CompuServe Messages

Martin – Granted its a little confusing when you REALLY try to understand what's going on, rather than relying on a preset formula. When you render to the Framebuffer the gamma value specified for the Framebuffer applies, ie you see the effect of the gamma correction on your rendered framebuffer image. You seem to be very clear on this. >>Which value is used when rendering both to framebuffer and disk? << The framebuffer gamma value is displayed and the output file gamma value goes to disk. You can check this by rendering a frame buffer value different than your output gamma value and saving the rendered image to disk. Then when you "view last" you'll see the difference between the output file image and the rendered image that you previously saw in the framebuffer. Which is why its a good idea to keep these values the same. The rendering in 48bit space is transparent to the user and gamma correction is only applied once to the final rendered image. Input file gamma takes the image in its standard state, whatever gamma value it has. By applying the same gamma value as the framebuffer and output file, you are keeping the input file gamma neutral, in other words you're not changing its original gamma value. If the value is not the same ie: its lower, then the picture becomes darker and if the value is higher than it becomes brighter. By adjusting the Input Gamma value higher than the ouput file gamma you can doulbe gamma correct or gamma correct the input file image depending on whether it was gamma corrected initially or not. I prefer to gamma correct the image before I use it. Then when using that image in rendering, by keeping the Input file gamma value the same as the Framebuffer gamma and Output-file gamma, this maintains the Input-file-image's gamma value I previously corrected the image to. I also set the USE-TGA-GAMMA = OFF Hope this clarify's gamma correction for you. Essentially the rule of thumb is to keep the gamma values all the same. I don't rely on Display gamma as I have a Framebuffer. For those will only a Display you would want that to be consistent with Input and Output Gamma values. And gamma correct for a specific image before hand if you need that image gamma corrected. I find this less confusing.