gamma

How can I make Internet Explorer not change the colors in my PNG images

When using PNG files (made with Paint.NET) as background images on my web site, IE7 is changing the colors and actually displaying a darker version of my images, as seen here. In this image, the dark background and background image should be both #001122, and the medium background and background image #004466. But IE7 changes the images ...

Tweak the brightness/gamma of the whole scene in OpenGL

Does anyone know how I can achieve the following effect in OpenGL: Change the brightness of the rendered scene Or implementing a Gamma setting in OpenGL I have tried by changing the ambient parameter of the light and the type of light (directional and omnidirectional) but the result was not uniform. TIA. Thanks for your help, some a...

How to scale pixels in an image to adjust brightness?

I have a grayscale image from a photograph. I've determined that certain parts of the image are underilluminated, and that a pixel with luminance Y = 0.8 should actually be adjusted to 90% grey, i.e., that pixel should be given luminance 0.9. My question is how do I scale the other pixels nearby? I'm pretty sure multiplying all the lu...

How can I get image data from QTKit without color or gamma correction in Snow Leopard?

Since Snow Leopard, QTKit is now returning color corrected image data from functions like QTMovies frameImageAtTime:withAttributes:error:. Given an uncompressed AVI file, the same image data is displayed with larger pixel values in Snow Leopard vs. Leopard. Currently I'm using frameImageAtTime to get an NSImage, then ask for the tiffR...

Antialiasing and gamma compensation

The luminence of pixels on a computer screen is not usually linearly related to the digital RGB triplet values of a pixel. The nonlinear response of early CRTs required a compensating nonlinear encoding and we continue to use such encodings today. Usually we produce images on a computer screen and consume them there as well, so it all ...

GetDeviceGammaRamp to adjust colors

Hi, I overlay an OpenGL application (c++), this openGL application uses SetDeviceGammaRamp to set the brightness of the desktop to very high (dont know why). This application is fullscreen and looks good, but my overlay is very bright. Instead of the orange color with normal brightness, I get yellow because of the high gamma. What I wa...

Fitting a gamma distribution with (python) Scipy

Hi folks, Can anyone help me out in fitting a gamma distribution in python? Well, I've got some data : X and Y coordinates, and I want to find the gamma parameters that fit this distribution... In the Scipy doc, it turns out that a fit method actually exists but I don't know how to use it :s.. first, in wich format the argument "data" ...

How to calibrate a Mac Monitor for iPhone development

How to calibrate a Mac monitor to match the iPhone's colours? What is the iPhone's gamma? Thank you. ...

PHP GD2: how to maintain alpha channel transparency and correct gamma

I was intrigued by this discussion of image scaling and subsequently found out that the PHP code I'm using to create thumbnails from uploaded images suffers from the same problem. I decided to try the PHP fix posted near the bottom (converting gamma from 2.2 to 1.0, resizing the image, converting gamma back from 1.0 to 2.2). This works t...

Why is this PNG mis-colored on Linux?

My site uses a PNG for a transitional background. Here is the site on Firefox on Mac, and here is the same site on Firefox on Linux. As you can see, the PNG background displays in a duller green on Linux. Is this due to the gamma correction issues described here? How can I solve this problem? I have tried using a JPG and also a BMP, but...