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FAQ & Troubleshooting

This page addresses common user questions, issues, and best practices.

Common Issues​

1. I can’t see the annotated image after clicking “Calculate RF”​

  • Ensure both Min Line and Max Line are drawn
  • At least one spot must be marked
  • Click Calculate RF again and wait for image preview

2. RF values are missing or show zero​

  • Spot might be too close to the Min Line (baseline)
  • Lines may be placed in reverse order (Max below Min)
  • Click Reset and try again with better spacing

3. Upload to ELN does not work​

  • Upload works only if the image was loaded from Chemotion ELN
  • Ensure you are logged in to the ELN and CSRF token is available
  • Local uploads can’t be sent to ELN – only download is allowed

4. I see the message "No annotated image found"...​

  • You need to run RF calculation first

5. I see the message "Upload failed"...​

  • It means the CSRF token might got lost, try to refresh the page

Resetting​

Click the Reset button to:

  • Clear all annotations
  • Reset RF table and image
  • Start fresh with the same or new image

Pro Tips​

  • Always draw Min Line and Max Line before placing spots
  • Click the center of the spot on the TLC plate
  • Use a high-resolution image in bright light
  • Use the Reset button to correct mistakes

Valid RF Range Reference​

Spot PositionExpected RF ValueNotes
Near baseline~0.00–0.10Slow or large molecules
Middle of plate~0.40–0.60Good zone of separation
Near solvent front~0.80–0.99Highly mobile compounds
Below Min Line❌ InvalidSpot marked incorrectly

RF Value Warnings