1. How stable are the colors of ceramic tiles? High quality ceramic tiles are durable, stable, and cleanable. For more than 35 years metrologists and color scientists have universally adopted ceramic tiles for use as color standards.

2. How much does the color of a ceramic tile change in 1 year? With high quality tiles no measurable changes in color or appearance occur spontaneously.

3. How much does the color of a ceramic tile change in 5 years? No changes in color or appearance occur spontaneously, but ceramic glazes are subject to physical scratching and to etching following exposure to strong acids or alkalies. Such changes usually are not reversible. Consult our Maintenance Manual for more information.

4. Are any long-term color stability data available? Although our archives do not include this information, Dr. Art Springsteen (Avian Technologies L.L.C.) has re-calibrated individual sets of CERAM Series II tiles on an annual basis for more than 5 years. According to Dr. Springsteen no measurable changes in color or appearance occur provided that ceramic color standards are properly handled, maintained, and stored.

5. Are color standards affected by changes in ambient temperature? The color of a ceramic tile changes measurably and reversibly with changing temperature. During 2007 Dr. David Wyble (Munsell Color Science Laboratory, Rochester Institute of Technology) measured the "thermochromism" of our 3 standard tile sets. He concluded that thermochromism is comparable in our tiles and CERAM Series II tiles. This finding is not surprising since both sets of tiles are manufactured using standard commercial glazes and firing procedures. (Note: See FAQ 8.)

6. What can cause the color or appearance of a ceramic tile to change? If the tiles are handled or stored improperly, short-term, reversible color changes can occur. For example, if the user doesn't wear clean, lint-free gloves, tiles can become soiled in a single work session. If the optical surfaces are not damaged, soiling usually can be removed by careful cleaning. Ceramic glazes are subject to scratching and chemical etching. Tiles that have been damaged physically cannot be restored.

7. What materials and procedures should I use to clean the tiles? Consult our Maintenance Manual for this information.

8. What are the differences between CERAM tiles and Mt. Baker Research tiles? Because Ceram Technology Ltd. and the original manufacturers of our tiles use standard commercial glazes and firing procedures, the surface characteristics and many of the colors are similar. Our tiles are technically equivalent to CERAM tiles, although we offer many more colors than CERAM.

Our color standards offer the widest color gamut available in the international marketplace. The two photos that appear below show our reference collection of CERAM BCRA Series II tiles and CERAM Series II special chromatic and achromatic tiles. The areas of glare show that two edges of each CERAM tile exhibit curvature and pillowing (thickening of the glaze near the edges). The resulting deviations from flatness may lead to measurement errors. (Note: See FAQs 12 and 13 below.)

CERAM Series II tiles plus White & Black.

Special CERAM Chromatic & Achromatic tiles. (Bottom Row, CERAM White tiles.)

9. Do ceramic tiles exhibit surface defects? All ceramic glazes exhibit minor surface defects ("micropits") that are caused by out-gassing during kiln firing at high temperature. With high-quality tiles these defects do not interfere with color measurements.

10. Are Mt. Baker Research color standards flat? To eliminate edge defects and improve flatness we precision machine our standards from the flat central portions of nominal 6-inch ceramic plates. Unlike CERAM tiles, our standards do not exhibit curved edges or pillowing (thickening of the glaze near the edges). Therefore, our standards achieve effective optical contact with the full range of portable and benchtop spectrophotometers.

11. Why is surface flatness important? If the optical surface of a color standard is not perfectly flat (to within 0.001 inch), with many laboratory spectrophotometers the standard cannot contact the sample stage across the entire optical surface. This problem leads to measurable errors that vary from instrument to instrument depending on the design of the sample stage.

12. When is it necessary to calibrate individual tiles? Normal micropits and variations in glaze thickness and composition lead to measurable differences in color between individual tiles that are supposed to be identical. Individual calibration is the only way to correct for this problem.

13. How often should my color standards be calibrated? If ceramic tiles are handled and stored properly, spontaneous changes in color or appearance do not occur. We recommend annual re-calibration to users who are concerned about stability. Because our standards are inherently stable, these annual calibrations provide a check on the user's handling and storage procedures.

14. Where can I purchase certified, traceable calibration services? The staffs at Mt. Baker Research L.L.C. and Avian Technologies L.L.C. are trained and equipped to provide certified, traceable calibration services. Our abridged spectrophotometers are limited to the range 360 - 760 nm, and they output spectral reflectance factors at 10 nm intervals. Avian's dual-beam, scanning instruments can provide traceable reflectance and transmission measurements from the ultraviolet through the visible to the near-infrared with a measurement interval of 1 nm. Government-sponsored laboratories also offer certified calibration services, but they are more expensive. In North America contact the National Research Council, Canada, or the U.S. National Institute of Standards and Technology.

15. Can Mt. Baker Research produce custom tile shapes? On a special-order basis we can produce round ceramic color standards or geometric shapes with straight cut edges without sacrificing edge quality. If the best edge quality is not required, we can use less expensive cutting methods to manufacture standards of virtually any shape with maximum dimensions up to 6 inches.

16. Does Mt. Baker Research offer color standards with sealed edges? We are developing special holders and a mounting procedure that will use silicone resin to seal all 4 edges of our 2x2-inch square color standards.

17. Can Mt. Baker Research produce custom holders? We can manufacture custom holders in different sizes and with different size positioning wells. Custom holders may be subject to special pricing or a minimum order quantity. We provide the design work free, but complex designs may require an additional setup or "fixturing" charge at our machine shop.

18. How can I view the images on this Website with accurate color? All of our images are color-managed. To view them with accurate color you need to do two things: (1) Use a color-managed computer display. (2) Use color-management-savvy viewing software. On Apple Macintosh computers the Safari Web browser is color-managed, and Mac OS X automatically color-manages flat-panel displays. As another option, you can download the image files to your computer and view them on a color-managed display with Apple Previewer, Adobe Photoshop, or Photoshop Elements software. (Note: Microsoft software applications are not color-managed.)