Pixels versus Photosites

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Today’s Question: It is my understanding that pixels are not the same as photosites where each photosite records one color [on a digital camera sensor]. The digital to analog converter creates pixels. What’s the real story?

Tim’s Quick Answer: This is mostly a matter of semantics. While the term photosite refers to a physical component of an image sensor, it is extremely common to refer to photosites as pixels even though pixels are elements of a digital image.

More Detail: The term pixel was derived from “picture element” and is used to describe the smallest element of a raster-based image (as opposed to a vector-based image). A pixel is therefore a component of a digital image, and a digital image often contains many (often millions) of pixels.

Technically speaking the individual elements on an image sensor are photosites, not pixels. Those photosites contain hardware that converts light energy into a discreet digital value that then gets processed into the values that define pixels in the resulting digital image.

It is also true that digital cameras only record a single color for each photosite, because those photosites aren’t actually recording color but rather light intensity based on light that has been filtered for color. Even sensors that capture full color for each pixel, such as the Foveon X3 sensor, only capture one color per photosite. In the case of the Foveon sensor there are simply three photosites on the image sensor corresponding to each pixel in the final image.

In common usage, the photosites on an image sensor are often referred to as pixels. For example, most digital camera marketing materials describe resolution in megapixels (millions of pixels) since the images captured with that sensor will contain the number of pixels referenced. But we tend to think of the image sensor as having a particular number of megapixels, which contributes to the photosites being referred to as pixels.

In my earlier days I was more pedantic about this issue, and would use the term “photosite” when referring to an image sensor and “pixel” to refer to a digital image. I’ve since decided to conform with the more common use of the term pixel when talking about photosites. I similarly stopped using all capital letters when talking about raw captures, since raw in this context is not an acronym, even though I liked using all caps for raw so that it stood out like the other acronyms and initialisms used for other file formats. And yes, I do differentiate between acronyms and initialisms, even though I no longer tend to differentiate in the same way between photosites and pixels.

By the way, I also find it amusing that photosite is the technical name for what amounts to a pixel on an image sensor, but my spell checker doesn’t think photosite is really a word.

Process Version Workflow

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Today’s Question: Is it a reasonable workflow alternative with an image previously processed in an older Lightroom Development version to export a duplicate, remove all processing and reprocess with the new Develop module?

Tim’s Quick Answer: I would suggest simply creating a virtual copy rather than creating a duplicate of the original image file. You can then use updated settings for either the original image or the virtual copy, preserving the original look based on the older process version.

More Detail: Today’s question is a follow-up from a couple of questions about process versions in Lightroom Classic that I addressed recently. A process version basically represents a particular version of Lightroom Classic in the context of the Develop module. To take advantage of all the latest features and adjustment updates, you need to be working with the latest process version, which can be viewed and changed in the Calibration section of the right panel in the Develop module..

However, if you change the process version for a photo it is possible (or even likely) that the appearance of the photo may change. It can therefore be a good idea to preserve the appearance based on the existing process version before updating to a new process version.

As suggested in today’s question, you could certainly create a duplicate copy of the original image, such as by exporting a copy and adding that copy to the Lightroom Classic catalog. However, you can also easily accomplish this by using a virtual copy.

For example, you could right-click on an image that is set to an older process version and choose “Create Virtual Copy” from the popup menu. You could then update the process version for just one of those images. In this case I would probably keep the old process version set for the virtual copy, and update the process version for the original image.

You could then update the adjustment settings for the image you updated the virtual copy for, even going so far as to click the Reset button at the bottom of the right panel in the Develop module to reset all adjustments to their defaults. But the point is that you can refine the overall adjustments based on the latest process version, while preserving the previous version of the image with an older process version for your reference.

Raw Captures with Full Color

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Today’s Question: In your answer about TIFF versus raw captures you said that “most raw captures don’t contain full color information for each pixel”. Wouldn’t this be true of all raw captures since that’s what makes a raw capture “raw”?

Tim’s Quick Answer: While most digital camera image sensors only capture a single color for each pixel, not all sensors have this limit. For example, the Foveon X3 sensor captures full color for each pixel.

More Detail: Most camera image sensors use a Bayer pattern array, where out of every four pixels two record green light, one records red light, and one records blue light. Other image sensors use a variation on this concept. But most only record one color value (red, green, or blue) for each pixel. Software then processes this information to calculate the “missing” color values for each pixel to generate the full-color image.

This issue is generally referred to as the image being mosaiced, meaning it contains a mosaic of different values that don’t represent complete image data. This mosaiced attribute is what we generally consider to represent a raw capture.

However, there is at least one exception that has made it into production cameras. That exception is the Foveon X3 sensor, which uses a layered approach to record full color information for all pixels on the sensor.

While the technology and concept of the Foveon X3 sensor is impressive, that hasn’t translated into wide adoption. The company that created the Foveon sensor was acquired by Sigma a number of years ago, and the sensor has only been available in Sigma cameras. The Sigma cameras haven’t seen wide adoption.

So, the vast majority of cameras don’t capture full color information for all pixels, but there are exceptions.

File Size versus Print Size

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Today’s Question: If a TIFF file is much larger [compared to a raw capture], does that mean you can also print much larger without any loss of resolution?

Tim’s Quick Answer: No, because the file size of a TIFF is not due to greater resolution, but rather due to the nature of the file.

More Detail: Today’s question was a follow-up to a prior question about the large size of a TIFF file created by sending a raw capture to Photoshop from Lightroom Classic. As I explained in my answer to that question, a TIFF file created from a raw capture will generally be about three times larger than the original capture.

While an image with greater resolution will have a larger file size, that doesn’t mean that a larger file size automatically means there is greater resolution in the image. In other words, just because an image has a larger file size doesn’t always mean it can be printed at a larger size with equal quality compared to an image with a smaller file size.

In the case of a raw capture compared to a TIFF file, the reason the raw capture generally has a file size that is one-third the size of the TIFF image is that most raw captures don’t contain full color information for each pixel. Rather, in most cases each pixel will only have a value for either red, green, or blue, not all three. Because a TIFF file would have all three color values for every pixel, the file will be about three times the size.

Similarly, if you had added additional image layers to an image in Photoshop, such as when creating a composite image, the file size would be larger but the image couldn’t be printed any larger without degrading quality.

Another example going in the other direction would involve saving an image as a JPEG file. Even though the file size would be significantly smaller, the image could still be printed at about the same size as the source image, with the caveat that the print quality would be degraded at least slightly based on the JPEG compression.

Ultimately what determines how large an image can be printed with good quality is the resolution of the image, meaning the total number of pixels in the image. While a raw capture generally doesn’t contain full color information for each pixel, it can still be thought of as having the full resolution represented by the image sensor. The raw capture just needs to be processed to generate the full color information for all pixels.

Unwanted Icon on Layer Mask

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Today’s Question: Enlarging the thumbnails on the Layers panel in Photoshop made it easier to see the layers and layer masks, but there is still a small intrusive thumbnail appearing on the mask. I was hoping to get rid of the layer mask icon altogether, but I guess this isn’t an option?

Tim’s Quick Answer: The new badge that appears at the bottom-right corner of layer masks in Photoshop is a new feature of Photoshop version 25.1. The public beta version of Photoshop includes an option to remove the badges.

More Detail: Today’s question is a follow-up to Monday’s question, where I addressed the option to enlarge the thumbnails for layers and layer masks on the Layers panel in Photoshop. However, with the latest update to version 25.1 of Photoshop there is a new badge feature that puts an icon on the layer mask for any layers that include a mask.

Several readers have reached out to me about this, as they find the badge gets in the way of evaluating a layer mask. I completely agree that the new badge icon isn’t all that helpful and can interfere with evaluating layer masks.

In Photoshop version 25.1 there isn’t an option to remove the badges on layer masks. However, there is such an option in the current public beta version of Photoshop. So, if you want to get rid of the badge icons you could either revert to an earlier version of Photoshop or use the public beta while we await an update to Photoshop that will include the option to remove the badge.

If you install the public beta version of Photoshop (via the “Beta apps” category on the Apps tab of the Creative Cloud application), you can click on the panel popup menu button at the top-right of the Layers panel and choose “Panel Options” to bring up the Layers Panel Options dialog. There you’ll find a “Show layer mask badges” checkbox that you can turn off to remove the badges on layer masks.

I would assume that this option in the public beta will soon be available in an update to the production version of Photoshop soon. At least I hope so, because I certainly don’t think the badges on layer masks provide a benefit, and I suggest disabling them.

Deleting Photos in Book Module

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Today’s Question: I am working on a book in the Book module in Lightroom Classic and when I try to delete a photo from the book page it only removes it from that page and puts it into the filmstrip. When I go to the filmstrip to delete it the popup is grayed out. If I go to the Library Module, I am able to delete any photo as in the past. Any suggestions for this issue would be welcomed.

Tim’s Quick Answer: The Book module in Lightroom Classic is the only module where you’re not able to delete a photo. You can remove a photo from the page layout, remove a photo from a collection if you’re working with a collection, but not delete a photo if you’re working with a folder.

More Detail: In general, you can delete a photo in Lightroom Classic by right-clicking on the photo and choosing “Remove Photo” from the popup menu. However, this command is only available when browsing a folder rather than a collection, and it isn’t available in the Book module.

I recommend using collections to group together the photos you want to include in a book project, in which case the option to delete the source photo wouldn’t be available. Instead, if you right-click on a photo while browsing a collection you’ll have the option to remove the photo from the collection. You would need to go to the source folder (such as by right-clicking on the image and choosing “Go to Folder in Library” from the popup menu) in order to be able to delete the source image.

However, even if you’re working with images in a folder rather than a collection, the “Remove Photo” command is not available in the Book module. The Remove Photo command can be found on the Photo menu on the menu bar, but only when you are in the Library or Develop modules. Right-clicking on a photo in a folder will bring up a popup that includes the “Remove Photo” command, but it will be disabled if you are in the Book module.

I’m not sure why the Book module seems to have a unique status in terms of not being able to access the “Remove Photo” command. But again, I do recommend using a collection to group photos for a project such as for the Book module, rather than working directly with folders.

Thumbnails for Layer Masks

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Today’s Question: I’ve noted since the last Photoshop update that layers that have a layer mask now appear with the layer mask icon rather than the black and white thumbnail reflecting the layer mask. Is there any way to change this?

Tim’s Quick Answer: Yes, you can enable the thumbnails for your layer masks in the Layers Panel Options dialog.

More Detail: You can choose the size for thumbnails on the Layers and Channels panels based on your preference, including a “None” option where image layers and layer masks will simply have an icon rather than a thumbnail that provides a preview of the layer or mask contents.

Start by clicking on the panel popup menu, which is an icon showing four horizontal lines found at the top-right corner of the Layers panel. Choose “Panel Options” from that popup menu, which will bring up the Layers Panel Options dialog.

In this case you’ll want to change the Thumbnail Size option from None to one of the thumbnail options. I personally prefer the largest thumbnail size, but you can try the different options to see what you prefer. Note that you do need to click the OK button in order for the Layers panel to update based on the setting you’ve chosen.

The same thumbnail options are available for the Channels panel as well, which you can access by choosing “Panel Options” from the panel popup menu for the Channels panel.

Download from Smartphone Before Import

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Today’s Question: Why not download [photos from a smartphone] with Lightroom Classic? It is the same process and saves a step.

Tim’s Quick Answer: The main reason I don’t import photos into Lightroom Classic directly from a smartphone is that there isn’t an option to delete the photos from the smartphone once the import is complete. Therefore, I download smartphone photos using other software that allows for deletion, importing into Lightroom Classic as part of this process.

More Detail: With most cameras you can import photos directly from the memory card (or directly from the camera) into Lightroom Classic, and then format the card in the camera to delete the photos so you’re ready to capture new images. That process can be a bit cumbersome on a smartphone, especially with an iPhone, since there isn’t a simple “format card” option for deleting all photos that you’ve downloaded.

Normally I would very much prefer to import into Lightroom Classic directly from the media used to capture the images, but for smartphones I make an exception.

As addressed in yesterday’s Ask Tim Grey eNewsletter, you can use Adobe Bridge to download photos to your computer. For example, you could initiate the download using the Photo Downloader feature in Bridge, with the option to delete photos enabled. Once the download is complete, don’t click on a button in the confirmation dialog for deleting photos, but rather switch to Lightroom Classic. Import the photos into Lightroom Classic, taking advantage of the option to make a second copy of the photos in another location. After that import is complete you can return to Bridge to confirm the deletion of the photos that were downloaded.

I wrote an article that goes through this workflow in detail for the April 2022 issue of Pixology magazine. Pixology is included at no additional cost in the GreyLearning Ultimate Bundle (http://timgrey.me/atg99bundle), but is also available as a standalone subscription (with back issues included) here:

https://www.greylearning.com/courses/pixology-magazine

Removing JPEG From Raw+JPEG

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Today’s Question: In my Lightroom Classic preferences the “Treat JPEG files next to raw files as separate photos” checkbox isn’t checked. My old Sony R1 camera had two modes: JPEG and RAW+JPEG (no RAW only). Each photo has an SR2, XMP, and a JPEG file. Is there a simple way to find and remove the JPG files?

Tim’s Quick Answer: You can most certainly delete the JPEG captures so you’ll be left with only the raw captures (and their associated XMP files). The specific approach you can use depends on the workflow you’ve used, and whether you’ve used that workflow consistently.

More Detail: With the “Treat JPEG files next to raw files as separate photos” checkbox turned off, Lightroom Classic will not import the JPEG images that are part of a Raw+JPEG pair into your catalog. It will, however, copy the JPEG images to the same folder as the raw captures. This creates a situation that isn’t ideal, where you have a potentially large number of JPEG images on your hard drive that aren’t visible in your catalog.

The potential challenge with deleting the JPEG images is that you might have captured other JPEG images that are not part of a Raw+JPEG pair. In other words, you probably don’t want to simply delete all JPEG files on your hard drive, so you’ll need to use an approach that enables you to confirm you’re only deleting the files you don’t need.

If you’re completely sure that you never captured standalone JPEG images with the camera in question, so that all JPEG images from that camera are definitely from a Raw+JPEG pair, then the process can be quite simple. You can synchronize the folder(s) that contain the Raw+JPEG pairs so the JPEG images will be added to your Lightroom Classic catalog. You could then set a filter on the Metadata tab of the Library Filter bar so that you are only seeing JPEG files that were captured with the camera in question (using the File Type and Camera options for two of the columns for filtering). With that filter set you could select all the images and delete them.

If you don’t have the confidence that all the JPEG images from that particular camera were part of a Raw+JPEG pair, then you’ll have a bit more work to do. In that case I would still suggest synchronizing the folder (even if you synchronize the top-level folder that represents the hard drive, for example) to bring the JPEG images into Lightroom Classic. You could then sort by capture time and review the images to ensure there is an associated raw capture right next to them, and mark for deletion (such as with a Reject flag) only the JPEG images that do have a corresponding raw capture. You could then delete all the photos you marked for deletion once you’re finished with that review.

Downloading from Smartphone

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Today’s Question: You showed how to use Bridge to import from your phone before importing to Lightroom Classic catalog. Can I assume you have your phone physically attached to your laptop for Bridge to include it the list of devices?

Tim’s Quick Answer: Yes, you need to have your smartphone physically connected to the computer to download photos, unless your smartphone has a removable memory card you can put into a card reader.

More Detail: I prefer to treat my smartphone as “just another camera”, meaning that when I download photos from my smartphone, I put them into my normal workflow along with all other photos. That also means that I delete the photos from my smartphone after download, just as I format my media cards after downloading the images from my other cameras.

One of the options for downloading photos from your smartphone is to use the Photo Downloader feature in Adobe Bridge, which can be found by going to the menu and choosing File > Get Photos from Camera. This will bring up the Photo Downloader dialog, where you can select the source of photos for the download and configure the settings for that download.

To use Adobe Bridge (or similar software) to download photos in this way you need to physically connect the smartphone to the computer, typically via a USB cable. An exception to this would be smartphones with a removable media card, which is available on some Android-based smartphones, for example. In that case you could simply download from the media card and then delete the photos from the media card after downloading and incorporating the photos into your normal workflow.

Regardless of the specifics of your workflow for downloading smartphone photos, I do highly recommend making sure the photos are backed up to another hard drive as part of the download process, and before actually deleting the original captures from your smartphone.

Note that I covered the process of downloading smartphone photos using Adobe Bridge to then import into Lightroom Classic in the article “Smartphone to Lightroom Classic”, which is featured in the April 2022 issue of Pixology magazine. Pixology is included in the GreyLearning Ultimate Bundle (http://timgrey.me/atg99bundle), but is also available as a standalone subscription here:

https://www.greylearning.com/courses/pixology-magazine

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