Most Instagram photos have filters applied to make them look more retro/cool. Instagram users are also able to apply tags to a photo to help categorize and promote them to the Instagram community. One such tag, #nofilter, is intended to emphasize such natural beauty that no filter is necessary to enhance the image. (or the photographer is just too lazy to decide on a filter)
But how many #nofilter images actually have no filter?
As it turns not, not all of them.
After retrieving about 50,000 images through the Instagram API (code available on GitHub), here is the breakdown of filters on #nofilter-tagged Instagram images:
Only 83% of #nofilter images have no filter?! You had one job, Instagram! :(
The actual reason that this is happening is because Instagram rewards #tagspamming. More on that in a future blog post.