Slide micrometers and calibration slides for accurate measurement

Our slide micrometers and calibration slide range.

We stock a range of high quality, precision slides with reflective markings. This makes them suitable for use with all microscopes that use transmitted, reflected or oblique illumination.

Our multi-scale calibration slide is the best option for most applications.

We have some notes on use below and a video example of calibrating Mosaic 2.0 software.

Notes on using calibration slides

  • Make sure that you are familiar with the calibration process in your software. The steps will be different, but the process is the same.
  • You will need to make a new calibration for each objective, camera and c-mount adaptor combination.
  • Anything that changes the total magnification will affect the accuracy. If you change the c-mount focus, you should check your calibration remains accurate.
  • The software generally only measures the actual number of pixels in the line. It will then calculate the measurement based on the calibration or measurement level that you have selected. This is a feature but may feel wrong at first.
  • Make a note of your units, and that you know to convert between the units the slide is in and the units you report in.
  • Make a note of the “pixels per unit” or similar for each objective. While this is unique for each set-up, it will quickly let you note any changes made by another operator.
  • Have a reference sample handy too. Use something that you have a good idea of the actual measurements.
  • When measuring, use the same edge for both the starting and ending points of your calibration line.
  • Use the minor divisions to make as close to a straight or 90° line as possible. This will minimise parallax error, although this will be very small.

Quick reference for unit conversion

mm Microns (μm) nm Reference
1.00 1,000 1,000,000 Head of a pin (1mm)
0.10 100 100,000 Human hair (100μm)
0.01 10 10,000 Fungal hyphae, cotton fibre (10μm)
0.001 1 1,000 spider web silk (3–8μm)
0.0001 0.1 100 largest sized particle admitted through surgical mask, 90% of wood smoke is smaller than this.
0.00001 0.01 10 Smallest sized tobacco smoke particle
0.000001 0.001 1 Length of sucrose molecule, diameter of carbon nano-tube

Other units

mm Factor Unit
1 0.039 Inches
1 10,000,000 ångström

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