What distinguishes Coloroid Pro from other camera filter apps?
Marina Ibrishimova: In addition to offering fun photo filters and mobile photo adjustment options, Coloroid Pro aspires to be a tool for artists, graphic designers, and architects, and anybody else who is interested in color harmony or how different people perceive the same colors differently.
Coloroid Pro’s harmonic filters attempt to harmonize the colors within an image, or more specifically, to force an image into one of several different harmonic schemes. Images that fit within a harmonic scheme are generally more visually appealing. Coloroid Pro also has accessibility filters that approximate what images look like to people with different types of color vision deficiencies.
What were some of the most surprising things you learned while developing a camera app?
MI: I was surprised to learn how hard color management is—no color ever looks exactly the same to anyone on any device!
I was also surprised to learn how easy it is to emulate effects that I thought were exclusively available for traditional film cameras. Coloroid Pro’s filter Infraredian emulates some of the effects typically seen in a developed Kodak HIE photograph, which are achieved as a result of the special properties of the physical film.
But most of all, I was surprised to learn the history of research on color harmony. Artists have been creating visually appealing masterpieces based on colors’ relative position to one another on the color wheel for centuries but it was surprising to find out that color harmony was also independently studied by mathematicians.Can you describe the relationship between mathematics and color harmony?
MI: Scientific research into color harmony dates back to one of the world’s most famous applied mathematicians, Isaac Newton, and to discoveries into the physical nature of light and color in general. Unfortunately, Newton alone was not able to describe color harmony mathematically. It took a few centuries and a brand new way of representing reality, namely digital imaging, for mathematicians to start looking at color harmony again in an attempt to describe it universally.
In particular, as developments in the digital representation of images emerged over the last century, efforts to describe color harmony were focused on categorizing visually appealing color schemes based on the colors’ relative positions to one another within a color space. Statistical analysis and various physiological studies helped shape the boundaries for visually appealing color schemes also known as harmonic templates.
Roughly speaking, most digital images today can be mathematically represented by a set of points, or pixels, where each pixel is represented by several integers. Typically, there are three integers each ranging from 0 to 255, and each representing one of three primary colors. (For example, the primary colors could be red, green, and blue, or some other primary colors depending on the color space; also a fourth integer may represent opacity, or a fourth primary color, and so on.)
Using algebra this representation of each pixel described by some primary color values can be “flattened” to reveal three separate channels: one for hue, one for saturation, and one for brightness of the pixel.
The algorithm currently used in Coloroid Pro for retrieving the hue of each pixel returns a floating point value in a range between 0 and 1 where the entire range represents all colors on the visible light spectrum that the average human can perceive (and mostly agree on) and smaller sections of the entire range represent individual hues.
Coloroid Pro’s color harmonization filter checks if a pixel’s hue value falls between a certain smaller predefined range within the spectrum to determine whether it fits into the chosen harmonic template and if it doesn’t, it converts this value to its complimentary value. For example, if a bad pixel’s hue value k is below 0.5 then its complimentary value becomes k + 0.5 or if k is above 0.5 then its complimentary value is k – 0.5.
This way of fitting an image within a color scheme by forcing the relative position of some of its pixels is the fastest way to harmonize an image that I can think of and it is the simplest way mathematically speaking but it is also the least subtle way and I’m currently working on making it better. Describing color harmony is still an open problem for both mathematicians and artists and there are no perfect solutions, but it is an exciting area of research.
What are your future hopes for Coloroid Pro, or camera apps in general?
MI: I hope to see Coloroid Pro become more useful. I will continue to improve the harmonic templates, and I hope to be able to collaborate with people from other disciplines who are interested in color harmony as well, whether they have some kind of an alternative color vision or not, in order to make a truly useful product for everyone.
More generally speaking, there are a lot of camera filter apps out there and all of them are great entertainment tools but I hope to see more camera apps solving big problems, even bigger than the one I’m trying to solve right now. For example, I hope to see a camera app that in addition to making your vacation photos brighter also warns you when you’ve had too much sun and helps you avoid a sun stroke. Or even a camera filter app that can identify early signs of certain diseases with pronounced physical symptoms. Of course, such developments also depend on developments in other fields, and on the collaboration of people across many disciplines in different parts of the world.