To provide accurate data, your spectrophotometer needs to be well-maintained. This includes calibrating it daily, at the start of a shift, or before beginning any important measurement job. Calibration is important both for color measurement and to maximize inter-instrument agreement.
Here’s what you need to know about calibration tiles.
The different colors of calibration tiles
Absolute black is measured using a “zero reflectance” or “black trap” attachment that absorbs all light. For white, the readings of a particular, serialized reference tile are stored in each instrument. Both the tile and trap need to be scrupulously clean to avoid false readings and to also protect the spectrophotometer and subsequent samples from contamination.
In addition to black and white, blue or green tiles are commonly used as diagnostic references.
To keep your color measurements as accurate as possible, calibration tiles need special attention. Here are some guidelines.
How to store and handle tiles
- Store tiles in a protective case
- Store tiles away from sunlight or other sources of ultraviolet radiation
- Hold a tile by the edges of its holder to avoid surface contamination
- Hold the tile only briefly to avoid temperature changes
How to use tiles
- Only use the white calibration tile associated with the instrument
- Place the tile gently against the instrument port
- Position the tile consistently relative to the port for each measurement
- Make measurements promptly
- After use, remove the tile without sliding or rotating it against the aperture plate, to avoid abrasion
- Do not use the white tile for any other purpose
How to clean tiles
- Gently breathe on the tile before use and wipe with a soft, lint-free cloth
- Wash only if necessary to remove fingerprints or debris
- Use a diluted detergent solution free from brighteners or dyes
- Use only a few drops of solution to moisten a soft, lint-free cloth
- Clear away the solution with clean water and gently wipe dry before use. Do NOT submerge the tile under water. This will destroy the tile
- Use alcohol wipes to clean inks, paints, or other coatings
- Gently wipe surface to soften residue, avoiding abrasion
- Repeat if necessary
- Follow by washing with detergent
- Never immerse tiles in any fluid
- Never use abrasive cleaners or metal objects to remove dirt
Even a small amount of dirt, oil, or abrasion on the surface of a tile will affect measurement accuracy. Handle tiles with utmost care and replace them if they become damaged in any way.
If you ever have questions about using or caring for your equipment, our support team can help. Find your local team here.
Want more advice on getting accurate measurements? Next, read our blog on four environmental factors you should avoid when performing color measurements.