CullKit
Star ratings tell you which frames are good. Colour labels tell you what to do with them. A five-star photo is a keeper. But a five-star photo with a red label is a keeper that needs retouching, while a five-star with a green label is client-ready and a five-star with a blue label is one you want on your website. The star says “keep.” The label says “why.”
Colour labels are the most underused sorting dimension in a photographer’s workflow. Most tools support them. Lightroom, Capture One, and Darktable all read them. But photographers who rely on star ratings alone hit the same wall after every culling pass: every keeper is a keeper, and nothing tells you which keeper to open first. Colour labels fix that. They add a second axis of organisation that travels with your metadata from the moment you cull to the moment you deliver.
This article covers how to set up a colour label system for your culling workflow, how to apply labels in CullKit on iPhone, iPad, and Mac, and how those labels carry through to your desktop editor without an extra step.
What are colour labels in photography?
Colour labels are a metadata field that assigns one of five colours to a photo: red, yellow, green, blue, and purple. They come from the Lightroom colour label set, which has become the de facto standard across the photography industry. Capture One uses an equivalent colour tag system. Darktable reads the same label field in XMP sidecars. Even Photo Mechanic, which uses its own eight-colour class system, maps its classes to colour labels when writing to XMP.
Labels are not ratings. A star rating says how good a frame is relative to others in the set. A colour label says what stage the frame is at in your workflow, or what it is destined for. You can have a one-star frame with a green label meaning “client delivery” and a five-star frame with a red label meaning “needs retouching.” The two scales are independent and you can filter by either one or both together in Lightroom, Capture One, and CullKit.
In CullKit, colour labels are written to XMP sidecar files alongside your RAW images. An XMP sidecar is a small text file, typically a few kilobytes, that sits next to the RAW on disk. If your file is P12345.CR3, the sidecar is P12345.CR3.xmp. Inside that file, the colour label is stored as a standard xmp:Label field with the value Red, Yellow, Green, Blue, or Purple. Your desktop editor reads this field and displays the corresponding colour swatch in the grid and the metadata panel.
How are colour labels different from star ratings and flags?
All three metadata dimensions serve a different purpose in the culling workflow. Understanding the distinction is the first step to using all three together.
Star ratings answer “how good is this frame?” Use the full zero to five scale to rank frames within a shoot. Five stars for the absolute best, three stars for solid coverage, one star for “technically usable but not a standout.” Star ratings are relative: a five-star frame in a studio session might be a three-star frame on your best outdoor shoot. They are for you, the photographer, to signal editorial quality to yourself.
Reject flags (or pick flags) answer “should this frame survive the cull?” They are binary: keep or discard. Use them during the fast first pass to remove blinks, missed focus, duplicates, and test shots. Flags are the first decision you make on a frame and the fastest: swipe left, gone. Swipe right, it stays.
Colour labels answer “what happens to this frame next?” They are for workflow state, not quality. A frame with a green label is ready for the client gallery. A frame with a red label needs Photoshop time before it is shown to anyone. A frame with a purple label is a black and white candidate. Labels are the bridge between culling and editing: they tell you which frames to open first when you sit down in Lightroom.
All three travel together in the same XMP sidecar. A single frame can carry five stars, a pick flag, and a blue label. Lightroom sees all three. Capture One sees all three. You filter on whichever dimension answers your current question.
How to set up a colour label system for your workflow
The labels are fixed, five colours, but what they mean is yours to define. The most effective label systems are consistent across every shoot. If yellow always means “client gallery” in your studio, then yellow means “client gallery” in every Lightroom catalogue you own. Inconsistency defeats the purpose of labels because you cannot filter with confidence.
Here are three label systems that work for different types of photography. Pick one, adapt it, and stick with it.
System 1: Delivery pipeline (wedding and event photographers)
| Colour | Meaning |
|---|---|
| Green | Client-ready. Ready for gallery delivery with no further work. |
| Yellow | Needs basic edit. Standard colour grade and cropping, no retouching required. |
| Red | Needs retouching. Skin cleanup, background distraction removal, or compositing work. |
| Blue | Personal portfolio. A frame you want for your website or Instagram regardless of client selection. |
| Purple | Black and white candidate. Try this as a monochrome before deciding on the final edit. |
This system works for volume shooters who need to sort 200 keepers into the right post-production queue. After the culling pass, filter to green labels and export immediately for same-day previews. Filter to red labels and batch-send to your retoucher. The queue is built during the cull, not during the edit.
System 2: Client selection (portrait and headshot photographers)
| Colour | Meaning |
|---|---|
| Green | Client shortlist. The frames the client will see in their online gallery. |
| Yellow | Alternate poses. Show these if the client asks for more options from a specific set. |
| Red | Needs retouching before client delivery. |
| Blue | Studio portfolio. For your website, marketing materials, or print portfolio. |
| Purple | Stylist or hair and makeup reference. Useful for editorial and commercial jobs. |
Portrait photographers often need to show clients a curated selection, not a full unrated folder. Colour labels let you build that selection during the cull, on an iPad, before a single file reaches Lightroom. Hand the iPad to the client with the green-filtered gallery open and they swipe through exactly the frames you chose.
System 3: Edit stages (commercial and editorial photographers)
| Colour | Meaning |
|---|---|
| Green | Final selects. Approved by art director or client, ready for final export. |
| Yellow | First edit pass complete. Needs second review or client approval. |
| Red | Raw processing needed. Capture One or Lightroom adjustments before Photoshop. |
| Blue | Compositing required. Multi-shot composite, background replacement, or heavy manipulation. |
| Purple | Archive reference. Keep in the catalogue for future reference, not for this delivery. |
This system maps to the stages a commercial image passes through from raw file to final delivery. You can filter by label at any point to see exactly how many frames are at each stage, which is useful for estimating delivery timelines to clients.
CullKit is an independent product. It is not affiliated with or endorsed by Adobe Inc., Capture One A/S, or any other software vendor. Colour labels in CullKit use the standard Lightroom palette and are written as standard XMP metadata fields. Compatibility claims only.
How do I apply colour labels in CullKit?
CullKit uses the five-colour Lightroom palette, the same set of colours your desktop editor expects. Labels are available in the Pro tier, alongside star ratings, reject flags, and text tags. They are applied during the culling session and written to XMP sidecars at session completion.
On iPhone and iPad, the colour label controls sit in the quick-access bar below each frame in the culling interface. While you are culling, tap the label icon to open the colour picker. Tap a colour to assign it. The label dot appears on the frame immediately. You can change the label at any time before the session ends by tapping the same icon and picking a different colour. The quick-access bar can be configured to show the label picker as a primary control, so you can assign a label with a single tap during the culling pass.
On Mac, keyboard shortcuts drive the workflow. After you have assigned a star rating to a frame, press the label shortcut key to cycle through or select a colour. The label appears as a coloured dot in the grid view and in the metadata panel. If you prefer to rate first and label second, work in two passes: a fast star-rating pass over the full session, then a colour-label pass over the unrated subset to organise the keepers.
In batch review, before you finish the session, CullKit shows you a grid of your rated and labelled frames. This is the moment to spot-check your labels. If a frame got the wrong colour, tap or click it and change the label before the session writes metadata. Once the session is finalised, labels are written to XMP sidecars alongside your RAW files.
Colour labels also appear as small dots on thumbnails in the grid view and the folder browser, so you can see your label distribution at a glance before opening a folder.
How do colour labels transfer to Lightroom, Capture One, and Darktable?
The handoff is automatic because labels are stored in a standard XMP field. After you finish a CullKit culling session, the XMP sidecar for each frame contains the colour label alongside the star rating, flag, and tags.
Lightroom Classic. If you are importing the folder for the first time, Lightroom reads the sidecars during import and applies labels to each frame. Colour swatches appear in the grid view and you can filter by label colour using the Attribute filter in the Library module. If the folder is already in your catalogue, select it in the Library module, then choose Metadata > Read Metadata from Files. Lightroom re-reads the sidecars and applies any new or changed labels.
Capture One. Colour labels transfer as colour tags during import. Capture One maps the XMP label field to its own colour tag system. The colours match: red, yellow, green, blue, and purple. You can filter by colour tag in the Filters tool or create smart albums based on label colour. If you need to re-read metadata for images already in a session or catalogue, select them and choose Image > Load Metadata.
Darktable. Darktable reads colour labels from XMP sidecars directly. Open the folder in the lighttable view and the colour labels appear automatically in the metadata panel and as coloured borders on the thumbnails. No import step needed. Darktable also writes colour labels back to XMP, so any label changes you make in Darktable are persisted to the same sidecar file.
The label you set during culling is the label that appears in your editor. If you change the label later in Lightroom, the change is written to the catalogue, not to the XMP sidecar, unless you have Lightroom set to automatically write XMP. To write the updated label back to the sidecar and keep CullKit and Lightroom in sync, select the frame in Lightroom and choose Metadata > Save Metadata to File, or enable the “Automatically write changes into XMP” option in Catalogue Settings.
Troubleshooting colour labels
I assigned a label in CullKit but it does not show in Lightroom. The most common cause is an unfinished culling session. CullKit writes sidecars only when the session completes. If the session was interrupted, return to it, finish it, and the sidecars will be written. If the session completed, select the folder in Lightroom’s Library module and run Metadata > Read Metadata from Files. Lightroom will pick up the labels immediately.
Lightroom shows a different colour than what I assigned. This can happen if Lightroom’s colour label set has been customised. By default, Lightroom uses the standard red, yellow, green, blue, and purple set. If you or a preset changed the label names in Metadata > Color Label Set, the mapping between the XMP field value and the displayed colour might be off. Reset the label set to “Lightroom Default” in the menu bar under Metadata.
Capture One does not show labels on existing images. Select the images and run Image > Load Metadata. If that does not work, check that the XMP sidecar files are in the same folder as the RAW files. Capture One reads sidecars that share the same base filename as the RAW.
CullKit assigned a label but another tool overwrote it. CullKit writes labels at session end only. If you open the folder in another application after the session and that application writes to the same sidecar, it may overwrite CullKit’s label. When CullKit writes sidecars, it downloads the existing sidecar first, merges its own data in, and writes the combined result. But if another tool writes to the sidecar after CullKit, the last writer wins. Establish a one-way workflow: cull in CullKit first, then import into your editor.
Can I use colour labels on a Synology NAS? Yes. CullKit writes XMP sidecars to the same folder as your RAW files, whether that folder is on a Synology NAS over SMB, a QNAP, a TrueNAS, a UGREEN, a local drive, or an external SSD. The label is stored in the sidecar. The sidecar sits on disk. Your editor reads it from disk. The storage medium does not matter. For more on NAS workflows, see the NAS rating guide on this blog.
Related reading
- The Best Way to Rate Photos on a NAS - star ratings, reject flags, and colour labels on network-attached storage, with per-vendor SMB paths.
- The Wedding Photographer’s Culling Workflow - a two-pass culling strategy that pairs star ratings with colour labels for fast client delivery.
- XMP Sidecar Workflow: From Cull to Lightroom in One Step - how XMP sidecars carry ratings, labels, and tags between every tool in your workflow.
Label your workflow, not just your photos
Star ratings tell you what to keep and what to discard. Colour labels tell you what to do next. A green label on a three-star frame is an actionable instruction: this is ready for the client. A red label on a five-star frame is a different instruction: this is the shot, but it needs work first. When your labels are consistent across every shoot, your editing queue organises itself during the cull. You open Lightroom, filter by colour, and start editing the frames that actually need you.
CullKit is available on the App Store for iPhone, iPad, and Mac. The free tier lets you browse any connected library: Synology Photos, any SMB NAS share, local folders, and external SSDs. The Pro tier (7-day free trial, then monthly or yearly) unlocks the full label and rating workflow: star ratings, reject flags, five colour labels from the Lightroom palette, free-text tags, and XMP sidecar writing ready for Lightroom, Capture One, and Darktable.
Download CullKit on the App Store
CullKit is an independent product. It is not affiliated with or endorsed by Adobe Inc., Capture One A/S, or Darktable. Colour labels use the standard Lightroom palette and are written as standard XMP metadata fields compatible with Lightroom, Capture One, and Darktable. Compatibility claims only.