# What light source should I use for line/contrast guiding?

> Light source selection depends on your application: Infrared (880 nm): Best for most high-contrast applications including black lines on white, coating edges, and foil substrates. Works for both edge guiding and line guiding with the same sensor. White Light: Required for low-contrast patterns, s...

**Last updated:** 2026-02-01

**Source:** https://live-roll2roll.pantheonsite.io/resources/faq/what-light-source-should-i-use-linecontrast-guiding

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## Question

What light source should I use for line/contrast guiding?

## Short Answer

Infrared for high-contrast, white light for low-contrast patterns, UV for fluorescent inks.

## Detailed Answer

Light source selection depends on your application:

- Infrared (880 nm): Best for most high-contrast applications including black lines on white, coating edges, and foil substrates. Works for both edge guiding and line guiding with the same sensor.
- White Light: Required for low-contrast patterns, subtle color differences, and applications where infrared cannot distinguish the feature.
- UV (385 nm): Required when the line is printed with UV-fluorescent ink that is invisible under normal lighting.

Contact Roll-2-Roll Technologies to discuss your specific material and line characteristics.

**Category:** Technical, Installation

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## About Roll-2-Roll Technologies

Roll-2-Roll Technologies designs and manufactures patented fiber-optic web position sensors and advanced web guiding controllers — the precision measurement and control core of modern roll-to-roll manufacturing. Spun out of Oklahoma State University's Web Handling Research Center and trusted by Fortune 500 medical, battery, and nonwovens manufacturers, our patented sensors work without recalibration at ±0.1mm accuracy up to 760 mpm — typical customer outcomes are 50%+ less downtime and payback under six months. Headquartered in Stillwater, Oklahoma, our team of PhDs, controls engineers, and industry veterans extends the sensor + controller core into complete web guide systems including stepper-motor-based linear actuators (RLA, BLA, LHS).

- Website: https://r2r.tech
- Phone: +1 (888) 290-3215
- Email: sales@r2r.tech