# Scanned Target Measurement Tool Instructions ## Overview The Scanned Target Measurement Tool allows you to extract accurate Lab color measurements from scanned step wedges and color targets. The tool includes built-in scanner calibration using a grayscale step wedge (Kodak/Tiffen Q-13 or similar) to compensate for scanner characteristics and ensure accurate color measurements. ![[ScannerMeasurementTool-Calibrated-Measured.png]] --- ## Getting Started ### Loading Your Scanned Image 1. Launch the Scanned Target Measurement Tool 2. Drag and drop your scanned stepwedge or color target image into the application window 3. The image will be displayed in the main viewing area ### Image Adjustment Controls If the scanned image needs to be straightened or reoriented before measuring, use the controls in the Image Adjustments panel: **Flip** - **Flip Horizontal / Flip Vertical** — Mirror the image along either axis **Rotation** - **90° buttons** — Rotate the image in 90° increments (clockwise or counter-clockwise) - **Fine rotation stepper / text field** — Apply precise sub-degree rotation. Enter a value directly or use the stepper arrows **Perspective Correction (De-Skew)** - Use this when the target was scanned at an angle or with perspective distortion - Click **"Start Perspective Correction"** to enter de-skew mode - Click each of the four corners of the target in order: **Top-Left → Top-Right → Bottom-Right → Bottom-Left** - After each corner, a confirmation dialog appears — click **Continue** to proceed or **Redo This Corner** to re-select - After all four corners are selected, click **Apply Correction** to warp the image - Press **Escape** at any time to cancel de-skew mode _Tip: Apply image adjustments before calibration for the most accurate workflow, though adjustments can also be applied after calibration._ --- ## Sample Modes The tool offers three sampling modes for different measurement workflows, selectable from the **Sample Mode** dropdown: ### Eyedropper Mode (Default) Live Lab readout with point-and-click sampling. **Use case:** Quick spot measurements, verifying specific areas, or exploring color values across the target. **How it works:** - Move your cursor over the image to see live Lab values - Click to record a measurement - Samples a 3×3 pixel area centered on the cursor ### Manual Mode Sample individual patches one at a time using drawn rectangles. **Use case:** Measuring individual patches, spot checking values, or working with irregular target layouts. ### Automatic Mode Define a grid and automatically measure all patches at once. **Use case:** Measuring uniform grid-based targets (like IT8 targets or stepwedges with regular spacing). When you select Automatic mode, a dialog will prompt you to enter the number of **Rows** and **Columns** for your target grid before proceeding. --- ## Scanner Calibration Workflow **Why calibrate?** Scanners introduce their own tonal response characteristics. Calibration ensures your measurements reflect the actual printed values, not the scanner's interpretation. ![[ScannerMeasurementToolDemo.mov]] ### Prerequisites - A grayscale stepwedge with known Lab L* values (Q-13 recommended) - Three reference patches: White (step 0), Mid-tone (step M), and Black (step 19/Dmax) ### Calibration Steps 4. **Load your scanned stepwedge** into the tool 5. __Set reference Lab L_ values_* (default values are for Q-13 stepwedge): - White patch: L* 95.0 - Mid patch: L* 50.0 - Black patch: L* 10.0 _Note: If using a different stepwedge, update these values to match your reference's specifications_ 6. **Click "Start Calibration"** - The tool enters calibration mode - Sample rectangles will display in blue 7. **Sample the White patch (Step 0)**: - Draw a rectangle around the white patch - A confirmation dialog shows the measured L* value - Click **"Continue"** to proceed, or **"Redo Sample"** if the selection was incorrect 8. **Sample the Mid patch (Step M)**: - Draw a rectangle around the mid-tone gray patch - Confirm or redo the sample 9. **Sample the Black patch (Step 19/Dmax)**: - Draw a rectangle around the darkest patch - The final dialog shows all three measurements - Click **"Apply Calibration"** to adjust the image immediately - Or click **"Redo Black Sample"** if needed 10. **Calibration Applied**: - The image is now adjusted using Photoshop-style Levels adjustment - All subsequent measurements will be taken from the calibrated image - The original uncalibrated image is preserved and can be restored ### Calibration Tips - **Sample area size:** Draw rectangles that cover the center portion of each patch, avoiding edges - **Canceling calibration:** Press **Escape** at any time during calibration to cancel and reset - **Resetting calibration:** Use the "Reset Calibration" button to restore the original uncalibrated image --- ## Measuring Your Target Once your image is calibrated (or if calibration isn't needed), you can begin measuring patches. ### Manual Mode Workflow 11. **Select "Manual" from the Sample Mode dropdown** 12. **Draw a sample rectangle:** - Click and drag to define the area to measure - The rectangle displays in red - RGB and Lab values update in real-time 13. **Interactive controls while dragging:** - **Hold Spacebar:** Reposition the sample rectangle without resizing - **Press Escape:** Cancel the current selection 14. **Release the mouse** to record the measurement - Values appear in the measurements table - RGB and Lab readouts show current sample values 15. **Repeat** for additional patches ### Automatic Mode Workflow 16. **Select "Automatic" from the Sample Mode dropdown** - A dialog will appear prompting you to enter the grid size - Enter the number of **Rows** (vertical patches) and **Columns** (horizontal patches) - Click **OK** to confirm — the total patch count updates automatically 17. **Draw a rectangle covering the entire target area:** - Click and drag to encompass all patches - Interactive controls work the same (Spacebar to reposition, Escape to cancel) 18. **Confirm the measurement:** - A dialog shows the total number of patches to be measured - Click **"OK"** to proceed, or **"Cancel"** to adjust the selection 19. **Automatic sampling:** - The tool divides your selection into a grid - Each patch is sampled from its center 50% area (avoiding edges) - Green rectangles show sampled areas - All measurements are added to the table _To change the grid size, simply re-select Automatic mode from the dropdown to bring up the grid setup dialog again._ ### Eyedropper Mode Workflow 20. **Eyedropper mode is the default** when you launch the tool - Or select "Eyedropper" from the Sample Mode dropdown 21. **Move your cursor over the image:** - Lab values update continuously as you move the cursor - Samples a 3×3 pixel area centered on the cursor - RGB and Lab readouts show live values in real-time 22. **Click to record a measurement:** - The current Lab value is added to the measurements table - Continue moving to sample additional points - Each click records a new measurement row **Use case examples:** - Verifying calibration accuracy - Measuring small patches or irregular areas - Exploring tonal transitions - Spot-checking specific color values - Quick measurements without drawing rectangles --- ## Interactive Sample Drawing Controls When drawing sample rectangles in **Manual**, **Automatic**, or **Calibration** modes: ### Basic Controls - **Click and Drag:** Draw a sample rectangle - Red rectangle appears for Manual/Automatic modes - Blue rectangle appears for Calibration mode ### Advanced Controls - **Hold Spacebar while dragging:** Reposition the entire rectangle without changing its size - Keep mouse button held down - Press and hold Spacebar - Move the rectangle to a new location - Release Spacebar to continue resizing, or release mouse to finish - **Press Escape while dragging:** Cancel the current selection and start over - Rectangle disappears - Click and drag again to create a new selection These interactive controls make it easy to precisely position sample areas without having to redraw from scratch. --- ## Measurements Table All recorded measurements appear in the table with Lab values: - **L*** (Lightness): 0 (black) to 100 (white) - **a***: Green (negative) to Red (positive) - **b***: Blue (negative) to Yellow (positive) ### Saving Measurements Click **"Save Measurements"** to export your measurements as a text file. - The save dialog will pre-populate the filename with the name of your scanned image and the number of steps measured (e.g. `Q13-scan-001-SMT-21`). You can accept this name or type your own. - After the file is saved, you will be prompted: **"Open in Linearization Screen?"** - Click **Open** to immediately load the measurements into the single-channel linearization screen — no need to switch windows and re-open the file manually - Click **Cancel** to stay in the measurement tool --- ## Color Readouts Panel The live color readout panel displays current sample values in real-time: ### Displayed Values - **RGB values:** Red, Green, Blue (0.0 to 1.0 range) - **Lab values:** L* (Lightness), a* (green-red), b* (blue-yellow) - **Color swatch:** Visual preview of the sampled color ### Update Behavior - **Eyedropper mode:** Values update continuously as you move the cursor (live readout) - **Manual/Automatic mode:** Values update when you complete drawing a sample rectangle - **Calibration mode:** Values update when sampling reference patches The readout panel is particularly useful in Eyedropper mode, where you can explore the image and see Lab values in real-time without recording measurements. --- ## Best Practices ### Scanning Recommendations 23. **Scanner settings:** - Use highest available resolution (300-600 DPI minimum) - Disable all automatic color correction - Disable sharpening and dust removal - Use 16-bit color depth if available 24. **Target placement:** - Center the target on the scanner bed - Ensure the target is flat and not skewed - Use consistent lighting (built-in scanner lamp) 25. **File format:** - Save as TIFF or high-quality PNG - Avoid JPEG (compression artifacts affect measurements) ### Measurement Accuracy 26. **Sample area placement:** - Sample the center portion of each patch - Avoid patch edges (ink spread, cutting artifacts) - Use consistent sample area sizes 27. **Calibration:** - Always calibrate when measuring for profiling - Use a fresh, undamaged stepwedge for calibration - Recalibrate if scanning conditions change 28. **Verification:** - Use Eyedropper mode to spot-check automatic measurements - Compare measurements from the same target scanned multiple times - Known reference patches should read within ±1 L* unit after calibration --- ## Troubleshooting ### Measurements seem inaccurate - **Solution:** Perform scanner calibration using a grayscale stepwedge - Verify reference Lab L* values match your stepwedge specifications - Check scanner settings (no auto-corrections enabled) ### Colors look oversaturated after calibration - **Known issue:** The current calibration applies a Levels-style adjustment to all RGB channels equally - This is expected behavior and measurements remain accurate for Lab L* values - Future updates may include Luminosity blend mode ### Eyedropper values not updating - **Solution:** Ensure Eyedropper mode is selected from the Sample Mode dropdown - The cursor must be within the image bounds ### Can't reposition sample rectangle - **Solution:** Hold the Spacebar while dragging (not the Fn key) - This works while actively dragging the mouse (keep mouse button held) - Spacebar repositioning only works in Manual, Automatic, and Calibration modes - Not available in Eyedropper mode (which uses click-to-sample) ### Automatic mode measures wrong number of patches - **Solution:** Re-select Automatic mode from the dropdown to reopen the grid setup dialog and verify rows and columns - Ensure the drawn rectangle encompasses the entire target grid - The tool divides the rectangle evenly — partial patches at edges may cause issues ### Eyedropper mode doesn't work - **Solution:** Ensure Eyedropper is selected from the Sample Mode dropdown - Make sure the cursor is within the image bounds - The tracking area activates automatically when switching to Eyedropper mode ### Image appears skewed or at an angle - **Solution:** Use the **Perspective Correction** (de-skew) controls to straighten the image before measuring - Click each of the four corners of the target in the correct order (Top-Left → Top-Right → Bottom-Right → Bottom-Left) - Press Escape to cancel and start over if a corner was placed incorrectly --- ## Keyboard Shortcuts Reference ### Sample Drawing - `Spacebar` (hold while dragging) — Reposition sample rectangle - `Escape` (while dragging) — Cancel current selection ### Calibration - `Escape` (during calibration) — Cancel calibration workflow and reset ### Perspective Correction - `Escape` (during de-skew) — Cancel perspective correction and reset all corners --- ## Workflow Examples ### Example 1: Measuring a Q-13 Stepwedge for Profiling 1. Scan the Q-13 stepwedge at 300 DPI (no auto-corrections) 2. Load the scanned image into the tool 3. If the image is crooked, use **Perspective Correction** to straighten it before calibrating 4. **Start calibration** with default values (95.0, 50.0, 10.0) 5. Sample white, mid, and black patches using drawn rectangles - Use Spacebar to reposition rectangles if needed 6. Click **"Apply Calibration"** after sampling the black patch 7. Switch to **Automatic mode** from the Sample Mode dropdown 8. In the grid setup dialog, enter **1 row** and **21 columns** (for a full Q-13) 9. Draw a rectangle covering all 21 patches 10. Confirm automatic measurement 11. Click **"Save Measurements"** — accept the pre-filled filename or enter your own 12. Click **"Open"** in the follow-up prompt to load the measurements directly into the linearization screen ### Example 2: Spot-Checking Print Quality 13. Load your scanned print 14. (Optional) Calibrate if accurate measurements needed 15. Use **Eyedropper mode** (default mode) 16. Move cursor over areas of interest to see live Lab values 17. Click to record measurements of specific points 18. Compare Lab values against target values in the measurements table ### Example 3: Measuring an IT8 Target 19. Scan the IT8 target at highest resolution 20. Load and calibrate using the grayscale patches 21. Switch to **Automatic mode** 22. In the grid setup dialog, enter the IT8 grid dimensions (typically **12 rows × 22 columns**) 23. Draw a rectangle covering all color patches - Use Spacebar to reposition if the initial placement wasn't perfect 24. Confirm to measure all patches automatically 25. Review measurements in the table 26. Save and optionally open directly in the linearization screen ### Example 4: Using Eyedropper to Verify Calibration 27. After completing calibration, stay in **Eyedropper mode** 28. Move cursor over the white reference patch - Live readout should show L* ≈ 95.0 29. Move cursor over the mid patch - Live readout should show L* ≈ 50.0 30. Move cursor over the black patch - Live readout should show L* ≈ 10.0 31. If values are within ±1 L* unit, calibration is accurate --- ## Additional Notes - **Undo functionality:** Currently not available — use "Redo Sample" during calibration or redraw sample areas - **Multiple targets:** Close and reopen the tool for each new target - **Calibration persistence:** Calibration applies only to the current session — recalibrate each time you load a new image --- ## Support For questions, bug reports, or feature requests, please contact support or refer to the main QuadTone Profiler documentation. **Version:** 1.1 **Last Updated:** February 17 2026