Category: Ask Tim Grey

Today’s Question: Regarding your answer about the various dates and times for photos, is it possible to update the capture time for photos in Adobe Bridge, such as when I forget to update the time zone on my camera?

Tim’s Quick Answer: You can update the capture time for a batch of photos in Adobe Bridge by selecting the photos and choosing Edit > Edit Capture Time from the menu. It is also possible to update the capture time for a single photo using the “Date Time Original” field in the Camera Data section of metadata.

More Detail: If you neglect to update the time zone on your camera the capture time in metadata for the photos captured with the wrong setting will obviously be off by a particular number of hours. It is very easy to update the capture time in this scenario using Adobe Bridge.

The first step is to select the photos you need to update the capture time for. Then from the menu choose Edit > Edit Capture Time. Under the “Type of Adjustment” heading in the Edit Capture Time dialog, select “Shift by hours, minutes and seconds”. Then select Add if you need to adjust to a later time, or Subtract if you need to shift to an earlier time. You can then enter values for the Hours and Minutes fields as applicable. In most cases this will only require that you enter the number for Hours, but there are time zones in some areas that are off by thirty minutes compared to the neighboring time zone.

Once you’ve configured the settings for the capture time correction for the selected photos, click the Change button. This will update the values for Date Created and Date Time Original in metadata for the selected photos.

Note that you can also directly edit the capture date and time for an individual photo with the “Date Time Original” field in the Camera Data section of the Metadata tab in Adobe Bridge. This field is fully editable, so you can simply click in the field and make any changes you’d like. You can also click the calendar icon to the right of the field to bring up the Edit Capture Time dialog outlined above, so you can use that dialog rather than a direct editing of the metadata field.

Today’s Question: I’m finding that a small percentage of my photos end up with the date they were moved as their ‘created’ date. I know the image date is incorrect, in some cases by as much as ten years. I know how to input the correct date but how do I stop or prevent that change from happening in the first place?

Tim’s Quick Answer: You should always see the correct capture time in the “Date Time Original” field in Lightroom Classic or Adobe Bridge. The “Date Time” field in Lightroom Classic or the Date File Modified” field in Adobe Bridge will show the date and time the file was moved, such as when moving to a different hard drive.

More Detail: There are several dates shown in metadata in Lightroom Classic and Adobe Bridge, which can certainly lead to confusion when those dates don’t match for a given photo.

The “Date Time Original” field in Lightroom Classic and Adobe Bridge will show you the data the photo was captured, which of course may not match the original value for the date and time of capture if you adjusted the capture time after the fact. This might be the case if you had neglected to update the time zone on your camera, for example, and changed the date of capture for your photos later.

The “Date Time Digitized” field in Lightroom Classic or the “Date Created” field in Adobe Bridge would also match the original time reflected in metadata in the camera at the time the photo was captured. Therefore, this date information can also be depended upon to reflect the original capture time, though without taking into account changes to the capture time applied later in your workflow.

The “Date Time” field in Lightroom Classic or the “Date File Modified” field in Adobe Bridge will reflect the date the file was created in the current hard drive location, which could be a much more recent date than the date of capture if the file had been moved to a different drive. For example, when I copy selections of photos to a different hard drive to use with a demo catalog in Lightroom Classic, the “Date Time” field shows when I copied the files rather than when the photos were captured.

In Lightroom Classic you’ll also find the “Metadata Date” field, which is a reflection of when the metadata was most recently updated. This field might obviously be updated quite often, such as when you assign a star rating or add keywords to the photo, for example.

My recommendation is to refer to the “Date Time Original” field when you want to confirm the date and time of capture, and to generally ignore the other date fields in metadata to avoid confusion, unless you specifically need to review the additional information contained in those other fields.

Today’s Question: I have an old Windows PC with a copy of Lightroom Classic on it. I don’t use that computer anymore as I have a new PC with my second copy of Lightroom Classic on it. How should I remove my first copy of Lightroom Classic from my old PC before getting rid of it? I want to be able to retain the rights to have two copies of Lightroom Classic installed.

Tim’s Quick Answer: All you need to do is sign out of the Creative Cloud application on your old computer, so that you’ll then be able to sign in using another computer.

More Detail: The applications included with an Adobe Creative Cloud subscription plan are limited to having two active copies at a time. Therefore, if you’re using Lightroom Classic on two computers, you won’t be able to activate the software on a third computer unless you sign out of your account on one of the other computers.

Fortunately, simply signing out of the Creative Cloud application (which is the same application where you install updates to Creative Cloud applications) will deactivate the applications on that computer. That in turn will make it possible to then sign in on another computer, with a total of two active computers at any time signed in for your Creative Cloud subscription.

To sign out of Creative Cloud on one of your computers, start by bringing up the Creative Cloud application. You can launch the application directly like any other installed application, but you should also see an icon for Creative Cloud on the taskbar on Windows or the dock on Macintosh. Click that icon to bring up the Creative Cloud application. Then, at the top-right corner of the Creative Cloud window click on the icon representing your user account and choose “Sign out” from the popup menu.

Today’s Question: I have for several years used a 200 GB external SSD for my Lightroom Classic catalog and a 2 TB regular external drive for my photos. My total used space for those is about 900 GB. Since a 2 TB SSD is now pretty reasonably priced, is there any advantage in having separate drives for the catalog and the pics or will one new 2 TB SSD work as well or better?

Tim’s Quick Answer: If you’re going to store the Lightroom Classic catalog on an external drive there’s no need to keep the catalog on a separate hard drive from the photos. In general, with this approach I recommend keeping both on the same drive for convenience in terms of backing up and easily having access to both the catalog and photos without having to connect two drives.

More Detail: If performance is your priority, then it is generally best to keep the Lightroom Classic catalog on an internal hard drive. You can still keep the photos on an external hard drive if you prefer, such as if you don’t have adequate internal storage. However, if you’re going to keep the catalog on an external hard drive, I recommend keeping the catalog and photos on the same drive.

Having the catalog and photos on the same drive means you’ll always have access to your photos whenever you have access to your catalog. That is convenient, and also makes it easier to maintain a backup of both the catalog and photos with a single overall workflow.

So, in general I would say it is best to keep the catalog on an internal hard drive for performance reasons. But if you want to keep the catalog on an external drive, such as to enable you to move the catalog between computers, I recommend keeping the catalog on the same drive as the photos.

Today’s Question: I often apply many adjustment layers to an image, and I am wondering if that diminishes image quality. For example, I might increase contrast using Curves or Levels and then if I later decide I want more contrast, rather than tweaking the first contrast layer, I often add a second Curves or Levels layer to get the additional contrast. That way if I don’t like the additional contrast, rather than trying to get back to what I had originally, I can just delete the second layer I used to add more contrast. But is doing it this way a bad idea?

Tim’s Quick Answer: There is a minor risk of image degradation with this approach, but that risk isn’t so high that I would encourage you to avoid adding a duplicative adjustment layer.

More Detail: As noted in yesterday’s answer, using an adjustment layer rather than multiple direct adjustments to a pixel layer can help maintain greater image quality because you aren’t compounding the loss of detail from multiple adjustments. Each adjustment layer counts as only a single adjustment, no matter how many times you’ve refined the settings for the adjustment layer.

If you add more than one adjustment layer of the same type, of course, that counts as more than one adjustment. This creates the risk of a minor degradation in image quality, but as long as the adjustments aren’t extreme this would really be a very minor issue.

While I consider it a best practice to use only a single adjustment layer of a given type, there are reasons you may prefer to use more than one layer of the same type. As noted in today’s question, adding another adjustment layer rather than modifying an existing layer provides the flexibility of more easily returning to previous settings if you decide the additional adjustment layer isn’t providing the benefit you were looking for.

In addition, you may want to add multiple adjustment layers of the same type if you are applying targeted adjustments with a layer mask. You might have a Curves adjustment layer that is applying a global adjustment to the image, for example, and then add another Curves adjustment layer that is masked to only affect the sky. You might even add a third Curves adjustment layer with a mask to adjust only the foreground in the image.

So, while I consider it best to only use a single adjustment layer of a given type, there are certainly other considerations that may cause you to want to have duplicate adjustment layers. The risk of image degradation from this approach is quite modest as long as the adjustments aren’t extreme, so I wouldn’t give up other benefits just to avoid having duplicate adjustment layers.

Today’s Question: You said that you retain all layers for images you work in in Photoshop in part to maximize image quality. How does using layers improve image quality?

Tim’s Quick Answer: Using layers in Photoshop primarily provides for a more flexible workflow. However, using adjustment layers rather than adjusting pixel layers directly can also benefit image quality by virtue of not compounding the effect of multiple adjustments.

More Detail: When you apply an adjustment to an image you are obviously altering the pixel values. Each time you apply an additional adjustment you’re compounding the effect, and this can have a negative impact on image detail and overall quality.

For example, increasing contrast can cause a loss of some detail in the dark shadows and bright highlights. That loss is generally very modest, and the improved appearance from the enhanced contrast is likely worth the very slight loss of detail.

However, if you enhance contrast in multiple steps rather than a single step, there can be a more significant loss of detail than if you achieved the same result with a single adjustment. For example, if you gradually increase contrast in ten steps that can cause more degradation than if you achieved the same degree of increased contrast in one step.

When using an adjustment layer in Photoshop, that adjustment layer provides the same effect as if you had only applied one adjustment, no matter how many times you fine-tune the settings for the adjustment layer. Therefore, when using an adjustment layer there is no compounding effect cause by altering the same adjustment multiple times.

To be sure, with normal adjustments for a photo the benefit in terms of image quality when it comes to using adjustment layers is very modest. However, I strongly recommend using layers when optimizing photos to take advantage of the greater flexibility and the potential benefit in terms of image quality, minor though it may be.

Today’s Question: As a follow-up question, do you flatten the image before saving it as a TIFF, or maintain the layers in case you need to make any adjustments as you refine the printing processing?

Tim’s Quick Answer: While I would save a flattened copy of the source image when sending a file for printing, I always retain the “original” version of the image with all layers intact so I can refine the image later if needed.

More Detail: When I process an image in Photoshop, I often make extensive use of layers, including adjustment layers, additional image layers for cleaning blemishes, layer masks with adjustment layers for targeted adjustments, and more. My preference is to preserve all layers for that image so I can always go back and make changes later if needed.

My original capture, of course, is generally a raw capture. I typically adjust that image in Lightroom Classic, which in many cases might be all the editing I need for a photo. However, some images require a little more work, which means sending the image to Photoshop.

I prefer a layer-based workflow in Photoshop to help maximize image quality and give me more flexibility in my workflow. I save this image as either a Photoshop PSD file or a TIFF image, with all layers intact. I can then open the image in Photoshop at a later time so I can refine those layers as needed.

When sending an image to someone else, such as for printing, they generally don’t need to have access to the layers, and I generally don’t want them to have access to the layers I used to create the final version of the image. Therefore, when preparing an image such as for printing, I will save the result as a new file with all layers flattened.

Today’s Question: In the [August 3rd] newsletter you discuss converting a TIFF file to a JPEG file and the resulting file size. At the end you say, “JPEG images should only be used for derivative images that are shared digitally, not as archival images or as the basis of photo prints.” What file format do you recommend for photo printing, especially if sending the file to a third-party printer?

Tim’s Quick Answer: I recommend using the TIFF file format for saving photos that have been prepared for printing, as long as that is supported by the print service you’ll use.

More Detail: Most photographers are (I hope!) capturing their photos in a raw capture format. That is great for maximizing image quality and for optimizing the photo, but you wouldn’t want to send a raw capture format to a print service. Whenever you will share a photo with someone else for any purpose, you would want to create a derivative copy of the original capture.

As mentioned in my answer from August 3rd, for sharing online or other digital sharing the JPEG format is a good option because it provides a smaller file size. There is some degradation in image quality caused by the JPEG compression however, so I don’t recommend using the JPEG file format for images that will be printed.

In my view the best file format to use for printing is the TIFF format, either without compression or with lossless compression such as LZW or ZIP. This will ensure optimal image quality for the derivative created from your source capture, which in turn will help ensure the best print quality.

Of course, when sending a file to a third-party printer it is also important to meet the requirements of that provider. With some online printing services, for example, you may be limited to only being able to upload JPEG and possibly PNG images. This isn’t ideal, but in general you can still achieve good print quality even with a JPEG file as long as a high setting for quality was used.

If possible, however, I recommend saving photos intended for printing with a file format that will not involve any lossy compression. The TIFF file format meets this requirement, while also being widely supported by most printing services.

Today’s Question: Should you do noise reduction before you start editing an image or after?

Tim’s Quick Answer: I recommend applying noise reduction early in your workflow for optimizing a photo, though depending on which software you’re using that timing may not be as important.

More Detail: Various adjustments can amplify the appearance of noise in an image or make the noise more problematic. For example, sharpening involves an enhancement of edge contrast, and this can cause the noise to be exaggerated to some extent. Because of these issues I recommend applying noise reduction as early in your workflow as possible.

However, the software you’re using may make this timing less critical. For example, if you’re using Lightroom Classic to optimize your photos, the normal noise reduction that can be applied manually can be used in any order. It doesn’t matter whether you apply this noise reduction before sharpening or after, for example, because the adjustments aren’t applied directly to the image. Rather, the adjustments effective represent metadata values, and they aren’t applied until you create output from the source image, such as when exporting a derivative copy.

In situations where the noise reduction is being applied to the image before other adjustments, I do recommend applying noise reduction as one of the first adjustments to an image.

For example, if you’re going to use the AI Denoise feature in Lightroom Classic (or Camera Raw) that should be the first step you apply. After that noise reduction is applied to the image you can continue with any other adjustments in any order you prefer.

Whenever noise reduction is actually altering pixel values in an image, I recommend applying that noise reduction first (or as early as possible). In situations where the adjustments aren’t altering the pixels directly, such as with most adjustments in the Develop module in Lightroom Classic, the various adjustments can be applied in any order you’d like.

Today’s Question: I have negative scan which is a fairly reasonable size TIF file (6 MB). However, when I export as a JPEG, the file size is tiny (300 KB). What am I doing wrong? I tried 300 pixels per inch and 2400 pixels per inch, but these resolutions had no effect on the JPEG file size.

Tim’s Quick Answer: You’re not doing anything wrong. The smaller file size is simply a matter of the compression being applied to the JPEG copy of the image.

More Detail: In most applications, saving an image as a JPEG file automatically means that lossy compression is applied. This means that the file size will be reduced by simplifying the description of the pixel contents of the image, resulting in some degree of loss of fidelity and image quality. In other words, if you save the exact same image with the same pixel dimensions as both a TIFF and JPEG image, the JPEG will always have a smaller file size. In most cases the difference in file size will be quite significant.

As a general rule, a TIFF file with a bit depth of 8-bits per channel will have a file size that is about three times the number of megapixels in the image. So, for example, a 20-megapixel image saved as an 8-bit per channel TIFF image would result in a file size of about 60 megabytes. If that same image is saved as a 16-bit per channel image the file size would double to about 120MB.

A JPEG file saved from the same 20-megapixel image would have a file size in the general vicinity of 10MB, though the actual results can vary significantly.

There are three key factors that affect the file size for a JPEG image. The overall pixel dimensions are obviously a significant factor. The JPEG quality setting is also significant, as it determines the strength of the compression being applied. A higher quality setting obviously helps maintain better image quality, but results in a larger file size. A lower quality setting will result in a smaller file size, but image quality can be degraded somewhat significantly in the process.

The third factor is the relative complexity of the image. The simpler the image is, the more it can be compressed without degrading image quality. For example, a blank white image saved as a JPEG will have a significantly smaller file size than that of a normal photographic image. If the 10MB JPEG image referenced above were filled with white and saved as a new JPEG, that file size would be about 1MB.

So, JPEG files will always be smaller than most other file formats because of the compression applied to those JPEG images. Of course, quality can be degraded as part of the process of compressing the data, which is why JPEG images should only be used for derivative images that are shared digitally, not as archival images or as the basis of photo prints.

Note, by the way, that the pixel per inch (PPI) resolution won’t have any impact on the file size. That is just a metadata value that affects the output size when printing but doesn’t affect the file size because it doesn’t affect the overall pixel dimensions of the image.