Ask Tim Grey

Today’s Question: Recently there have been articles and books about exposing raw captures far to the right in order to get better shadow details. Some authors suggest exposing so far to the right that the initial unprocessed raw file looks milky white with blown out highlights that are then brought back into proper exposure using the exposure slider in Adobe Camera Raw or Lightroom. Can you comment on this practice and what types of images might benefit from “extreme” exposure to the right then “recovery” in the raw converter?

Tim’s Quick Answer: The recommendation to “expose to the right” does have merit. By exposing an image as brightly as possible without losing detail in the brightest highlights, you are maximizing information and minimizing noise. There is a potential disadvantage to workflow efficiency, but you are also maximizing potential detail and image quality with this approach.

More Detail: While there is a potential benefit to exposing to the right, this approach shouldn’t be perceived as a cure for all potential issues related to image quality. My personal approach is to aim for an exposure where the right end of the histogram display reaches into the right-most section of the display (which is generally divided into four or five sections). But if I’m photographing a scene that has a very low dynamic range, I don’t apply an extreme exposure compensation because none of the tonal values will reach into the darkest range of the histogram in the first place.

Achieving the brightest exposure possible won’t have a dramatic impact on image quality under normal circumstances, where you have achieved a good exposure and you won’t need to brighten the shadow areas significantly. If you are already shooting at the minimum ISO setting for your camera, there is good light illuminating the scene, and you have established a good exposure that will require minimal adjustment after the capture, you can expect very good quality.

Therefore, when all is said and done, I treat the “expose to the right” concept as one that represents a good general habit to be in. I tend toward brighter exposures, but don’t stress about using this approach under all circumstances for every photo I capture.

Today’s Question: If a photographer opts to purchase a camera that is not equipped with a Low Pass Filter, is there a way to remove moire effects in Photoshop if they should appear in some images?

Tim’s Quick Answer: Yes, there are several options available when it comes to removing moiré patterns in Photoshop. The first approach would be to avoid them in the first place, of course, by adjusting focal length or other capture settings. But you can also reduce the appearance of moiré patterns using Adobe Camera Raw, the Camera Raw filter, or a simple blur applied selectively to the image.

More Detail: To begin with, you can generally avoid moiré patterns in the first place if you are aware of their potential. Simply by changing the focal length of the lens (if you are using a zoom lens), or changing the lens aperture, you can eliminate the interference patterns that cause moiré patterns. If you’re using a camera without a low pass filter you will obviously be aware of the potential risk, but you also need to evaluate the scene to determine whether there is fine texture that may lead to moiré patterns. Reviewing the images at a relatively high magnification on the camera’s LCD display will allow you to determine if the current camera settings are causing moiré patterns, and you can take steps to adjust your capture settings to avoid those patterns.

If you are processing a RAW capture that contains moiré patterns, you can use Adobe Camera Raw (or by extension, Lightroom’s Develop module) to reduce the appearance of these patterns. Simply select the Adjustment Brush, making sure that all of the adjustments are at their default values. Then increase the value for Moire Reduction to the maximum value of 100, and paint on the image in the area where the moiré patterns appear. You can then reduce the value for Moire Reduction to the minimum level required to remove the interference patterns.

The same adjustments referenced above can also be found in the Camera Raw filter if you are using Photoshop CC for a non-RAW capture (or a RAW capture that had already been processed). Simply choose Filter > Camera Raw Filter from the menu, and use the same controls referenced above.

If you are using an older version of Photoshop without the benefit of the Adjustment Brush in Adobe Camera Raw (or the Camera Raw Filter), you can also apply a selective blur to the image. For example, you can create a copy of the Background image layer by dragging the thumbnail for that layer to the Create New Layer button (the blank sheet of paper icon) at the bottom of the Layers panel. Then choose Filter > Blur > Gaussian Blur, and apply just as much blur as is needed to remove the appearance of the moiré patterns.

Next, add an inverted layer mask to the Background Copy layer you created by holding the Alt key on Windows or the Option key on Macintosh while clicking the Add Layer Mask button (the circle-inside-a-square icon) at the bottom of the Layers panel. This will add a layer mask that is filled with black, so the blurred version of the image will disappear. Then use the Brush tool with a soft-edged brush to paint with white into the areas where the moiré patterns appear, so that the blur effect only applies to those areas of the image.

Today’s Question: I add metadata to my photos in Adobe Bridge then import the photos into Lightroom and place them on the map [in the Map module, to add GPS location information to metadata for the photos]. Later I may go back and add more keywords in Bridge. When I bring up those particular photos in Lightroom, the icon comes up on the photo for  “Import Settings from Disk” which I do. But that causes the map icon to disappear on those photos and I have to place them on the map again. I wonder what is causing the map icon to disappear and whether those photos are really being removed from the Lightroom map?

Tim’s Quick Answer: The workflow you’re using is causing the metadata from Adobe Bridge to replace the metadata in Lightroom, causing you to lose all of the metadata that was only added in Lightroom. Put simply, I recommend only adding keywords or metadata from within Lightroom once you’ve imported photos into Lightroom.

More Detail: By default, Lightroom only stores metadata for your photos in the Lightroom catalog. Therefore, when you update metadata using Adobe Bridge for a photo that is already in the Lightroom catalog, there is a mismatch. Lightroom is only looking at the catalog, while Bridge is updating the XMP sidecar file for your RAW captures (or the actual image file in the case of other file types).

There are two possible solutions to avoid this mismatch situation, but I really only recommend the first option.

The first option is to avoid the mismatch altogether by using Lightroom as the exclusive tool for updating any metadata for your photos once those images have been imported into your Lightroom catalog. This is the approach I recommend, as it helps ensure you will avoid a wide variety of potential challenges related to the organization of your photos. Taking this a step further, I recommend that all work related to your photos should start within Lightroom. If you always treat Lightroom as the foundation of your workflow, you’ll avoid many of the challenges photographers run into, such as missing images, missing folders, metadata mismatches, and more.

The second approach is to have Lightroom automatically update the metadata for the files actually stored on the hard drive. With this approach the Lightroom catalog will still be updated to reflect all changes. However, in addition, Lightroom will write the updates to the XMP sidecar file for your RAW captures (or to the actual image file for other file types). This will not eliminate the metadata mismatch, but it will help ensure you don’t lose the GPS location information when you update your images in Lightroom based on what you changed in Bridge.

While I prefer to turn on the option to automatically update the XMP sidecar file for RAW captures (which can be found on the Metadata tab of the Catalog Settings dialog in Lightroom), I still very highly recommend that you only update metadata within Lightroom for images that are being managed by Lightroom.

So, stop updating metadata in Adobe Bridge after you’ve imported photos into Lightroom, and your workflow will function much more smoothly.

Today’s Question: You said “especially uncoated matte papers” [in a recent Ask Tim Grey eNewsletter on the topic of sharpening a photo for printing]. I thought all matte papers would be uncoated. Can you explain the differences?

Tim’s Quick Answer: Some matte papers do indeed include a special coating that provides a matte surface that takes on some of the behaviors of a glossy photo paper.

More Detail: While glossy papers have an obvious coating that enables the inks to “sit on top” of the paper, many matte papers also have a coating. The only difference is that the coating used on matte papers isn’t as “shiny”, so that the paper retains a matte appearance. The benefit of that coating can be tremendous in terms of the amount of saturation, detail, and even dynamic range you’re able to achieve with these matte papers.

The key challenge for an uncoated matte paper is that the inks get absorbed somewhat significantly by the paper. The result is a relatively dull appearance, with reduced contrast, reduced saturation, and lower dynamic range. By using special coatings with a mate paper surface, the inks will stay closer to the paper surface and will spread out less, helping achieve a result that is closer to what you would expect on a glossy (or semi-gloss paper) without the shiny appearance.

In some cases you may prefer the look of an uncoated matte paper, but I generally find that I prefer coated matte papers since they provide some of the benefits of a glossy surface while maintaining the aesthetic appeal of a matte paper.

Today’s Question: Does this technique make sense? “Placing a blank, white layer atop a .PSD can cut the file size in half?”

Tim’s Quick Answer: No, not really. This “trick” may have worked in older versions of Photoshop (or the person who tested it wasn’t being very methodical), but I’ve not been able to reproduce the effect in recent versions of Photoshop. But regardless, the real issue here (from what I can gather) is the “Maximize Compatibility” setting in Preferences, which when enabled will approximately double the base file size for PSD images.

More Detail: When I read about this technique, I immediately suspected the underlying issue related to the Maximize Compatibility option. Specifically, the white layer atop the stack of layers on the Layers panel would cause the preview for the image to be entirely white, which would result in a preview that compresses better and thus produces a smaller overall file size.

However, that approach would completely defeat the whole purpose of having the Maximize Compatibility feature turned on in the first place. The reason the Maximize Compatibility option causes the file size to double (compared to a flattened original image) is that this option causes a full-resolution composite preview of the image to be embedded. This allows other applications to see the actual appearance of the image without having to understand the various underlying layers that are specific to Photoshop.

However, rather than using this “trick”, you can simply turn off the Maximize Compatibility option in the first place. That way, rather than having a blank white preview you will have no preview at all, causing the file size to be approximately half of what it otherwise would have been with Maximize Compatibility turned on.

Keep in mind, however, that by turning off Maximize Compatibility for the PSD files you save, you won’t be able to see previews of those images with other applications that might otherwise be able to show a preview. You also won’t be able to import PSD files into Lightroom if Maximize Compatibility is turned off.

You can choose whether you want the Maximize Compatibility option enabled in the File Handling section of the Preferences dialog in Photoshop. I generally leave the option set to “Ask” so I can choose whether to enable Maximize Compatibility based on how I’ll be using the PSD file.

Today’s Question: What is the difference in effect on my image between making an adjustment in Camera Raw while in Bridge versus making the same adjustment with the Camera Raw filter after the image file is in Photoshop?  Is the adjustment better done in Bridge?

Tim’s Quick Answer: The basic effect applied to the images is the same whether you’re using Adobe Camera Raw to process an image or the Camera Raw filter in Photoshop. The key difference is that when processing a RAW capture in Adobe Camera Raw, you are taking advantage of the benefits of some of the adjustments being applied as part of the RAW conversion process. In other words, in both cases you are applying the same adjustments, but you are applying them to different data.

More Detail: As you may be aware, when you capture a RAW image the source file only contains one value for each pixel. In other words, for each pixel in the capture, only a red, green, or blue value is recorded (with some exceptions). The process of “filling in the gaps” is referred to as demosaicing, and there are benefits to including adjustments as part of this process in terms of retaining detail and improving quality.

Therefore, I highly recommend applying at least basic tonal and color adjustments during the conversion of the RAW capture, to ensure the best starting point for your image. In many respects I think it is reasonable to compare the RAW conversion process to the original capture. Just as you want to ensure the best initial capture, being careful to produce a good result from a RAW conversion can have a big impact on the final image.

The Camera Raw filter in Photoshop simply provides the same basic adjustments found in Adobe Camera Raw for images that have already been processed from a RAW capture to actual pixel values. You can therefore use the Camera Raw filter at any time while working on your photo to apply adjustments if you are more comfortable with the options available in Camera Raw compared to the other adjustment options found in Photoshop.

Today’s Question: Can you provide some guidance for the Smart Sharpen settings in Photoshop when preparing an image for printing?

Tim’s Quick Answer: The first thing I recommend when using the Smart Sharpen filter is to set the Remove option to “Lens Blur”. The Reduce Noise setting will depend, of course, on the degree of noise in the image, but generally a low setting can be used because you will have presumably applied noise reduction to the image already. Then, for high detail images set the Radius to a value somewhere around 1.0 pixels (generally a little lower, except for very large prints). For images with lower levels of detail and smoother transitions of that detail, use a higher setting for Radius, generally around 2.0 to 3.0 pixels. Then set the Amount to a value of around 150% or so (ranging between around 100% and 200%) for high detail images, and around 75% for lower detail images. The specific settings will, of course, vary a bit based on the print size and the degree of detail in the image.

More Detail: When printing, the key thing to keep in mind is that you’ll generally need to over-sharpen the image. For glossy paper you don’t need to over-sharpen too much, but for matte papers (especially uncoated matte papers) you may have to apply sharpening that seems slightly extreme in order to produce a good result in the print.

It can take a bit of practice to get accustomed to what an image should look like on your computer display to ensure a print with optimal sharpening. Practice can be very helpful in this regard.

For high-detail images you want the sharpening effect to be applied to relatively small areas in relation to the size of the transitions among detail in the image. For lower-detail images you need to compensate by using a higher setting for Radius, so the sharpening effect will spread out a bit more.

When using a relatively low setting for Radius, you need to use a relatively high setting for Amount. And when you are using a relatively high setting for Radius you need to use a relatively low setting for Amount.

It is worth noting that you can also mitigate the sharpening effect in the dark shadow or bright highlight areas of a photo by expending the Shadows/Highlights section. This will provide independent controls for the Shadows and Highlights. You can then use the Fade Amount slider to reduce the application of sharpening in the shadows or highlights. You can also expand the range of tonal values being affected by this mitigation using the Tonal Width slider. Finally, you can use the Radius setting for Shadows and Highlights to determine how large an area around each pixel will be evaluated for purposes of determining whether that area represents a highlight or shadow area.

Today’s Question: A friend recently told me he was using Lightroom 5 with smart previews and Dropbox to synchronize his Lightroom catalogue. That is, he put his catalogue in Dropbox, set up smart previews in Lightroom and was able to work on his laptop and have it all synced to his main computer where all the original images were stored. I think i understand the concept but was curious about your take on the subject.

Tim’s Quick Answer: This absolutely works, but it does make me a little nervous. In concept, provided you have an adequately fast Internet connection (or aren’t generally in a tremendous hurry), you can synchronize your Lightroom catalog via Dropbox (or a similar service) and access your Lightroom catalog across multiple computers. In fairness, I’ve never experienced any problems when synchronizing a Lightroom catalog via Dropbox, and I’ve never heard of photographers having any serious problems. But it does make me nervous to take this approach.

Tim’s Quick Answer: This absolutely works, but it does make me a little nervous. In concept, provided you have an adequately fast Internet connection (or aren’t generally in a tremendous hurry), you can synchronize your Lightroom catalog via Dropbox (or a similar service) and access your Lightroom catalog across multiple computers. In fairness, I’ve never experienced any problems when synchronizing a Lightroom catalog via Dropbox, and I’ve never heard of photographers having any serious problems. But it does make me nervous to take this approach.

More Detail: When you access a Lightroom catalog (or other files) “remotely” using Dropbox (or a similar service), you aren’t actually working directly with the files on an Internet-connected server. What’s actually happening is that you are accessing the files locally on your computer, but those files are being synchronized via Dropbox.

So, for example, you could place your Lightroom catalog files in your Dropbox folder, and then access those files via several different computers. But when you do so, the files are actually copied to each of those computers. So you’re actually accessing the files locally, but they are being synchronized across multiple computers via Dropbox.

The biggest challenge here is that the files related to your Lightroom catalog can get rather large, especially the preview files. This can cause the synchronization to be rather slow, depending on the speed of your Internet connection. The key thing to remember here is that if you have updated your Lightroom catalog on one computer, you can’t make updates on another computer until the synchronization is completed. In theory the service (such as Dropbox) that is performing the synchronization won’t let you update a file (such as your Lightroom catalog) until the synchronization for that file is complete. But trusting this limitation makes me nervous, and waiting for the synchronization to complete could involve considerable time with a large set of catalog files on a slow Internet connection.

So, again, this is perfectly feasible, but potentially problematic. I’ve performed considerable testing using Dropbox to synchronize a Lightroom catalog across multiple computers without any difficulty, but I don’t feel comfortable enough with this solution (especially considering potential latency based on the Internet connection) that I’m willing to use this approach with my “real” Lightroom catalog.

Today’s Question: Upon reviewing a group of recently imported images into Lightroom 5, I noticed strong alternating blue and yellow bands across textured metal surfaces in 3 of my photos. Lightroom automatically removed the banding in 2 of the images within a few seconds of switching to the Develop Module. However, the third and most strongly banded image, containing a bank of escalator steps, remains unaffected. Any suggestions?

Tim’s Quick Answer: Your description certainly sounds like chromatic aberration. Presumably you have the “Remove Chromatic Aberration” checkbox turned on with your default settings in the Lens Corrections section of the right panel in Lightroom’s Develop module. However, this option doesn’t always provide a complete solution. You can, however, make use of the Defringe options below the “Remove Chromatic Aberration” checkbox on the Color tab of the Lens Corrections section to further improve the result.

More Detail: The type of visible artifacts you describe can be caused by a variety of factors, and fortunately can be resolved very effectively with the Lens Corrections adjustments available in Lightroom’s Develop module as well as Adobe Camera Raw, among a variety of other software tools that provide this correction option.

I find that in about half of the images that require a correction for this type of color fringing, the “Remove Chromatic Aberration” checkbox provides a good solution. In the other half of images that require this correction the Defringe controls provide enough control to resolve the color fringing.

There are two sets of controls for Defringe, allowing you to adjust the Amount (strength) of the correction and the range of color values to be corrected. The first set of sliders applies to magenta fringing in the image, and the second set applies to green fringing.

My approach for the Defringe sliders starts by zooming in on the area of the image where the color fringing is visible. Then increase the Amount slider significantly for the color correction that is needed (or the color that is closest to the problem color) to see if the fringing is corrected. If the color fringing is not completely removed with a large increase in the Amount control, you can expand the color range for the applicable Hue slider. Be careful not to increase the range too much, because doing so may cause the correction to blend into areas where you don’t want the color removed.

You can then reduce the value for the applicable Amount slider to a more appropriate level. By fine-tuning the specific range of colors being impacted and the strength of the adjustment for each color, you can generally produce a great result. In some cases there may be a minor amount of fringing left behind, but generally with a bit of careful attention to the slider values you can achieve a very good (and often excellent) improvement for the photo.

Today’s Question: Canon has introduced a new 5DS R, a camera without a high pass filter over the sensor. This is supposed to make the image sharper. In Photoshop we use the high pass filter to increase sharpness. Please explain.

Tim’s Quick Answer: The short answer here is that the High Pass filter (in Photoshop for example) doesn’t truly sharpen a photo. Rather, it removes low detail areas of an image and retains high detail areas, creating contrast in the process. That contrast can then be used to sharpen with the help of a blend mode. A high pass filter on a camera’s image sensor filters out some of the low frequency information to avoid artifacts, but softens the image in the process of filtering out some of the information projected by the lens.

More Detail: In other words, both filters are doing approximately the same thing, but they are generally used in different ways. A high pass filter will filter out low frequency information and retain high frequency information. This is helpful in image sensors for preventing moire patterns and other visible artifacts in a photo. However, because some information is being filtered out, there is a degree of softness imparted to the image. In other words, there is a tradeoff here, but many photographers would choose a higher degree of sharpness and detail over the potential for removing certain artifacts in the image.

The High Pass filter in Photoshop also filters out low frequency (low detail) information in a photo, preserving (and enhancing) the high frequency (high detail) areas. The result is something of an embossed effect. When combined with one of the “contrast” blend modes (such as Overlay), this can create a sharpening effect. The light areas of the embossed copy of the photo will brighten one side of a contrast edge, and the dark areas of the embossed copy will darken the other side, resulting in the appearance of greater detail and sharpness.

So, in both cases the same basic filtering of information is being used for different purposes, but with variations on how those filters are implemented contributing to the difference.