Question Answer
Why do I need D50 tubes? Color is Light, the color we see is influenced by the light source we view it under. For this reason, in order to create a level of standardization for critical appraisal of color, a standardized viewing condition was defined for the Graphic Arts Industry which includes print. This Standardized viewing condition is defined by the ISO specification ISO-3664:2009 in which the parameters of D50 compliance are well defined.
Can I buy any 5000K tube and will it be D50 compliant? No, 5000K refers only to the temperature of the light and is only one of several requirements in order for the light source to meet the specifications of D50.
My spectrophotometer has a D50 and a D65 setting, which one should I use? ISO 3664:2009 defines D50 as the standard viewing condition for the graphic arts industry. We should therefore also measure color and create ICC profiles etc. Using D50 illumination in our Spectral measurement devices. D65 which is also available on leading handheld spectrophotometers is used in industries where other standardized viewing conditions are defined such as paint and plastics.
What is Metamerism and why should I care about it? Metameric failure is when two samples match under one light source but not under another. In print this is particularly important when comparing an Inkjet proof to a printed press sheet. The pigments in inkjet inks and the production inks will fluoresce differently and at a different rate under different light. This takes us back to the need for standardized viewing conditions and standardized measurement conditions. The proofing system is calibrated with a Spectrophotometer to produce accurate color under D50 and well calibrated proof will match a D50 Printing condition under D50 light but under another light source they may look very different.
D50 Tubes that are ISO-3664:2009 compliant are really pricey, do I really need them? Setting up a standardized viewing environment is still the cheapest fix in color management and solves so many issues and questions. Many people today still rely solely on what they see in order to evaluate color, so standardized viewing conditions become critical in such cases. If you are still in doubt, contact us for your free GTI metamerism card and make a quick evaluation of your viewing conditions, at your press, QC area or boardroom.