julianwa

Disclaimer: Co-founder of FiftyThree

Please see my response here: https://news.ycombinator.com/item?id=7181910

Disclaimer: I'm a co-founder at FiftyThree

Just a few facts:

1. "Paper", an app from developer "Contradictory", has existed in the App Store since October 27, 2011. This is presumably before miSoft registered their Paper. (https://twitter.com/FiftyThree/status/430873195097632769) Contradictory is clearly a name squatter.

2. miSoft's Paper launched ~5 months after Paper by FiftyThree. (https://twitter.com/FiftyThree/status/430845528805756928)

3. miSoft renamed another of their apps "Kid Paint" to "Paper Express" on 12/20/2012 after FiftyThree won App of the Year (https://twitter.com/georgpetschnigg/status/43091631900616704...)

Krita has (or had) an interesting implementation for paint mixing that uses Kubelka-Munk: http://www.youtube.com/watch?v=lyLPZDVdQiQ

You're correct in that, for example, purple lies halfway between read an blue in terms of hue. However, an interpolation between those colors based on hue that does not adjust saturation, will look quite ugly, as it passes through magenta, etc. The question is, how should one adjust the saturation?

There's nothing wrong with any given color space. It was designed with particular goals in mind, and those goals generally did not include attractive blending through linear interpolation. So, yes, we developed a means of hand-tuning the interpolation such that it produces colors that look good together, which is what our users really cares about.

Kubelka-Munk is fantastic for modeling the behavior of real world pigments as they're applied in thin layers on a canvas. However, since we were not trying to simulate the act of using physical watercolor, oil paints, etc., it was not only overkill but actually produced unintuitive results.

Our problem is more abstract. We want to appeal to the user's notions of how pigments blend together, but in such a way that the operation is predictable and can be hand tuned to avoid unpleasant cases. Ultimately, the mixing behavior that we released is inspired by the physical world, but is tuned by our designers to produce what they consider pleasing results.

FiftyThree (New York, NY and Seattle, WA) - creators of Paper for iPad

At FiftyThree we build tools for mobile creation. Two months ago, we launched Paper , the simplest and most beautiful way to create on the iPad. Within two weeks, Paper was downloaded 1.5 million times and used to generate over 7 million creations.

http://www.fiftythree.com

Our ambition is no less than to change the way people create, and we're just getting started. We're building world-class engineering teams in NYC and Seattle — spanning hardware, software, and services — to take on this challenge.

http://www.fiftythree.com/jobs

We look forward to hearing from you!

It sounds as if you're rotating one finger around the other? The idea is to use two fingers together (like one big finger) to do a pan in a circular motion.