[jeresig]

One thing I should note is that when looking at prints (at least for when it comes to technical analysis) being able to see accurate representations of the lines is far more important than the uniformity of colored regions. Color is almost always at the whim of the printer on any given day, whereas the black lines (from the keyblock) should always remain the same. Granted you're going to have issues either way (using this tool or doing normal scaling) as the source material is inherently compromised.

Although it's not clear what scenes exactly the upscaler was trained up, I suspect that it's currently best suited towards scenes that have lots of large bold lines and not lots of tiny details.

[Nadya]

I imagine it was trained on 'typical' anime-style art of black/bold character outlines and mostly flat colors.

A common solution to resizing anime characters is to create a colored vector of an image. The differences between these vectors and the original stills are minimal and usually 'satisfactory'. There is an entire scene of people who create these vectors and another scene of people who use the vectors to create wallpapers and other graphics. [0] Waifu2x can help replace the need to vector these images by increasing the quality of upscaling them.

This is the prevalent 'style' for anime - at least from the past 8-10 years or so. There are a few outliers and I imagine Waifu2x would work poorly on them. For example, I do not see it working well on a still from "The Garden of Words". [1]

[0] http://img04.deviantart.net/96b1/i/2015/105/8/d/oumae_kumiko...

[1] https://24framesps.files.wordpress.com/2014/11/the-garden-of...

[raverbashing]

One potential point of improvement is training the neural network in prints with Japanese text, this seems to be the weakest point in using the Anime trained one.

[wavefunction]

cheers for everything, and this comment