I found the best scientific explanation of the white gold vs blue black dress debate which has been raging on social media on the Wired Magazine site. It mainly has to do with the context and adjustments your eyes make. This is just an extreme case where it falls right on the boundary of interpretation.

If you really want to have your eyes crossed and rolled back in your head I suggest you look up the wikipedia article on metamerism.

The article specifically mentions a whole host of reasons that colors don’t look alike such as lighting, dyes, fluorescents, different types of inks, varieties of fabrics and on and on. These are unfortunately all things we deal with all day every day as decorators.

I have written on this subject before and it gets extremely complicated. Rather than get into it right now, I’ll just go straight to some solutions. On social media the color of the dress debate is fun, but when a customer thinks they are getting one color of ink or shirt and you give them something else it is no longer fun and potentially a very expensive debate.

– light boxes, spectrometers etc are nice scientific tools, but they are not practical. We sell shirts and print and embroider in the real world not in a laboratory. You may find some of that stuff helpful, but it will not save you or even give you definitive answers on color.

– look at everything in fluorescent light, sunlight and in-between if you can.

– don’t trust color photos or color monitors. In particular prints usually look better in a photo.

– do use pantone books to communicate  about colors and make sure they don’t get faded. Don’t trust looking at Pantone on any color monitors.

– look at colors in a neutral area, background color actually physically affects your eyes and can cause you to see the color differently.

– on big projects either get the customer to pay, or pay for it yourself, or split it, but make sure the customer signs off on a sample print and shirt, particularly when you have sensitive colors like Coke red, Pepsi blue, or colors people don’t agree on (I dare you to find ten people to agree on what color is maroon…)

– clearly mark in some permanent fashion the approved sample from the customer. Signing it in permanent marker is a good method.

– look with the customer at samples in different light together when necessary to show what is going on. We once had a “natural” colored shirt we made “natural” tags for. In sunlight they were a perfect match, in fluorescent lighting of the customer’s warehouse they basically looked like white tags on a brown shirt…

– we send out lots of real shirts to customers, it is money well spent and our vendors help us out or they aren’t our vendors any more. Photos on line or on paper don’t cut it. Even small swatches in a book don’t cut it. Take a look at a Next Level “indigo” shirt. I have had that called green, blue, blue green, grey green….  A customer wanting one has to see a real shirt. And to further complicate it, a cotton and a poly-cotton don’t look at all alike!

I’ll end with the wiki article on metamerism, and it will mainly tell you that this should tell you that it is freakin’ complicated and you have to find ways to work it out:

Sources of metamerism

Metameric matches are quite common, especially in near neutral (grayed or whitish colors) or dark colors. As colors become brighter or more saturated, the range of possible metameric matches (different combinations of light wavelengths) becomes smaller, especially in surface colors.

Metameric matches made between two light sources provide the trichromatic basis of colorimitry. For any given light stimulus, regardless of the form of its spectral emittance curve, there always exists a unique mixture of three “primary” lights that when added together, or added to the stimulus, will be an exact metameric match.

The basis for nearly all commercially available color image reproduction processes such as photography, television, printing, and digital imaging, is the ability to make metameric color matches.

Making metameric matches using reflective materials is more complex. The appearance of surface colors is defined by the product of the spectral reflectance curve of the material and the spectral emittance curve of the light source shining on it. As a result, the color of surfaces depends on the light source used to illuminate them.

Metameric failure

The term illuminant metameric failure is sometimes used to describe situations where two material samples match when viewed under one light source but not another. Most types of fluorescent lights produce an irregular or peaky spectral emittance curve, so that two materials under fluorescent light might not match, even though they are a metameric match to an incandescent “white” light source with a nearly flat or smooth emittance curve. Material colors that match under one source will often appear different under the other.

Normally, material attributes such as translucency, gloss or surface texture are not considered in color matching. However geometric metameric failure can occur when two samples match when viewed from one angle, but then fail to match when viewed from a different angle. A common example is the color variation that appears in pearlescent automobile finishes or “metallic” paper; e.g., Kodak Endura Metallic, Fujicolor Crystal Archive Digital Pearl.

Observer metameric failure can occur because of differences in color vision between observers. The common source of observer metameric failure is colorblindness, but it is also not uncommon among “normal” observers. In all cases, the proportion of long-wavelength-sensitive cones to medium-wavelength-sensitive cones in the retina, the profile of light sensitivity in each type of cone, and the amount of yellowing in the lens and macular pigment of the eye, differs from one person to the next. This alters the relative importance of different wavelengths in a spectral power distribution to each observer’s color perception. As a result, two spectrally dissimilar lights or surfaces may produce a color match for one observer but fail to match when viewed by a second observer.

Finally, field-size metameric failure occurs because the relative proportions of the three cone types in the retina vary from the center of the visual field to the periphery, so that colors that match when viewed as very small, centrally fixated areas may appear different when presented as large color areas. In many industrial applications, large field color matches are used to define color tolerances.

The difference in the spectral compositions of two metameric stimuli is often referred to as the degree of metamerism. The sensitivity of a metameric match to any changes in the spectral elements that form the colors depend on the degree of metamerism. Two stimuli with a high degree of metamerism are likely to be very sensitive to any changes in the illuminant, material composition, observer, field of view, and so on.

The word metamerism is often incorrectly used to indicate a metameric failure rather than a match, or incorrectly used to describe a situation in which a metameric match is easily degraded by a slight change in conditions, such as a change in the illuminant.

Measuring metamerism

The best-known measure of metamerism is the color rendering index (CRI), which is a linear function of the mean Euclidean distance between the test and reference spectral reflectance vectors in the CIE 1964 color space. A newer measure, for daylight simulators, is the MI, CIE Metamerism Index^[1] which is derived by calculating the mean color difference of eight metamers (five in thevisible spectrum and three in the ultraviolet range) in CIELAB or CIELUV. The salient difference between CRI and MI is the color space used to calculate the color difference, the one used in CRI being obsolete and not perceptually uniform.

MI can be decomposed into MI_vis and MI_UV if only part of the spectrum is being considered. The numerical result can be interpreted by rounding into one of five letter categories:^[2]

Metamerism and industry

Using materials that are metameric color matches rather than spectral color matches is a significant problem in industries where color matching or color tolerances are important. A classic example is in automobiles: the interior fabrics, plastics and paints may be manufactured to provide a good color match under a standard light source (such as the sun), but the matches can disappear under different light sources (fluorescent or halide lights). Similar problems can occur in apparel manufactured from different types of dye or using different types of fabric, or in quality color printing using different types of inks. Papers manufactured with optical brighteners are especially susceptible to color changes when lights differ in their short wavelength radiation, which can cause some papers to fluoresce.

Color matches made in the paint industry are often aimed at achieving a spectral color match rather than just a tristimulus (metameric) color match under a given spectrum of light. A spectral color match attempts to give two colors the same spectral reflectance characteristic, making them a good metameric match with a low degree of metamerism, and thereby reducing the sensitivity of the resulting color match to changes in illuminant, or differences between observers.