Month: August 2023

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.

Today’s Question: As a follow-up to the “Defining Your Workflow” presentations, I wonder about the culling software that are out there. I would be interested in your opinion as to whether or not you think they are worthwhile and worth the cost. If so, is there one you might prefer?

Tim’s Quick Answer: While there are some good and interesting tools for culling software automatically, I find that these are most useful for portrait photographers and can create a more cumbersome workflow for other types of photographers, especially in the context of a workflow that revolves around Lightroom Classic. One good option you might look at is Aftershoot (https://aftershoot.com).

More Detail: The idea of automatic culling software for photos is pretty straightforward. The software analyzes your images, and helps to identify those you might be most interested in reviewing and those that may be outtakes. This can be helpful when it works well, but in my view the software is really only helpful if you can trust the results without having to review all the images to confirm those results are accurate.

My experience has been that while software such as Aftershoot can certainly mark photos based on attributes such as being out of focus or featuring a person with their eyes closed, the result does not necessarily replace a manual visual evaluation of your photos.

For portrait photographers who capture a large number of photos of people, I would say this type of software is definitely worth evaluating, as it can most certainly help you more quickly focus on the photos that are most likely to represent your favorites. For other types of photographers, such as landscape and travel photographers, I would say the software provides less meaningful utility.

My main issue with using culling software beyond Lightroom Classic is that it can create a more cumbersome workflow that doesn’t necessarily save considerable time when compared to a manual review within Lightroom Classic. That’s especially true considering that even after using culling software you’re almost certainly going to want to review the photos yourself.

In other words, the culling software can help you focus on the photos that are most likely to become favorites, but a manual review is still necessary in my view. I would use the analogy of spam filtering for email. In many cases the spam filter does a good job of identifying the most obvious spam, but many non-spam messages still end up in the spam folder, and some spam messages still slip through.

Having said all that, if you think culling software might aid your workflow, I recommend taking a look at Aftershoot. You can find more information and download a free trial here:

https://aftershoot.com

Today’s Question: Is there a way to copy white balance from one image to another in Lightroom Classic? I am shooting a lot of infrared, and the custom white balance is usually under 2000 Kelvin, which is the low limit for Lightroom Classic. Occasionally I forget to white balance in camera. Is there a way to copy the custom white balance from an earlier grey card for that frequency of infrared to another photo in Lightroom Classic? Could I create a custom profile to do this?

Tim’s Quick Answer: You can copy the white balance settings from one image to another in Lightroom Classic. In situations where you need a stronger adjustment for color, you can use a custom Tone Curve adjustment for individual color channels. These adjustments could be saved as a preset if they represent common settings needed for multiple images.

More Detail: In Lightroom Classic you can copy settings from one image to another in a variety of ways. One quick option is to copy the settings from one image and paste them to another. For example, you can select the image that has a good white balance adjustment applied and click the Copy button at the bottom of the left panel in the Develop module.

In the dialog that appears you can enable only the adjustments you want to apply to the other image. For example, in this case you may want to click the “Check None” button so that none of the adjustments are enabled. Then turn on the checkbox for White Balance, along with any other adjustments you want to copy from the source image. Click the Copy button at the bottom-right of the dialog to copy the selected settings.

Next, select the image you want to apply the adjustments to and click the Paste button at the bottom of the left panel. This will apply the adjustments you copied from the other image to the current image, which in this context will apply the same color temperature compensation.

If you’re finding that the adjustments aren’t strong enough for extreme situations, such as with infrared capture or scenes illuminated by very strongly colored light, you can supplement the White Balance adjustment with a Tone Curve adjustment focused on specific channels.

For example, in the Tone Curve adjustment section on the right panel in the Develop module you can select the blue channel from the Adjust control above the curve. Then click at the center of the curve for the blue channel and drag downward if you want to shift toward a more yellow (warm) appearance or drag upward if you want to shift toward a more blue (cool) appearance.

If you’ve applied these adjustments to an image and want to create a preset to use for other images captured under similar conditions, you can click the plus button to the right of the Presets heading on the left panel and choose “Create Preset” from the popup menu. In the dialog that appears enter a meaningful name for the preset in the Preset Name field and turn on the checkboxes for the adjustments you want to copy. Click the Create button at the bottom-right of the dialog and that preset can then be applied to other images that require the same adjustment settings.