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Part of the reason rescaled images look dim and blurry is because rescaling software usually assumes gamma 1.0 instead of 2.2: http://www.4p8.com/eric.brasseur/
by ivank 13y ago
Part of the reason rescaled images look dim and blurry is because rescaling software usually assumes gamma 1.0 instead of 2.2: http://www.4p8.com/eric.brasseur/gamma.html http://www.4p8.com/eric.brasseur/gamma.html
There are many more good essays on image rescaling here: http://entropymine.com/imageworsener/ http://entropymine.com/imageworsener/
- darkstalker 13y agoIt's because downscaling is technically a digital filter, so it can smooth the signal and cause ringing artifacts.
- Camillo 13y agoPreview.app in OS X scales the picture correctly. I think any program that uses Cocoa/CoreImage/CoreGraphics etc. to scale images on OS X should get the right result. However, Safari ignores gamma and produces a flat gray rectangle when scaling down the Dalai Lama image, like Firefox does. I seem to remember that Safari used to do proper gamme correction in earlier versions, but they were pressured to abandon it because it was more important to give the result expected by websites.
- Qantourisc 13y agoAnother issue is one needs to use a sharp filter during the resize, like sinc or something. Then post sharpening is not required in the first place.