On 06/15/2012 09:51 PM, Keith Purtell wrote:
When I export a Web JPG from GIMP and it offers me a sliding Quality bar that goes 0 - 100. I want to know if that's an equivalent to the similar JPG quality setting in Photoshop? The reason I'm asking is that my research on Photoshop indicated that JPG output quality settings above 75 were "theoretical." In other words, there might be measurable improvements in JPG quality past 75, but they will be imperceptible by the human eye. Does anyone know if the Quality settings are basically the same in both pieces of software? In Gimp, the "chroma subsampling" is a separate setting from the "quality", while in some JPEG encoders it is part of it. This alone makes the quality setting potentially very different (but I don't know if this applies to PS or not). The perceptibility of JPEG compression artefacts depends a lot on the image. For the same quality setting, they are much more visible on images with sharp transitions and high contrast (computer graphics, text, or very good photos), than on "soft" pictures from low-grade cameras. |