I'm a developer who wants to figure out when a filter would look good applied to a given image.

For example, I have sepia, solarisation and pencil filters.

Okay, the perception will be very different from person to person, but maybe there is some scientific evidence or grounds upon which to decide which effects would look good if there is a special color(range), contrast or object in my picture. (Object recognition is very ugly in a computer-vision-process. There are only good general solutions to detect architecture or faces.)

For example, I could use a Sepia filter to make a dramatic scene of a dark, cloudy sky, or make skin more attractive. Is there a general set of image characteristics that can be used as a guideline for selecting filter effects?

What I mean is, how can I decide to apply filters automatically/programmatically?

  • 2
    This might help you - photo.stackexchange.com/questions/2325/…
    – dpollitt
    Jul 30, 2012 at 20:24
  • @DarkcatStudios: Please be cordial...no need to be rude, not everyone who visits this site is a fully fluent in English grammar, is familiar with the nuances of American conversation, nor necessarily an adult. Please take these things into consideration when commenting. If the fundamental intent of a question is clear, you can always edit to improve grammar and spelling.
    – jrista
    Aug 1, 2012 at 7:31

2 Answers 2


This is a lot more difficult than it may seem at first glance (even if you assume that it will be very difficult). Let's start by looking at the two example pictures you have linked in the question.

In the first picture, the decision to transform the existing sky, and only the sky, of a colour photograph into an "Ansel Adams in Yosemite" study in high-contrast black and white is a completely non-standard and non-obvious artistic decision. The resulting sky is deeply rooted in the photographic vocabulary of another era, and can be evocative of many things, but unless you are trying to touch those implied elements, whether that be summoning the ghosts of a wilder, freer time and pace, or even merely "of course I've heard of Ansel Adams, idiot!", then it's not the sort of thing you'd want to do to your photo in the average case. You'd be much more likely to try to retroactively apply graduated neutral density and polarizing filters, leaving the image in colour. The decision to use a warm-toned treatment (it is most assuredly not a sepia effect) of the black and white sky, however, follows much more logically, since a purely neutral greyscale or a cold-toned treatment would not blend nearly as well with the rest of the image, and would have a more jarring cut-out effect—but you'd have to come up with the black-and-white idea first, and that's just weird.

As for the second picture, I can think of a half-dozen different treatments I might give it as a made-for-the-purpose commercial shot (is it for hair styling? hair care products? skin care? makeup? book jacket? album cover?), and another half-dozen I might give it as an editorial illustration. When I was a working pro, back in the Age of Acetate, those were almost all decisions I would have had to make at the time of shooting (you could just about make the decision to go from colour to black and white, but it wouldn't be the same as choosing to shoot in black and white to begin with). Today, rather than choosing contrast, saturation, sharpness and grain when you load the camera, you can postpone many of those decisions until post-processing, which means that a shot like this one is useful as a stock image today rather than being a one-trick pony. Anything from sizzling saturation to fantasy dreamland is possible with this image; there is no "right" treatment.

Solarization is almost always a mistake. When it works, it's gorgeous. It almost never works. And there's no good way to tell if it works until you apply the effect. (In the film days, when "solorization" actually had some "solar" in the process, you might find one good picture in three or four rolls of film. But you had to print them all to find out. Depending on the process you used, that would mean a hundred or so otherwise great pictures that were lost forever because you just had to try the solarization thing you saw in the book, didn't you?)

Even if the aim is simply to eliminate inappropriate effects from a menu of available filters (rather than to auto-process images), you'll probably be wrong most of the time. A monochromatic, smooth-toned abstract might fail as the photographer originally envisioned it, but it could make a very interesting picture if an edge-detecting filter is applied—it all depends on how you choose to define edge when you apply the filter. So your pencil effect might be best for the sort of pictures that anybody with any sense at all would disqualify from the effect without a second thought. That's art: sometimes the most interesting and appealing things happens because the artist threw away "sensible" for a few minutes and tried something idiotic.

The best you can hope for with automation (other than the sort of exposure correction and colour balance that the camera already tried to do) is to apply the most pedestrian and clichéd effects imaginable. Ooh, a baby—let's make that a low-contrast sepia B&W! Looks like lipstick—bump up the reds and kill the saturation everywhere else! That sort of thing. It's been done to death. You might as well just apply a fake faded '60s colouration to every image like everybody else and call it a day.

  • 1
    It sounds like Stan doesn't like Instagram :)
    – dpollitt
    Jul 31, 2012 at 13:19
  • 1
    @dpollitt - If only it were only Instagram... or only Instagram and Hipstamatic... or only Instagram, Hipstamatic and SnapSeed...
    – user2719
    Jul 31, 2012 at 13:38
  • "hate's a strong word" - but i have grown to hate the instagram effect... Jul 31, 2012 at 13:47
  • Hey I think Snapseed is awesome! I love that app on my iPad.
    – dpollitt
    Jul 31, 2012 at 14:22
  • 1
    ... but it has evil built in, and people use the evil. And then post it on my stream. Over and over and over again.
    – user2719
    Jul 31, 2012 at 14:29

I think that it would not be possible for a computer to determine when an effect makes an image look better to a human eye, a computer cannot understand context or emotion to make a decision if the effect is good, bad or ugly.

for example adding "warmth" to an image may make an image nicer to the human eye in some contexts, but in others it would look like bad white-balance.

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