The Core Concepts: DPI vs. LPI vs. Interval
DPI (Dots Per Inch) & LPI (Lines Per Inch) measure density—how many lines fit in an inch. Line Interval measures distance—the physical gap between lines in millimeters. In DithX you can set these to match your laser and material.
In laser engraving, they are mathematically locked: high DPI = small Interval.
The Math & Conversion
Use this formula to convert between density and distance:
Interval (mm) = 25.4 ÷ DPI
127 DPI = 0.200mm
254 DPI = 0.100mm
318 DPI = 0.080mm
423 DPI =
0.060mm
The Golden Rule: Spot Size
Your ideal Line Interval should match your laser's focused Spot Size.
- ⚠ Interval > Spot: Gaps appear (Banding).
- ⚠ Interval < Spot: Overlap (Overburn/Blur).
- ✓ Interval = Spot: Perfect sharpness.
Material Reference Cheat Sheet
Wood
Avoid
overburn
254 - 318 DPI
(0.08 - 0.10mm)
Slate
High
contrast
318 - 423 DPI
(0.06 - 0.08mm)
Glass / Acrylic
Detail
focused
318 - 600 DPI
(0.04 - 0.08mm)
Coated Metal
Sharp
removal
318 - 423 DPI
(0.06 - 0.08mm)