Questions tagged [gamma]

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Problem on understanding gamma correction

I am struggling understanding gamma encoding/decoding. So the colors I see and the values I get from a color picker application(like MS Paint) are already in sRGB space(correct?). Assume the color ...
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1answer
45 views

Two questions on Gamma correction and Tonemapping

I have few questions regarding tone-mapping and gamma correction. is a tone-mapping operator a function whose output is a value between [0,1] ? If this isn't the case and since gamma encoding ...
0
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2answers
33 views

Does a bumpmap need to be linearized from sRGB when being read?

By a bumpmap, I mean the black and white height map, not the rgb normal map style one. If I were to convert a bumpmap to a normal map then I don't think I should linearize the values because if an ...
2
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1answer
123 views

Offline path tracer produces a darker image than expected

I've been going though Peter Shirley's beginner raytracing books. Upon building the Cornell box and rendering an image, I get a much darker / dimmer image than expected. The color values are ...
6
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0answers
112 views

Noise shaping for dithering with gamma?

The context of this question is correct dithering of color with gamma correction. In dithering we add (shaped) noise $n$ to a signal $s \in [0, 1]$ based on a random variable $r \in [0, 1]$ $$s' = s +...
0
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0answers
190 views

Path tracing - Better images without Gamma correction?

So I read about tonemapping and Gamma Correction recently and have implemented it in my path tracer. For the time being I'm using Reinhard tonemapping operator as described in his paper $L_d = L_w *...
1
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1answer
326 views

Gamma correction is done in an image or a monitor?

pretend the images and the monitor have same color profile Is every image from the internet commonly got gamma corrected? Or our monitor is automatically gamma corrected all the image showed up?
4
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1answer
300 views

Gamma correction and halftone

I'm writing a halftone algorithm, which takes standards RGB intensities in the range of $0-255$ and outputs black and white elements with a corresponding size ratio. Should I apply a gamma expansion ...
4
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2answers
577 views

Does a gaussian blur based bloom/glow shader require gamma correction? Any other tips?

Hello I have a simple application with some bright 2d mono-color shapes I am hoping to make appear emissive with a nice glow around them. To do that I am producing multiple gaussian blurs of varying ...
11
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2answers
1k views

Should the alpha channel be gamma corrected

We know that in PNG,BMP,etc... the pixel value stored is not in the linear RGB space. But I found no document saying anything about the alpha channel. Is the alpha channel stored in image files in ...
5
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1answer
300 views

Artifacts when gamma correcting

Doing post-process gamma correction is showing texture artifacts, here is a small example on a skybox: The first image is gamma correcting on the skybox shader and seems correct, the lower is doing ...
9
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4answers
2k views

Why shouldn't Bump, Normal and Displacement maps be gamma corrected?

So I'm trying to wrap my head around this from a fairly technical point of view. When you add a Bump or Normal or Displacement map in your shader they should not be gamma corrected. But diffuse ...
9
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1answer
233 views

Applying correct light physics to gaussian blur formulas for glow

I am trying to make a glow shader using separable gaussian blurring. I have recently been inspired by the short youtube video "computer color is broken" and I have messed with it with color ...
7
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1answer
348 views

Gamma setting in games - Why 3 icons?

Whenever I try to adjust gamma settings in a game, I am shown three different icons and usually asked to make sure the left-most one is barely visible. Example: What are the other two icons for?
7
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1answer
906 views

How are we supposed to fix brightness with square roots?

I recently watched this video that talked from a physics perspective how most of the ways we deal with color on the computer is incorrect because brightness is on a logarithmic not linear scale. ...
5
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1answer
94 views

gamma transform in webGLSL: when already done or yet to be done?

Color spaces issues are such a pain, especially when you create color data at the middle of the chain, and a pile of libs and apps separate this to the display... Here I only worry about gamma ...
11
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2answers
766 views

Should JPEG encoding take into account gamma?

When an image is encoded using JPEG, the RGB pixels are first encoded into YUV, and then the UV channels are downsampled. Before actually doing the DCT and encoding the coefficients, JPEG doesn't ...
7
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1answer
221 views

Brightness and contrast VS Gamma, is it possible to identify the gamma “correction amount”?

Trichoplax question aroused my curiosity and the answers in this question also reminded me why I sometimes use different gamma "amounts" to enhance images. Therefore, is it possible to determine the ...
17
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2answers
511 views

Is gamma still important to take into account?

Do different monitors (including mobile screens) still use significantly different gamma functions when displaying colour images? Is there a standardised way to represent colour that can then be ...