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The Magical Tech Behind Paper For iPad's Color-Mixing

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Re: The Magical Tech Behind Paper For iPad's Color-Mixing

#11

Post by maggit »

leephillips wrote: post #3

This quote from the article: “Compare red nail polish to red ink: both are red, but the nail polish will be visible on black paper because it reflects light. The ink won’t be, because it absorbs light.” doesn't seem right to me, but I'm not an expert. The ink doesn't reflect light? If you put a drop of red ink on a sheet of glass, it won't look red? Isn't the difference because the ink will soak in to the paper while…

The nail polish is opaque, which means it reflects or absorbs light that hits it. Red nail polish reflects red light and absorbs the rest. Shine white light on it, and it will look red.

Ink is transparent; It lets through or absorbs light that hits it. Red ink lets though red light and absorbs the rest. Shine white light through it, and it will look red.

Shining white light on a black piece of paper with red ink on it will look black. What light is not absorbed by the ink is absorbed instead by the paper.

Of course red ink reflects light, as you say, but that is just because of reality. It is not essential to its function. If it were possible to make a 100% non-reflective ink, it would work perfectly well.

I hope this clears it up :)

Re: The Magical Tech Behind Paper For iPad's Color-Mixing

#12

Post by glhaynes »

alayne wrote: post #9
stevenwei wrote: post #6

Make no mistake, this level of attention to detail is why this app has remained consistently in the top charts since its release.

It's on the charts because it's "free". The overall rating is only 4/5 stars on itunes. They use the annoying model of making you buy tools like color as in app purchases. Notability, which has some similarities, sells for 0.99 without in app purchase nonsense and is rated higher.

I don't get the hate for in-app purchases of this kind. It's just like the shareware model that used to be popular: lots of people get absolutely free usage/enjoyment out of the base product and then, those who specifically want more, can pay—in this case a very small fee—for it. One constantly hears people clamoring for more choice, for example, to pay for just the cable channels they want. So what makes this model "annoying nonsense"?

Re: The Magical Tech Behind Paper For iPad's Color-Mixing

#14

Post by gmaslov »

I was disappointed to read that they gave up the principled modeling approach (the 80-year old German paper mentioned early on in the article) and instead collected 100 data points that "looked good" and interpolated somehow.

The article says that the Kubelka-Munk model achieved color mixing that was "too realistic" and therefore difficult to use for the purpose of creating a distinctive brand palette. What this tells me is that they weren't looking for a model of how colors mix together, but a model of what colors look good together.

> "We know red and yellow should yield orange, or that red and blue should make purple--but there isn't any way to arrive at these colors no matter what color-space you use."

Well, that's clearly not true. In the HSL color wheel [1], orange is halfway between red and yellow, and purple is halfway between red and blue. Should have picked a better example.

[1] http://www.workwithcolor.com/hsl-color-picker-01.htm

Re: The Magical Tech Behind Paper For iPad's Color-Mixing

#15

Post by sp332 »

aw3c2 wrote: post #5
0x0 wrote: post #2

I wonder if CMYK would be appropriate? The article didn't mention anything about it (even though it talks about how they tried a bunch of other color spaces by name)

CMYK is an subtractive color model, it is not very understandable and definitely not intuitive for human color perception. HSL is much better for that. It all is not too revelant in the end result I think because those are just models and their software exposes certain aspects of colors.

Mixing pigments (ink or paint) can be done in CMYK because it is a subtractive process. It would have been realistic and something that anyone who has played with finger paints or crayons has experienced. (Although I agree that it's not very relevant to the end result, it would have been nice to see it in the discussion.)

Re: The Magical Tech Behind Paper For iPad's Color-Mixing

#16

Post by arscan »

leephillips wrote: post #3

This quote from the article: “Compare red nail polish to red ink: both are red, but the nail polish will be visible on black paper because it reflects light. The ink won’t be, because it absorbs light.” doesn't seem right to me, but I'm not an expert. The ink doesn't reflect light? If you put a drop of red ink on a sheet of glass, it won't look red? Isn't the difference because the ink will soak in to the paper while…

It won't look red if you put that sheet of glass over a black piece of paper.

Ink is semi-transparent. So think of white paper as a light source, and the red ink absorbs all colors but red coming off the paper before it reaches your eye.

Nail polish isn't transparent, but it still looks red because it simply reflects red light. That light never reaches the paper -- it bounces off the nail polish and comes back to your eye.

Re: The Magical Tech Behind Paper For iPad's Color-Mixing

#18

Post by kenperkins »

glhaynes wrote: post #12
alayne wrote: post #9

Earlier quoted context omitted.

It's on the charts because it's "free". The overall rating is only 4/5 stars on itunes. They use the annoying model of making you buy tools like color as in app purchases. Notability, which has some similarities, sells for 0.99 without in app purchase nonsense and is rated higher.

I don't get the hate for in-app purchases of this kind. It's just like the shareware model that used to be popular: lots of people get absolutely free usage/enjoyment out of the base product and then, those who specifically want more, can pay—in this case a very small fee—for it. One constantly hears people clamoring for more choice, for example, to pay for just the cable channels they want. So what makes this model…

I think because some class of people wonder if a $5 app would better perform. I think it's hard for 53 to succeed that way however, because you have a finite number of users.

By making features an in-app purchase, they effectively monetize users going from version 1 to version 2, and so on. If you used the up-front payment model, new versions of the app would have to be a different app to continually monetize it, which would have a number of it's own problems.

Re: The Magical Tech Behind Paper For iPad's Color-Mixing

#19

Post by julianwa »

gmaslov wrote: post #14

I was disappointed to read that they gave up the principled modeling approach (the 80-year old German paper mentioned early on in the article) and instead collected 100 data points that "looked good" and interpolated somehow. The article says that the Kubelka-Munk model achieved color mixing that was "too realistic" and therefore difficult to use for the purpose of creating a distinctive brand palette. What this tell…

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.

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