September 16, 2009

tonemap THIS

Filed under:, , — cwage @ 10:22 pm

Okay, people. There's a disturbing trend and it needs to stop. Photoshop CS3 (and maybe CS2) incorporated the ability to tonemap an image. Tonemapping is basically where you take an image with higher dynamic range and compress it down to a normal 8-bit image. An imperfect but suitable analogy is compression in the world of audio processing. (sortof). Anyways, it's a technique that is used often with HDR, because HDR is a process where you end up with a 16 bit image, but you have to show it to the 8-bit world, somehow, so you tonemap it.

But lately, I see more and more people using this effect on normal images -- portraits, in particular. The same algorithm will "work" on images of any dynamic range, so even if you don't have a RAW image (typically 12 or 14 bits), you can still apply it. And people are. I don't even know what the setting or effect is actually called in Photoshop, since I don't use it, but it's annoying and stupid and it NEEDS TO STOP.

I see it more and more -- I was just at the future50 awards and fully 1/4th of the images submitted had this weird effect applied. Take this image, for example, of the lovely and talented Yvonne, that I saw on facebook:


This image has been tonemapped. It looks WEIRD. Stop doing this. It was a perfectly fine picture beforehand. Stop making your subjects look like mannequins. Thanks.

End rant.

UPDATE: I hope no one I know took/processed this picture. If so, uhm, hi! I still like you.

September 6, 2006

HDR and Tonemapping in Linux

Filed under:, , , , , — cwage @ 12:10 am

I thought I'd write up my workflow for mucking around with HDR and Tonemapping in Linux. Actually, come to think of it, though, most of this software would probably work fine in Windows (pfstools being the toughest, but I bet it works fine in cygwin). But first, a point of clarification in definitions: most people associate HDR with tonemapping, but they aren't the same thing:

HDR stands for High Dynamic Range, and it's a process by which you can combine multiple exposures into one image that contains more dynamic range than one exposure would normally contain. These images need to be displayed on equipment that can display the range, or they need to be .. tone-mapped:

Tone-mapping is a process by which the high dynamic range is converted to a standard low-dynamic range image. There are many algorithms to accomplish this, and they all have different effects -- some realistic, and some not. (Some prefer to call it hyperreal or surreal. Whatever.)

I was loathe to write this up, since I haven't really produced anything that phenomenal, but I do have some tricks up my sleeves that other people with more photographic skill might find useful: