Ask Tim Grey

Today’s Question: How does the Tone Curve differ from the Basic panel tonal adjustments in Lightroom Classic?

Tim’s Quick Answer: The Tone Curve adjustment in Lightroom Classic (or Camera Raw) simply provides a higher degree of control over the adjustment and the tonal range affected compared to the tonal adjustments in the Basic section.

More Detail: I think one of the best ways to understand how the Tone Curve adjustment differs from the tonal adjustments in the Basic section of the right panel in the Develop module in Lightroom Classic (or in Camera Raw) is to recognize that in effect they are all the same adjustment. In other words, you can think of the sliders for Highlights, Shadows, Whites, and Blacks as each representing a specific adjustment with the Tone Curve. I’ll quickly add the important caveat that there are other differences, but this analogy can help make it more clear how the Tone Curve differs.

For example, if you increase the value for the Shadows slider you are effectively moving an anchor point upward toward the dark (left) end of the Tone Curve. In both cases the shadows would be brightened. Reducing the value is the same as lowering the anchor point, darkening the shadow areas of the image.

If you switch the Tone Curve to the Parametric mode, the two categories of adjustments become even more clearly similar. In the Parametric editing mode for the Tone Curve you have sliders for Highlights, Lights, Darks, and Shadows, which roughly (but not exactly) correspond to the tonal adjustment sliders in the Basic section.

The real power of the Tone Curve adjustment when working in the Point Curve mode, however, is that you can fine-tune the range of tonal values you’re affecting and the specific impact in terms of brightness and contrast, by manipulating the curve shape using multiple anchor points. While this degree of fine-tuning control isn’t necessary for all images, it can certainly be very helpful to have the greater degree of control for sophisticated adjustments with certain images.

Today’s Question: When I import my photos into Lightroom Classic, after a brief delay the thumbnails for the images change. Sometimes the difference is rather significant. What causes this?

Tim’s Quick Answer: What you’re seeing is the difference between the preview embedded in the original capture by the camera and the interpretation of the image in Lightroom Classic. This same issue also affects other software such as Adobe Bridge.

More Detail: The preview you see on the back of your camera will generally differ from the preview you see when browsing the photos on your computer, in some cases in very significant ways. This is based on the difference between the previews rendered by the camera compared to different software applications.

There are two key issues when it comes to mismatched previews for raw captures on your camera versus the computer. The first is that adjustments applied in-camera don’t actually alter the raw capture, and so won’t be reflected in software on your computer. The second is that the camera serves as its own raw processing software and will render the previews differently compared to other software. Compounding this issue, different software will also generate different previews.

As a somewhat dramatic example, if you set your camera to a monochrome effect (black and white) for raw captures, the embedded preview for that raw capture will be black and white. That will cause the preview on the back of the camera to appear in black and white. However, as soon as you import the photo into Lightroom Classic (or browse it with other software) a new preview will be rendered, and the image will appear in color.

The same concept applies even when adjustments haven’t been applied, because the underlying raw processing is different in the camera versus using software on your computer.

The effect of this issue is that when you initially view the images on your computer, you’ll be seeing the embedded preview generated by the camera. However, shortly thereafter the software will update the preview based on its own rendering of the image, causing the preview to update accordingly. In some cases, the difference between the camera preview and the software rendering may be very subtle, but there will be a difference.

Today’s Question: I’ve read that circular polarizing filters were designed specifically for cameras with a mirror, such as a DSLR. But for cameras without a mirror, a linear polarizing filter is the better choice. Should I be using linear polarizing filters on my mirrorless camera?

Tim’s Quick Answer: You can use a circular polarizer for either type of camera, but you should avoid linear polarizers for digital SLR cameras due to the mirror.

More Detail: The real issue here is that a linear polarizing filter should not be used with a single-lens reflex (SLR) camera. The reason for this is that the beam splitting of the mirror on an SLR camera interferes with the phase-detection autofocus and metering. For this reason, only circular polarizing filters should be used with SLR cameras.

For mirrorless cameras you can use either circular or linear polarizing filters, because there isn’t a mirror for the linear polarizer to interfere with. However, to me the safest approach is to always choose a circular polarizing filter rather than a linear polarizing filter. In addition, circular polarizers are much more common, so they’ll be easier to find in general.

Today’s Question: Can you explain how you apply color balance adjustments using the Tone Curve in Lightroom Classic?

Tim’s Quick Answer: To apply color balance adjustments with the Tone Curve adjustment in Lightroom Classic you choose an individual color channel (Red, Green or Blue) and apply a curve that shifts the balance of color. That curve can be rather sophisticated to provide a different shift in the shadows, midtones, and highlights, for example.

More Detail: Today’s question is a follow-up from yesterday’s answer, where I mentioned that while I don’t use the Tone Curve adjustment in Lightroom Classic very often, it can be very helpful when I need to apply a sophisticated fine-tuning of the balance of colors in an image.

To get started, go to the Tone Curve adjustment and from the Adjust option at the top of the controls choose either the Red, Green, or Blue channel. Red controls the balance between red and cyan, Green controls the balance between green and magenta, and Blue controls the balance between blue and yellow.

For a very general color balance adjustment you could simply click to add an anchor point at the center of the curve line and then drag upward to shift the balance of colors toward the color represented by the channel, or downward to shift toward the opposite color.

However, the real power of using the Tone Curve adjustment to refine color balance is the ability to apply a variable effect for the shadows versus the highlights, for example. You could drag an anchor point downward toward the dark (left) end of the curve for the Blue channel to shift the color in the shadows toward yellow, for example. You could then drag an anchor point upward toward the bright (right) end of the curve to shift the highlights toward blue.

By creating more sophisticated shapes for the curve for each channel following the principles outlined above, you can shift the balance of colors in an image in very sophisticated ways. This can be very helpful, for example, when working on a photo that has challenging color due to a blend of various light sources, such as when there is natural light along with incandescent and fluorescent lights in the same scene.

Today’s Question: I was intrigued by your answer about not necessarily needing all the adjustments that are available in software such as Lightroom Classic and Photoshop. I was particularly interested to read that you would consider removing a couple of adjustments if given the choice, and would be curious to know what those are.

Tim’s Quick Answer: The primary adjustment I would tend to want removed from Lightroom Classic (or Camera Raw) would be the Grain option in Effects. I would also suggest removing the Pet Eye option for the from the Red Eye Correction tool, as in my experience it never works well.

More Detail: I enjoyed the philosophical discussion of whether we should perhaps limit ourselves to a relatively small number of adjustments for optimizing our photos in yesterday’s edition of Ask Tim Grey. As I noted, I appreciate having most of the adjustments available even if I don’t use them very often, but there are some I could live without.

I would be perfectly happy if the Grain option in the Effects adjustments were removed. While I have fond memories of film photography from my younger days, I never feel the need to add a film grain effect to photos. Overall, it tends to look more like luminance noise, so I’d just as soon avoid the effect even when I’m trying to mimic the look of an old film photo.

While I would generally say that the ability to remove retinal glare in photos of pets (the equivalent of red eye removal for photos of people), in my experience this feature works so poorly that I consider it useless. It is far more reliable to use blend modes in Photoshop to remove the pet eye rather than struggling with the Pet Eye option for the Red Eye Correction tool.

Otherwise, I would say that while there are many features I use very rarely in Lightroom Classic or Camera Raw, I do appreciate that the adjustments are there. For example, I almost never use the Tone Curve adjustment (called simply Curve in Camera Raw). However, every now and then I do appreciate the refined control it provides for both tonal and color balance adjustments.

Today’s Question: As all the various editing software continues to be updated, we have more and more adjustments available for our photos. Is there an argument to be made that we have too many options, and that we should perhaps consider limiting ourselves to the more basic adjustments?

Tim’s Quick Answer: Yes, there is most certainly an argument (perhaps more than one) that using fewer adjustments would be reasonable.

More Detail: As much as I love having options, I also think it would be reasonable to say that we have more options than we necessarily need when it comes to optimizing our photos. There are most certainly adjustments I never use, and even more that I use only rarely.

To some extent my opinion here might make me a bit old fashioned. I am, after all, a proponent of the long-held notion that the image should be created as close to perfect in the camera, so that minimal processing is necessary after the capture. I often find, however, that my favorite photos are those that don’t require much editing, because I’m mostly happy with how they were captured in the first place.

For the vast majority of my photos, I only need the basic adjustments related to tone and color, sometimes with a bit of fine-tuning for color such as with the Color Mixer and Color Grading adjustments in Lightroom Classic and Camera Raw.

I don’t find the need to use image cleanup tools very often, in part because I try to make sure my camera sensor remains free of dust spots, and because I try my best to avoid distractions and blemishes in my original compositions. I also don’t tend to need to use targeted adjustments (via masking, for example) for most of my photos.

Having said all that, I most certainly appreciate that all the adjustments are available. For example, it can be tremendously helpful to fine-tune the overall tonality specifically for the sky to help balance that area better with the rest of the photo. And while I do my best to avoid blemishes in my photos, sometimes they are unavoidable or I fail to notice them until after the capture.

So, I would not suggest that Adobe remove adjustments from Lightroom Classic or Camera Raw, perhaps with a couple exceptions. But I also think there’s something to be said for being sure not to over-process an image, and that just because a particular adjustment is available doesn’t mean it should be used for every image.

Today’s Question: I watched your presentation on customizing the interface in Photoshop, but ran into a problem right away where I couldn’t move any of the panels around. How to I enable that capability?

Tim’s Quick Answer: It sounds like you have the workspace in Photoshop locked, so all you need to do is choose Window > Workspace > Lock Workspace from the menu to turn it off. You’ll then be able to move panels around to reconfigure the workspace.

More Detail: One of the more helpful features of Photoshop is the ability to customize the interface based on your own preferences and the tools you tend to use most. You can even create more than one workspace to reflect different tasks, such as having one workspace for general image optimization and another for more advanced retouching work.

In addition to being able to save a custom panel arrangement as a workspace in Photoshop, you can enable the “Lock Workspace” option to ensure the workspace doesn’t get significantly altered. When you enable the “Lock Workspace” feature you can’t undock panels. However, you can still add additional panels via the Window menu, and you can move undocked panels around or close them. The menu command is found at Window > Workspace > Lock Workspace.

If you want to move panels around, such as to create a new workspace or modify an existing workspace, you can choose Window > Workspace > Lock Workspace first to unlock the workspace if it is locked. You’ll then be able to freely add, close, and move panels around.

Once you’ve configured the panel arrangement to your liking, you can save the workspace by choosing Window > Workspace > New Workspace from the menu. If you then want to make it so panels can’t be undocked, you can once again enable the “Lock Workspace” setting.

I covered the various options for customizing the interface in Photoshop in my “Ultimate Live Learning” presentation on “Configuring the Interface in Adobe Photoshop”. If you’re subscribed to my GreyLearning Ultimate Bundle you can sign in and then click the “Resume Course” button and find the lesson recording in the “Configuring Photoshop” chapter of the “Photoshop Ultimate Live Learning” course that can be found here:

https://www.greylearning.com/courses/photoshop-ultimate-live-learning

Today’s Question: As a follow up to your answer about scratch disks in Photoshop, is there a way to actually know if the scratch disks are even being used?

Tim’s Quick Answer: The only way to determine if Photoshop is making use of scratch disks is to monitor the status bar at the bottom of the interface after setting the popup to “Efficiency”.

More Detail: As noted in yesterday’s answer, Photoshop uses hard drive space to supplement memory (RAM) when there isn’t enough memory. The hard drives used for this purpose are referred to as “scratch disks” in the parlance of Photoshop.

Ideally, Photoshop never needs to use scratch disks, because when scratch disks are used in place of memory performance will generally be greatly diminished. This goal is achieved by ensuring your computer has adequate system memory (RAM). I recommend 32GB as a good balance for memory, though more can certainly be helpful if you work with particularly high-resolution images or need to have multiple memory-intensive applications running at once.

If you want to monitor whether Photoshop is supplementing memory by using scratch disks, you can monitor the Efficiency value. To get started, open an image in Photoshop and look at the status bar at the bottom of the screen. Click the right-pointing chevron (arrow) symbol toward the left side of the status bar, which will bring up a popup where you can select what information is shown to the right of the current zoom setting on the status bar. Select “Efficiency” from that popup.

At this point the status bar will show “Efficiency: 100%” to indicate the current efficiency level. If a number lower than 100% is shown, that indicates that there isn’t enough memory and the scratch disks are being used to supplement that shortage.

If you only rarely see the Efficiency value drop below 100%, such as when you’re working on an unusually large image, it isn’t anything to worry about. But if you’re regularly seeing a value below 100% for Efficiency it is time to either make sure no other applications are running when you’re using Photoshop or to upgrade your computer so you have more available memory. It is also worth confirming that you have allocated enough memory to Photoshop in this case. On the Performance tab of the Preferences dialog I recommend setting the “Let Photoshop Use” slider in the Memory Usage section to about 80%.

Today’s Question: I am getting a “Scratch Disk getting full” message when starting Photoshop. What do I need to do to fix this?

Tim’s Quick Answer: When Photoshop reports that the scratch disks are getting full, I recommend clearing space on the drive so that at least 100GB is available or changing the scratch disk settings in Preferences to exclude any drives that don’t have adequate free space.

More Detail: The term “scratch disk” in Photoshop refers to the use of hard drive storage space to supplement memory (RAM). Ideally, you’ll never get into a situation where Photoshop is using a scratch disk, because it means you don’t have enough memory for the current task. When Photoshop uses a scratch disk performance can be dramatically diminished.

The first step would be to check the settings for scratch disks in Preferences in Photoshop. On the Scratch Disks tab of the Preferences dialog, you’ll find a list of all hard drives currently connected to your computer. You can turn the checkbox for each hard drive on or off to select which can be used as scratch disks.

You must have at least one hard drive selected as a scratch disk, and I recommend using an internal hard drive (so that it is always available) that has at least 100GB of free space. If you have more than one internal hard drive, I recommend using the one that does not have the operating system and applications stored on it, to help improve performance.

You can also select more than one hard drive, including external drives. In general, I recommend selecting only drives that offer very good performance and with at least 100GB available. In this case, for example, it might make sense to disable the drive that doesn’t have much free space, selecting a different drive instead.

If one or more hard drives don’t have at least 100GB available, I recommend clearing off space on those drives. This can involve uninstalling applications you don’t use, deleting temporary or duplicate data, or otherwise removing files you don’t need.

As noted above, you can avoid the use of scratch disks altogether by making sure you have adequate system memory. So, if you’ve been looking for an excuse to upgrade your computer, this might be a good reason to do so.

Today’s Question: I have always used Lightroom Classic’s “import photos” feature to download the images from my camera. Why is it that the images are often imported out of sequence instead of in the order taken?

Tim’s Quick Answer: Images will generally be imported in what seems like a random order, based on the way data is written to and read from the media cards. You can ensure you’re browsing the images in the correct order by setting the sort order to Capture Time.

More Detail: You can change the sort order for your photos using the Sort popup that is available both in the Import dialog and on the toolbar below the grid view in the Library module in Lightroom Classic. In general I recommend using the Capture Time option so you’re seeing photos in the order they were taken.

When you import photos from a media card into Lightroom Classic, they won’t generally be downloaded in the same order they were captured due to how the data is written (and therefore read) from the media card. This can lead to some potential challenges in your workflow. For example, if you set the sort order to “Off” in the Import dialog and rename with a sequence number during import, sorting by filename versus capture time can result in a completely different sort order.

I recommend setting the sort order to Capture Time both in the import dialog and in the grid view in the Library module, unless you have a specific need to sort the images in a different order. This can be especially important if you’re renaming during import and will include a sequence number as part of the file renaming structure.