# Analyzing Frames Source: https://cadmium.mintlify.app/analyzing-frames Segment your line artwork for colorization Analysis is a crucial step in the coloring process. In order for Cadmium to infer predictions about how to color frames, the images need to be interpreted as multiple regions or "segments." Comparing these segments in the reference image with the segments in the target image is the basis for Cadmium's color predictions. ## When Does This Happen? Whenever you have a line frame with no corresponding imported color frame, that frame needs to be analyzed. Analysis occurs when you: * Press the **Analyze** button on the current frame or selected frames * Press the **Colorize** button (analysis is triggered automatically) It's often helpful to analyze first — before colorizing — to see how your artwork is being interpreted. This lets you spot gaps and saves time and credits. Cadmium saves a copy of your analyzed segment map, but if the line image is altered or analysis settings change, a new segmentation map will be needed. ## Analysis Settings Panel Analysis Settings Panel How the image is segmented depends on how the line image is interpreted. Adjust settings in the **Analyze Settings** panel in the upper-right corner: Determines how opaque a line image pixel needs to be to count as part of a segment boundary. **Auto** mode uses an algorithm to adjust brightness and contrast. **Manual** mode lets you set a thresholding alpha value between 0 and 255 — higher values include more semi-transparent pixels. Like many animation programs, this determines the size of a gap between pixels to be considered closed. Uses an algorithm based on the Trapped Ball method. The smallest number of pixels allowed in an individual segment. Any segment below this threshold is dissolved and combined with a neighboring segment. Useful for charcoal-like line quality that creates many small unintended segments. On by default. When you press **Analyze**, each segment is colored a different random color. This helps quickly identify gaps in your artwork. Note that it replaces any existing color frames, so turn it off if you want to preserve them. After this step, you're ready to [colorize your frames](/colorizing). # Change Log Source: https://cadmium.mintlify.app/changelog Release notes and updates This changelog provides a detailed history of updates and improvements to Cadmium. *** ## 1.5.0 **January 17, 2026** * **New feature**: AI gap closer more intelligently closes gaps in artwork * Bug fixes * Updated software packages for improved stability ## 1.4.1 **September 9, 2025** * Fixed issues with editing the color palette, changing and removing colors * Added a welcome modal with sample file ## 1.4.0 **September 1, 2025** * MP4 export now works on Windows * Enhanced Line Layer colorization is much faster, responsive to color tolerance slider, and no longer beta * Addressed bugs and issues with timeline selection and deletion * Single click on swatch now loads color * Added variable framerate playback and MP4 export * Added ability to add in/out points to playback ## 1.3.2 **August 27, 2025** * Fixed issues related to drawing on hidden layers * Fixed MP4 export for Windows * Improved wait screen information * Improved enhanced line colorization ## 1.3.0 **August 14, 2025** Cadmium is out of beta! ## 1.2.0 **August 14, 2025** * Fixes related to behavior when closing laptop lid or losing internet connection * Improved cancellation logic * Increased free tier max resolution to 4K ## 1.1.0 **August 8, 2025** * Upgraded to faster, more powerful GPU servers * New GPU-powered model — more accurate with complex characters and motion * EL line fixes — automatic line colorization now works reliably * Built-in licensing — supports credits, free tiers, and unlimited Pro plans ## 1.0.0 **July 1, 2025** Initial public release of Cadmium. *** ## Pre-Release Versions ### 0.3.4 **February 19, 2025** * **Speed boost**: now 2x faster to analyze images * Various bug fixes ### 0.3.3 **November 29, 2024** * Added reference frame toggle button * Fixed server bug that was occasionally preventing users from colorizing * Improvements to the Enhanced Line feature * Automatic line analysis threshold improves performance without adjusting settings ### 0.3.2 **August 24, 2024** * **Colorize speed boost** — 4K images are now easier to process * Improved error handling * Added user ID lookup for better tech support ### 0.3.1 **May 2, 2024** * Stop button actually works now * Cadmium is now completely cloud-based and works on any machine with internet access * Improved analysis settings — better gap closing, adjustable alpha sensitivity * Improved error handling and bug fixes ### 0.3.0 **March 15, 2024** This release is not backwards compatible with files saved from earlier versions. Please complete any work in progress and export before upgrading. * Lightning fast cloud colorization * Line coloring engine (experimental) * Works for any version of macOS on Intel or M1 * Native Apple M1 acceleration support * Adjustable segmentation size threshold ### 0.2.15 **October 19, 2023** * Added reference panel for easier color picking * Updated the updater for smoother, more transparent process * Fixed issue preventing saving/opening older or cross-machine projects * Updated Japanese translation ### 0.2.14 **September 21, 2023** * Improved temp file storage and removal * Updated export functionality * Japanese language support ### 0.2.13 **September 2, 2023** * Fixed an error that was causing files to not load properly, leading to issues with colorizing ### 0.2.12 **July 28, 2023** * Fixed SVG export bug * Fixed bugs to allow import of color images without line images * Completely rewrote the Cadmium AI engine to operate more efficiently and accurately ### 0.2.11 **July 29, 2023** * Added eraser tool * Fixed drawing bugs — pen now operates more smoothly and reliably, frames don't get deleted * Fixed playback issue where frames misalign * Improved update flow * Added recently opened files to menu ### 0.2.10 **July 8, 2023** * Color frames are now analyzed on import * Import color sequences without a line sequence and export with colors separated * Speed increase on colorizing frames * Fixed color palette bugs * Timeline frame behavior updates ### 0.2.9 **June 22, 2023** * **Speed boost** on frame analysis — up to 6x faster * New welcome tour for easier onboarding * Bug fixes and improvements to color palette processing ### 0.2.8 **May 8, 2023** * Patched a critical bug that would sometimes reset Cadmium when typing in a text field ### 0.2.7 **April 14, 2023** * Added global color palette — change individual colors throughout the sequence with one click * Tool menus can be dragged and dropped to either side of the window * Color palette swatches can be reordered * Export colors separated ### 0.2.6 **March 20, 2023** * Added ability to save and open Cadmium files * Added `Cmd + right-click drag` shortcut to change brush size * Added ability to hide/show timeline (`T`) * Added secondary saved color with toggle (`X`) ### 0.2.5 **March 9, 2023** * Canvas view can now be reset from View menu * Current background color now shown in color picker * Fixed bug with rapid zoom in/out * Fixed auto-updater bug * Undo/redo with 5 states ### 0.2.4 **March 6, 2023** * Undo/redo support (up to 5 states) * Fill tool now synchronized with Cadmium AI Core * Pen tool improvements * Settings saved and restored after quit * Various UI updates ### 0.2.3 **February 28, 2023** * Improved and updated tool shortcuts * Active layer functionality — ability to draw on either layer * MP4 video export * Improved SVG export — more accurate and faster * Added UI for auto-updater ### 0.2.2 **February 21, 2023** * Added color palette feature — colors added when fill or pen tool is used with a new color, and when sequences are colorized * Added SVG vector export at three quality levels ### 0.2.1 **February 12, 2023** * Fixed an issue where Cadmium could not analyze or colorize on macOS due to Apple system integrity protection ### 0.2.0 **February 4, 2023** First beta release of Cadmium. # The Color Menu Source: https://cadmium.mintlify.app/color-menu Color wheel and palette management The Color Menu is a central feature of Cadmium. It contains a **color wheel** where you can choose, adjust, and input color values, and a **Palette** where Cadmium keeps track of all colors in your file. Color Menu Interface ## The Color Wheel The Color Wheel can be interacted with to choose new colors, and there's an input box for copy-pasting hex codes. * The **large color block** below the wheel displays the currently selected color. * The **small rectangle** on the right is the secondary color — click it or press **X** to swap. * Below this, you can set the canvas background color to the currently selected color. ## The Color Palette Any time a new color is introduced to your frames (via a reference image, or by selecting from the color wheel), a swatch appears in the Palette. * **Click** a swatch to select it * **Drag** to reorder swatches * **Double-click** to change the currently selected color to this swatch * **Change Color** — select the swatch you want to change, pick a new color, and press the "Change Color" button to globally replace it * **Simplify Palette** — finds near-neighboring colors and merges them into one * **Shift-click** to select multiple swatches, or use the **Select All** button * **Delete Color** removes any selected swatches # Colorizing Source: https://cadmium.mintlify.app/colorizing Automatically color your frames using reference images ## Colorizing Frames Colorizing Interface Once you have your imported line sequence and at least one color reference, you're ready to colorize. You can colorize a single frame or multiple frames at once. * Pressing **Colorize** with no frames selected will default to the current frame. * Select multiple frames or all frames to process in batch. When multiple frames are selected, Cadmium first uses your reference image, then subsequently uses the last colorized frame as a new reference for the next frame. Because of this, errors can compound and results may become less accurate as the sequence progresses. Start by colorizing just 1 or a few frames to see how well everything performs. Make any manual corrections before continuing. See the [Editing Frames](/editing-frames) section for details. ## Which Reference Frames Are Being Used? Reference Frame Connections The timeline displays line connections that visually show which frame is being used to make predictions. It will always be the reference frame closest to the current frame you are coloring. You cannot re-colorize a frame that is marked as a reference frame. You must first make it a non-reference frame or delete it. # Drawing Tools Source: https://cadmium.mintlify.app/drawing-tools Pen, eraser, fill, and eyedropper tools ## Pen Tool Pen Tool * Toggle between draw and erase mode with **Alt/Option**. * Adjust pen size with the slider, or while the pen is selected, hold **Control** and right-click drag left/right. * Pressure sensitivity can be toggled on and off from the pen panel. ### Draw Options There are three drawing modes: | Mode | Behavior | | ---------- | ----------------------------------------------------------- | | **Over** | Normal drawing — new strokes are drawn over existing pixels | | **Under** | Draws behind any existing pixels | | **Within** | Confined to only existing pixels | ## Eraser Tool Eraser Tool A dedicated eraser tool with its own size setting, independent of the pen tool. ### Common Uses for Pen and Eraser After analyzing your frames, you may find gaps in your linework. In addition to adjusting the [Analysis Settings](/analyzing-frames#analysis-settings-panel), you can use the pen and eraser to make manual corrections. You can also use the pen on the Color Layer for small tweaks. Note that drawing on the color layer does not currently update the segmentation mask, so manual changes may not persist through re-colorization. ## Fill Tool Fill Tool Regardless of which layer is selected, the fill tool always fills on the **Color Layer**. It corresponds to the segment map of each image, and changes made with this tool propagate to other frames when used as a reference. ## Eyedropper Eyedropper Tool The eyedropper samples any color on the canvas. Hold **Shift** as a shortcut to eyedrop while using another tool. # Editing Frames Source: https://cadmium.mintlify.app/editing-frames Make manual adjustments to line and color frames ## Editing Line Frames After analyzing your frames, you may find some gaps in your line work. In addition to adjusting the [Analysis Settings](/analyzing-frames#analysis-settings-panel), you can use the Pen/Eraser tool to make manual adjustments. Make sure you have the **Line Layer** selected, then select the Pen tool to adjust. ## Editing Color Frames When the **Color Layer** is selected, you can use the pen tool and the fill tool to edit your color frame. You can manually change the color of segments using the fill tool. See the [Drawing Tools](/drawing-tools) section for more information about available tools and their options. # Exporting Source: https://cadmium.mintlify.app/exporting Export your colored frames for your pipeline ## Exporting Frames When you've finished the coloring process, export your frames by pressing the **Export** button in the lower-right corner, or via the menu: **File > Export**. Whichever layers are currently visible in your timeline is what will be exported. ### Export Colors Separated Export Options If you need to export all individual colors separately for your compositing process, click the arrow on the Export button and select **Export Colors Separated**. This will export each individual palette color into its own separate folder at your specified location. # FAQ Source: https://cadmium.mintlify.app/faq Frequently asked questions Cadmium accepts **PNG format with alpha** only. Make sure your frames have a number sequence at the end of the file name, like `fredDog_001.png`. Double check that your line layer images have an **alpha channel**. Without it, the color layer won't be visible. You must include a **reference image** for Cadmium to know how to color. On Windows, you may also need to allow permissions in your firewall settings. When you select an image to color, the lines show which frames are being referenced to inform how that frame should be colored. It's a visual cue showing Cadmium's prediction source. Any time a new object or color is introduced into your scene, you should provide a reference. The more references you provide, the better Cadmium will perform. Pressing **Analyze** creates a segment map and returns a color map of how Cadmium interprets separate regions. The random colors help you quickly spot gaps in your artwork. This is necessary for the colorizer to work. You may need more reference frames, or there may be gaps in your line work (use the pen tool to close them). Check your [Analysis Settings](/analyzing-frames#analysis-settings-panel) for gap closing options. You can learn more about this in the [Analyzing Frames](/analyzing-frames) section. Cadmium relies on your internet connection to process frames. On average, one HD frame takes around 5 seconds. If you're processing very large frames, consider down-resizing before import. Click on the **layer name** to select the active layer — that's where drawing will happen. The fill tool, however, always works on the color layer regardless of which layer is selected. For the initial release, the focus was primarily on coloring functionality. Better drawing tools are on the roadmap. We're sorry! Please email us at [hello@cadmium.app](mailto:hello@cadmium.app) and we'd be happy to help you troubleshoot. # Getting Started Source: https://cadmium.mintlify.app/getting-started Installation, setup, and account creation Cadmium is a desktop application that runs on Mac or PC. A stable internet connection is required for the application to function properly. ## Installation and Setup To install Cadmium, follow the steps for your operating system: 1. Download the installer from the [Cadmium website](https://cadmium.app). 2. Run the installer and follow the on-screen instructions. 3. The application will be installed in the default directory (`C:\Program Files\Cadmium`). 4. Temporary files for session data are stored in `C:\Users\\AppData\Roaming\Cadmium`. 5. The installer updater is stored in `C:\Users\\AppData\Local\cadmium-updater\`. 1. Download the macOS installer from the [Cadmium website](https://cadmium.app). 2. Open the downloaded DMG file. 3. Drag and drop the application into the Applications folder. ## Account Creation and Management Once you have installed the application: 1. Launch the application from your Start Menu (Windows) or Applications folder (macOS). 2. You will be prompted to log in or create a new account. ### Creating a New Account If you don't have an account, click the **Create Account** button on the login page. Fill in the required information, and you'll receive an email to verify your account. ### Logging In If you already have an account, enter your credentials and click the **Log In** button. That's it — you're now ready to start using Cadmium! # Importing Frames Source: https://cadmium.mintlify.app/importing-frames Import line artwork and color frames into Cadmium In order to work in Cadmium, you need to import frames. You can import to both the line layer and the color layer. It is usually recommended to first import your line images to the line layer. ### File Type * Export your line frames from your animation software of choice. Make sure they are exported as **PNG with alpha**. Place your images in a unique folder and make sure the frames are numbered, starting with 1 (e.g. `sharkdadLine_001.png`). * **Pro users**: image sizes up to 4K UHD (7680 x 4320 pixels or equivalent aspect ratio). The free tier is limited to HD (1920 x 1080). ## Importing Images to the Line Layer Importing to Line Layer Most often, you'll want to start by importing frames to your line layer. In the menu, click **File > Import > Line Layer**. Or you can simply select a folder with your images and drag it into the drop area on the timeline. ## Importing Images to the Color Layer Importing images to the Color Layer is primarily for providing a reference for how Cadmium should color your frames. Read more about [Reference Frames](/reference-frames). You can also import color images before line images. In this case, Cadmium will attempt to retroactively create a line image from your color frame. This is not commonly used, but some users find it helpful to manipulate colors or export each color separately from an already colored sequence. ## Importing Images to the Reference Panel Reference Panel Import Sometimes you might have style frames of your animation that are not within your sequence, but you want to reference the colors. You can import these into the **Reference Panel**, found in the top-right corner. In the **Library** dropdown, click the **+** sign to add a reference image. You can middle-mouse scroll to zoom in and out, or use the zoom tool. Resize the panel by hovering over its edges and dragging. The eyedropper tool works here as well. ## Duplicate Frames When you import a line or color image sequence that has multiple duplicates (common in cel animation for timing), Cadmium will recognize concurrent duplicate frames and "de-duplicate" them — extending the image as one selectable block. This preserves your animation timing while simplifying the coloring process. If your sequence has duplicate images that are *not* next to each other (like a looping cycle with repeated frames), Cadmium will recognize these as "clones." Whatever you do to one frame will apply to all its clones. Selecting one of these frames will automatically select the others. # Introduction Source: https://cadmium.mintlify.app/index Welcome to Cadmium — color your animation with AI Cadmium — color your animation with AI ## About Cadmium Cadmium is a creative tool for hand-drawn animation. Assisted by AI, you can color your entire sequence from just a few keyframes. It was developed to help traditional animators digitally color their line frames. By automating repetitive tasks, Cadmium allows artists to focus on being creative. ## Key Features Import your line artwork as numbered .png sequences with an alpha channel. Import or create a reference frame within Cadmium to define the color of each segment on your image. Define a "segment map" of your line image, identifying all boundaries of areas that can be colored uniquely. Based on your reference image, Cadmium predicts color choices for uncolored frames — sequentially or one at a time. Use drawing tools to manually adjust line work and colors for pixel-perfect results. Export your work to integrate back into your pipeline. Each color can be exported separately if desired. ## Contacting Support If you encounter any issues or have questions not covered in this documentation, contact us at [hello@cadmium.app](mailto:hello@cadmium.app). # Keyboard Shortcuts Source: https://cadmium.mintlify.app/keyboard-shortcuts Quick reference for all keyboard shortcuts Below is the complete list of keyboard shortcuts for Cadmium. On Mac, substitute **Cmd** for **Ctrl**. ## Playback & Navigation | Action | Shortcut | | -------------------------- | ------------------------------------------------- | | Play/pause | `Enter` | | Next/previous unique frame | `Left/Right Arrow` | | Next/previous single frame | `Shift + Left/Right Arrow` | | Change active layer | `Ctrl + Up/Down Arrow` or `Shift + Up/Down Arrow` | | Hide/show timeline | `T` | ## Canvas | Action | Shortcut | | --------------- | --------------------------------------- | | Hand tool (pan) | `Space` (hold) | | Zoom tool | `Z` (+ `Alt` to zoom out) | | Zoom in/out | Middle mouse scroll or right-click drag | ## Selection | Action | Shortcut | | ---------------------------------- | ---------------------------------------------------------- | | Select all frames on current layer | `Ctrl + A` | | Deselect frames on all layers | `Ctrl + D` | | Delete frame | `Delete` | | Toggle reference frame | Right-click on frame, or diamond button next to layer name | ## Drawing Tools | Action | Shortcut | | -------------------------- | ------------------------------------------------- | | Pen tool | `B` | | Toggle pen erase/draw mode | `Ctrl + B` or hold `Alt` while drawing | | Adjust pen size | `Ctrl + right-click drag` (while pen is selected) | | Eraser | `E` | | Fill tool | `F` | | Fill tool mode toggle | `D` or `Alt/Option` | | Eyedropper tool | `I` (or `Shift` while pen/fill tool is selected) | ## Color | Action | Shortcut | | ------------------- | -------- | | Color wheel | `C` | | Toggle active color | `X` | ## System | Action | Shortcut | | ------------ | ------------------ | | Undo | `Ctrl + Z` | | Redo | `Ctrl + Shift + Z` | | Force reload | `Ctrl + Shift + R` | Keyboard shortcuts are not customizable at this time. # The Line Colorization Menu Source: https://cadmium.mintlify.app/line-colorization-menu Automatic line coloring and enhanced line features The Line Colorization is an experimental feature that enables automatic coloring of line work, similar to programs like PaintMan. If your linework uses different colors to indicate how lines should be recolored, this feature is for you. ## Enabling Line Colorization Line Colorization Button Access the line colorization feature by pressing the button in the upper-right corner. Alternatively, click the **star icon** next to the Outlines Layer name. Layer Toggle When the feature is enabled, a third set of frames appears above your line frames on the timeline — the **Enhanced Line (EL)** layer. Enhanced Line Layer ## Working with the Enhanced Line Layer When in EL mode, any actions on the line layer apply to the Enhanced Line layer: * Use the **pen tool** to manually color lines (note: the pen only draws "within" on the EL layer). * Use the **fill tool** on the EL layer to fill the line work surrounding a segment with the selected color. ### Enhanced Line Color Palette EL Palette Controls You can draw over any existing line that matches a color in your Enhanced Line Color palette. By default, Red, Green, and Blue are selected. You can add other colors or temporarily disable any by pressing the palette icons. For example: if your line work is red and black and only red is in your EL palette, you can only edit the red lines. Add black to edit those as well. Turn off the normal line layer visibility to isolate what is being edited on the EL layer vs. the normal line layer. ## Extracting Lines from Color Frame on Import If the last toggle button in the menu is enabled, you can extract EL line colors from a color image: 1. Import your line images as normal. 2. Enable Line Colorization, and enable **Extract Lines From Color On Import**. 3. Import a color image that contains colored line work as you want the final image to look. Your colored line work will appear on the EL layer, separated from normal line work, with colors perfectly separated. Cadmium will automatically detect your EL colors — no need to manually add them to the palette. ## Colorizing Line Work You can automatically colorize line work the same way you colorize fills. If the EL layer is activated, pressing **Colorize** will also process the line work. This can take longer depending on image complexity. Also note that if you color line work around a segment and that line work is continuous and the same color, it will all be filled. The initial line work needs a color change for Cadmium to know where to stop. # Reference Frames Source: https://cadmium.mintlify.app/reference-frames Provide color references for Cadmium's predictions ## What is a Reference Frame? In order for Cadmium to color your frames, it needs an example of how they should be colored. Reference frames are denoted on the timeline with a **purple dot**. You can import one or multiple reference frames by dragging them onto the color layer. These reference frames must be numbered in order to appear in the correct position on the timeline (e.g. `reference_04.png` will appear at frame 4). You can also color your own reference frames directly in Cadmium. ## Preprocessing Color Frames Once you've selected or dragged your image to the color layer, Cadmium will "preprocess" the color frame. If there is a corresponding line image, the line image defines the color boundaries of your reference image, and the most prominent color in each segment will be filled in. Your color palette will also populate with all of the colors. ## Creating Color References There are two ways to create color references: 1. **Import a frame** — Any color frame you import to the color layer becomes a reference frame. 2. **Color manually** — Paint a frame directly in Cadmium to create a reference. Right-click on any color frame to change whether or not it is a reference. ## Reference Panel Reference Panel If you have a style frame of how you want your character to look, but the frame is not part of your animation sequence, you can import it into the **Reference Panel**. The button to open it is in the top-right corner next to the help button. To add images, press the **+** icon in the **Library** dropdown and navigate to your file. You can import multiple style frames at once, selecting the filename you want to view. Zoom in with the zoom tool or middle-mouse scroll. The eyedropper lets you select colors from your reference image to apply to the canvas. # User Interface Source: https://cadmium.mintlify.app/user-interface The Canvas, Timeline, Layers, and Key Frames ## The Canvas The Canvas As soon as you have imported artwork into Cadmium, the canvas will become visible, displaying your artwork. There are a few tools associated with how you view the canvas in the sidebar on the left side of the application. ### Hand Tool Like other drawing programs, the hand tool allows you to move around your canvas by left-clicking and dragging. The shortcut is holding **Space**. ### Zoom Tool The Zoom tool zooms in and out (toggled by **Alt/Option**). You can also use the middle mouse scroll, or right-click and drag to zoom in and out of the canvas. ### Eyedropper The eyedropper tool allows you to sample any pixel color on the canvas. If a semi-transparent pixel is sampled, the eyedropper will return the full color value of the pixel. By default, the background color of the canvas is white, but you can change it in the [Color Menu](/color-menu). *** ## The Timeline The Timeline The timeline displays graphical representations of your animation frames and allows you to select, remove, and navigate between frames. * Show or collapse the timeline by clicking the arrow in the top-left corner, or pressing **T**. * Once images are imported, the timeline displays the image size next to the collapsible arrow. * Press **Enter** or the play button to play through your sequence at 24 fps. * Use the **Left/Right arrow** buttons to go to the previous or next frame. * Click and drag in the numbered area above the frames to scrub through the timeline. ### Layers The timeline has two layers: one for **color** and one for **line work**. When you start a new file, each layer has a drop zone where you can drag and drop images or folders. ### Layer Visibility Toggle layer visibility by clicking the **eyeball icon** next to each layer. Visibility affects how your images are exported — see the [Exporting](/exporting) section for details. ### Selecting Layers Layer Selection Keep track of which layer is currently selected, as it affects where drawing actions occur. Click on the layer name to select it. **Shift + Up/Down arrows** toggles the selection. ### Outlines Layer This is where you import your line images. The star icon next to the layer name enables an experimental [line colorization](/line-colorization-menu) feature. ### Color Layer Below the Outlines Layer is the color layer — where you import or create reference frames, and where colorized images populate. The **diamond icon** next to the visibility icon indicates a reference frame is selected. A half-filled diamond means both a reference and non-reference frame are selected. Click the diamond to toggle frames as reference images. For more information about working with frames, see the [Importing Frames](/importing-frames) section. *** ## Key Frames Key Frames The gray boxes on the timeline represent your sequence's unique drawings and how many frames they are held for. If you import duplicates of an image, Cadmium will recognize this and group them together. The purple dots represent reference frames used to determine how to color the selected frame. Learn more about [Reference Frames](/reference-frames).