HP Innovation Journal Issue 11: Winter 2018 | Page 56

DIVING DEEP IN COLOR SCIENCE Miguel A. Lopez-Alvarez, Ph.D. Color Scientist, Vancouver Imaging Team, HP EXPLORING THE WORLD OF COLOR SCIENCE When I chose color science as a field to start my doctorate work back in 2004, I didn’t expect I would get asked the same question so many times during the years to come: “What is it that you do as a color scientist?” Well, almost 15 years later, my answer to that question has evolved along with the evolu- tion of the technology in this specialized field. I have moved from saying that color science “helps understand how the human visual system processes light and color information” to “it’s a field of knowledge involving physics, optical engineer- ing, photonics, and psychology, that uses all kinds of tools and mathematical methods to make sure customers don’t com- plain about things like their printed photos not matching the real colors, or their just-repaired car door not being the same color as the bonnet.” On one occasion, “the question” landed me in a very fun situation. A TSA border control agent wanted to know why I was coming to be interviewed for an opening in color science. The more I talked about it, the more that agent was intrigued. Almost 30 minutes of friendly chitchat later, I ended up using her computer to explain why the colors on the display didn’t match the actual colors she was seeing from the security camera and how color science could solve that. Color science is basically about measuring colors as correctly as possible, and then using that information to manage how different devices (displays, printers, cameras, paint mixers, etc.) deal with color. It might sound simple, but it certainly starts to become complex as one dives deeper and deeper into the details. For example, have you ever wondered why the color of your car is so different at night under those yellow sodium lights in some parking lots? Or why the same lipstick color varies on different people depending on their skin tone or how white their teeth are? Or why the paint I chose at the store for my bedroom looks so different once I start painting with it? Why does a printed photo look so much brighter if I frame it with a black background instead of a white one? 54 HP Innovation Journal Issue 11 COLOR SCIENCE IN USE As a color scientist, I pay much attention to technological announcements where the terms “color management,” “color gamut,” or “color matching” are used. For me, it was inter- esting to see, for example, the increasing number of minutes used to describe the imaging details (including color) of the camera and display in every new iPhone’s keynote. The words “color gamut” or “color management” are now important fea- tures in mobile devices and software systems of all manufac- turers. People today care about the saturation of their mobile phone display and whether it is compliant with Adobe RGB or sRGB color spaces. All this is just slang for how many colors your display can show, how colorful it is and how accurately colors are represented in it—yet another set of numbers to add to device specs. For decades now, HP has been using color technologies in printing and imaging devices, making sure customers get the best-possible color out of their displays, printers, scanners and cameras. HP is a member of the International Color Consor- tium (ICC) (www.color.org), an organization “formed in 1993 in order to create an open, vendor-neutral color management system which would function transparently across all oper- ating systems and software packages.” The ICC standard for color profiles (a profile is a file describing the color attributes of a device) is widely used today, and it has enormously sim- plified—and improved—the way different devices need to transform color information to maintain a consistent appear- ance to customers. HP DesignJet printers, for instance, can print image files with embedded ICC profiles and deal inter- nally with all required transformations to make sure the color output of the print is as close as possible to what customers see on their displays. Similarly, customers who own a Sprocket printer are concerned about the color similitude between the sticky prints they obtain from their 2-by-3-inch printers, and how that photo looks on their mobile phone display. This com- parison can be made side by side, which makes color accuracy requirements very demanding. Another example is how HP will provide an accurate color preview in the coming “HP 3D SmartStream” software for color 3D printing on the HP Jet Fusion 300/500 series. HP is using top-notch color technolo- gies to achieve these goals and that makes the job of HP’s color scientists so interesting these days. If you have read all the way through here, then maybe I have convinced you to have a look at the Pantone coverage of the next printer you buy, or to double-check that your next phone display covers 100% of the sRGB gamut—or you will ask the photographer in your wedding to save all photos with an embed- ded Adobe RGB profile for better color saturation. If so, thanks for spreading the word. Color is important, after all.