image quality.

Saving the JPEG as a TIFF image either without compression or with a lossless compression option (such as ZIP or LZW) will ensure that additional image degradation will not occur from compression, since no additional lossy compression is being applied after that point.

Of course, as a result of saving the image as a TIFF file the file size will be significantly larger. For example, a JPEG image that might be less than two megabytes in size might translate to a TIFF image of around twenty megabytes. In other words, you’ll be consuming quite a bit more storage space when saving a TIFF based on a JPEG image. This is certainly something to consider, especially since the reality is that if you use a high setting for the Quality option when saving an updated JPEG file, the degradation in image quality is quite minor.

Today’s Question: Now that Lightroom Classic has this new AI Generative Remove feature, should I be using that instead of Generative Fill in Photoshop?

Tim’s Quick Answer: While you can certainly use either Generative Remove in Lightroom Classic or Generative Fill in Photoshop, I prefer to use Generative Remove in order to streamline my workflow, only sending images to Photoshop when I can’t achieve my goals for an image in Lightroom Classic.

More Detail: Over time, new features have been added to Lightroom Classic to the point that there are fewer reasons to send an image to Photoshop. There are certainly still reasons you may want to leverage Photoshop in a workflow that revolves around Lightroom Classic, but I would say that AI-based cleanup no longer needs to be on that list.

The addition of the Generative Remove feature in Lightroom Classic means you can perform advanced image cleanup work based on artificial intelligence (AI) technology right from within Lightroom Classic. This feature is very similar to the Generative Fill command in Photoshop, with the key difference being that in Lightroom Classic you paint over the area you want to work on while in Photoshop you use a selection for this purpose.

There’s no need to favor one of these options over the other in terms of the quality of the results. Therefore, I recommend making the decision based on preference and workflow. If you don’t have any other reason to send the image to Photoshop, I would perform all the work in Lightroom Classic. If you have a reason you want to send the image to Photoshop, you can choose whether you want to use Photoshop or Lightroom Classic for the AI-based cleanup depending on which tool you find you are more comfortable using.

Today’s Question: I was wondering why every time I go to import new images into the Lightroom Classic catalog the images keep moving around. I have sorted by capture time, but it still is happening.

Tim’s Quick Answer: When you initially select a source of photos in the Import dialog the photos will load in the order they are read from the card, but when all photos have been found they will settle on the order you’ve selected from the Sort popup.

More Detail: Lightroom Classic provides several options for how you want your photos sorted. In the Library module, for example, you can set the sort order using the Sort popup on the toolbar below the image preview area. Similarly, you can set the sort order for the grid view in the Impot dialog, which can be helpful when reviewing the photos you’re about to import. For example, I most often prefer to use the “Capture Time” option for the sort order, so that I’m able to review the photos in the same order they were captured.

However, when you initially select a source of photos in the Import dialog, you’ll likely see that the sort order for thumbnails seem to constantly change, bouncing around in a seemingly random fashion.

The issue here is that the thumbnails are being added to the preview area as they are read from the card, and the images are not necessarily read from the card in the order they were captured. This is in part due to how images are saved to a media card in the first place, which involves writing data in what may seem like a bit of a random pattern on the card.

The result is that images are not read from the card in the order you might expect. As the images are read, they will populate the grid view in the Import dialog. Depending on the speed of your computer and the memory card, it may take a few moments for all the images to be located and therefore it may take a little time before all thumbnails are displayed.

Therefore, as the images are read, they will initially appear in the order in which they were read from the card, but then their order will update based on the option you’ve selected from the Sort popup. As soon as all images have been read so that all thumbnails are displayed, the thumbnails will stop changing their sort order, settling on the final sort order based on all images being displayed in the order you’ve selected.

This behavior can be a little distracting, and so I recommend just ignoring the images while you give Lightroom Classic time to locate all images, then finalize your settings for the import and click the Import button to complete the process.

Today’s Question: We just replaced an external hard drive with a new larger drive. The old hard drive is called “LaCie 2 Big”. I want to call the new one “Master Drive”. How do we change the name on the new drive without losing photos and info in Lightroom Classic?

Tim’s Quick Answer: You can rename the drive on Macintosh (or change the drive letter on Windows) through the operating system, and then use the “Find Missing Folder” command in Lightroom Classic to reconnect the top-level folder associated with your photo storage.

More Detail: Under normal circumstances, you should make all changes related to your folder structure from within Lightroom Classic, not through the operating system. However, if you need or want to change the address for a hard drive (via the volume label on Macintosh or drive letter on Windows) that needs to be done outside of Lightroom Classic.

When migrating to a new drive the first step is to copy everything from the existing drive to the new drive, making sure to match the folder structure perfectly. You can use a temporary backup job with software such as GoodSync (https://www.timgreyphoto.com/goodsync), for example, to help ensure this step is performed accurately and completely.

You can then disconnect the existing drive and make sure the new drive is connected, updating the volume label or drive letter as desired for that drive. This, of course, will cause all folders and photos to be missing in Lightroom Classic.

At this point you simply need to reconnect the hard drive within Lightroom Classic. To get started, make sure the root (top) level of the hard drive is shown as a folder at the top of the folder list under the heading for the drive in the Folders section of the left panel in the Library module. To do so, right-click on a top-level folder and choose “Show Parent Folder” from the popup menu. Repeat this command until you get to the top level where a folder appears representing the hard drive.

You can then right-click on the folder representing the hard drive and choose “Find Missing Folder” from the popup menu. Navigate to the top level of the hard drive to choose that as the location to reconnect. After reconnecting, which will cause all subfolders to reconnect, you can hide the parent folders as desired by right-clicking and choosing “Hide This Parent” from the popup menu.

Today’s Question: Generally speaking, what contributes more to the sharpness of one’s images, the quality of the camera or the quality of the lens?

Tim’s Quick Answer: In general, I would say that the lens has a more significant impact on image quality than the camera, especially in terms of the latest camera models.

More Detail: Both the camera and the lens have an impact on image quality, but I would say the choice of lens is more important than the choice of camera, all things considered. In other words, if you were going to invest a bit more money in one over the other, I would prioritize getting lenses of higher quality before opting for a better camera.

Of course, there are many variables to consider when it comes to cameras and lenses. For example, if you tend to print your images very large, then investing in a camera with greater resolution and overall image quality can certainly be beneficial.

These days, however, most cameras offer adequate resolution and image quality for printing images at relatively large sizes. Therefore, I would say that the choice of lens is going to have a greater impact on image quality for most photographers. That’s not to say that the choice of camera isn’t important, but that the choice of lens is often going to have a greater impact.

Most lenses offer very good image quality and resolution these days. But there are still considerable differences between the very best lenses and the lower-end lenses. Therefore, if you’re trying to optimize image quality especially in the context of making large prints, I would start by choosing the best lenses you can afford.

You still want to make sure you’re capturing images at an adequately high resolution for the size output you typically create, but I would prioritize lens choice over camera choice if you had to choose one over the other.