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The Gerber Viewer (GerbView) is a specialized tool for viewing and analyzing Gerber files and drill data used in PCB manufacturing.

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Overview

GerbView allows you to:
  • View Gerber RS-274X and X2 files
  • Inspect Excellon drill files
  • Verify manufacturing outputs before production
  • Compare layers for alignment
  • Measure features and clearances
  • Export to PCB format

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Supported File Formats

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Gerber Files

RS-274X

Standard Gerber format:
  • Aperture definitions
  • Draw and flash commands
  • Most common format
  • Widely supported

Gerber X2

Extended format with attributes:
  • Metadata embedded
  • Layer function info
  • Component outlines
  • Better for CAM software

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Drill Files

Standard NC drill format:
  • Tool definitions
  • Drill coordinates
  • Plated/non-plated holes
  • Common in industry
Project metadata (.gbrjob):
  • Lists all Gerber files
  • Layer stackup
  • Board outline
  • Manufacturing notes

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Interface Layout

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Layer Management

Left Panel - Layers Manager:
  • Graphic Layers: 32 available layers
  • Layer assignment: Map Gerber files to layers
  • Visibility control: Show/hide individual layers
  • Color selection: Customize layer colors
  • Transparency: Adjust layer opacity
GerbView has 32 graphic layers available, more than enough for complex boards

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Main Canvas

Rendering Options:
  • Normal: All visible layers shown
  • Negative objects: Show clearances
  • DCodes: Display aperture codes
  • High contrast: Highlight active layer

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Loading Files

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Opening Gerber Files

1

Single File

File → Open Gerber File(s) or Ctrl+O
  • Browse to .gbr, .pho, or similar
  • File loads to next available layer
2

Multiple Files

Select multiple files in dialog
  • Files load to sequential layers
  • Or drag and drop files onto window
3

Job File

File → Open Gerber Job File
  • Loads entire project at once
  • Proper layer assignment
  • Includes stackup info
4

ZIP Archive

File → Open ZIP Archive
  • Extract and load all Gerbers
  • Convenient for fab house files

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Loading Drill Files

File → Open Excellon Drill File(s):
  • .drl, .txt, .nc extensions
  • Auto-detected or manually specified
  • Shows plated and non-plated holes
  • Can overlay on copper layers

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Layer Assignment

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Typical Layer Mapping

Layer 1: F.Cu (Front Copper)
Layer 2: B.Cu (Back Copper)
Layer 3: F.Paste (Front Solder Paste)
Layer 4: B.Paste (Back Solder Paste)
Layer 5: F.Silks (Front Silkscreen)
Layer 6: B.Silks (Back Silkscreen)
Layer 7: F.Mask (Front Soldermask)
Layer 8: B.Mask (Back Soldermask)
Layer 9: Edge.Cuts (Board Outline)
Layer 10: Drill File (PTH)
Layer 11: Drill File (NPTH)

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Color Coding

Use standard PCB colors for realistic preview:
  • Copper: Orange/copper
  • Soldermask: Green (or fab house color)
  • Silkscreen: White
  • Paste: Gray/yellow
  • Drill: Black or white

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Inspection Tools

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Measurement Tool

Tools → Measure or Ctrl+Shift+M:

Distance

Measure between two points:
  • Click start point
  • Click end point
  • Shows X, Y, and total distance

Features

Inspect dimensions:
  • Pad sizes
  • Track widths
  • Clearances
  • Hole diameters

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D-Code Display

D-codes define aperture shapes and sizes used in Gerber files
View D-Codes:
  • View → Show DCodes: Toggle aperture numbers
  • Useful for verifying pad sizes
  • Check if apertures match expectations

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Transparency Control

1

Adjust Layer Opacity

Use slider in Layers Manager
2

See Through Layers

View multiple layers simultaneously
3

Check Alignment

Verify registration between layers

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Verification Workflow

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Pre-Production Checklist

✅ Correct number of copper layers ✅ All technical layers present ✅ No missing files
✅ Layers align correctly ✅ Drill holes on pads ✅ Soldermask over copper ✅ Silkscreen clear of pads
✅ Edge cuts layer present ✅ Closed outline polygon ✅ No gaps or overlaps ✅ Correct board dimensions
✅ PTH (Plated Through Hole) file ✅ NPTH (Non-Plated) file if needed ✅ Holes sized correctly ✅ Via and pad drills proper
✅ Copper to edge clearance ✅ Trace spacing adequate ✅ Soldermask expansion correct ✅ No silkscreen on pads

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Common Issues to Check

Missing Layers: Ensure all required Gerber files are loaded
Misaligned Layers: Check for offset between copper and mask layers
Polarity Errors: Verify dark vs clear layer polarity
Aperture Sizes: Confirm pad and trace dimensions

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Export and Conversion

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Export to PCB Format

Convert Gerber files back to KiCad PCB format
File → Export to PCBNew:
  1. Load all Gerber layers
  2. Assign layers correctly
  3. Export to .kicad_pcb format
  4. Open in PCB Editor
Conversion is not perfect - use for reference or reverse engineering only

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Print/Plot

File → Print:
  • Generate PDF of Gerber layers
  • Create assembly drawings
  • Documentation for manufacturing
  • Single or multiple layers

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Layer Manager Features

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Layer Controls

  • Eye icon: Show/hide layer
  • Color swatch: Change layer color
  • Opacity slider: Adjust transparency
  • Negative checkbox: Invert polarity

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Toolbar Functions

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Top Toolbar

IconFunctionShortcut
OpenLoad Gerber fileCtrl+O
ReloadRefresh filesF5
PrintGenerate PDFCtrl+P
Zoom In/OutAdjust view+/-
Zoom FitFit boardHome
MeasureDistance toolCtrl+Shift+M

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Auxiliary Toolbar

Display Options:
  • Active layer selector
  • Grid settings
  • Units (mm/inch/mils)
  • Cursor coordinates
  • Measurement mode

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Comparison with PCB

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Gerber vs PCB Verification

1

Open Both

  • PCB in PCB Editor
  • Gerbers in GerbView
2

Visual Compare

Side-by-side comparison:
  • Layer registration
  • Feature alignment
  • Dimension verification
3

Check Differences

Look for:
  • Missing features
  • Size discrepancies
  • Position errors

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Advanced Features

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Gerber Attributes

X2 format includes embedded metadata
Attribute Display:
  • File function (copper, mask, etc.)
  • Layer side (top/bottom)
  • Component outlines
  • Manufacturing notes

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Differential Pair Inspection

Verify high-speed traces:
  • Load differential pair layers
  • Measure spacing
  • Check length matching
  • Verify impedance zones

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Multi-Board Panels

Inspect panelized boards:
  • View full panel layout
  • Check fiducial markers
  • Verify breakaway tabs
  • Measure panel dimensions

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Keyboard Shortcuts

ActionShortcut
Open GerberCtrl+O
Open DrillCtrl+D
Reload AllF5
Zoom In+ / F1
Zoom Out- / F2
Zoom FitHome / F4
MeasureCtrl+Shift+M
Grid NextN
Units ToggleU
High ContrastH
Flip BoardF

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Tips and Best Practices

Always verify Gerber files before sending to manufacturer
Use Job Files for automatic correct layer loading
Check Alignment by toggling layer visibility
Verify Drills are centered on pads
Polarity: Ensure positive/negative layers are correct

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Troubleshooting

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File Won’t Load

  • Not a valid Gerber/Excellon file
  • Use text editor to verify file header
  • Check for Gerber RS-274X format codes
  • File uses incorrect character encoding
  • Try opening in text editor and re-saving as UTF-8
  • Re-export from PCB Editor
  • Verify file size isn’t zero

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Display Problems

If layers appear blank, check:
  • Layer visibility enabled
  • Zoom level appropriate
  • Polarity setting correct

PCB Editor

Generate Gerber files

Manufacturing Output

Learn Gerber export process and send files to fab house

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