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Questions tagged [gamma]

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19 votes
3 answers
4k 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 ...
Mary Chang's user avatar
17 votes
2 answers
610 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 ...
trichoplax is on Codidact now's user avatar
12 votes
2 answers
2k 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 ...
Mokosha's user avatar
  • 1,144
9 votes
4 answers
3k 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 ...
Kristoffer Helander's user avatar
9 votes
1 answer
312 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 ...
J.Doe's user avatar
  • 1,445
8 votes
1 answer
1k 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. ...
J.Doe's user avatar
  • 1,445
8 votes
1 answer
401 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 ...
Armfoot's user avatar
  • 615
8 votes
1 answer
731 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?
Simon Farshid's user avatar
6 votes
1 answer
121 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 ...
Fabrice NEYRET's user avatar
6 votes
0 answers
233 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 +...
orlp's user avatar
  • 186
5 votes
1 answer
6k views

Tone Mapping vs Gamma Correction

There is something about these concepts I'm not understanding. I thought the point of gamma correcting images is to make sure that the values in linear space map correctly when displayed on screen: ...
Rafael Sabino's user avatar
5 votes
1 answer
495 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 ...
V.M.'s user avatar
  • 53
4 votes
2 answers
1k 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 ...
J.Doe's user avatar
  • 1,445
4 votes
1 answer
468 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 ...
Tim Kuipers's user avatar
3 votes
1 answer
672 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 ...
user avatar
2 votes
4 answers
260 views

Question about function for color

I would like a help to understand the following line of code: return float3(pow(color.r, 2.2), pow(color.g, 2.2), pow(color.b, 2.2)); I've seen some places calling ...
Matheus Markies's user avatar
2 votes
1 answer
221 views

Gamma Correction vs Color Picker

I have some confusion regarding gamma correction and the output of my shaders. I'll start with the setup, then explain my current understanding of the matter, and finally the question. Setup I'm ...
Beko's user avatar
  • 123
1 vote
1 answer
676 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?
asuralhp's user avatar
1 vote
1 answer
564 views

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 ...
ali's user avatar
  • 740
1 vote
1 answer
298 views

Is anti-aliasing color processing correct in this image?

I have the impression that there is a problem with anti-aliasing in a 2D GUI framework using opengl. To demonstrate the problem I made a program that draws gray ramps. The result is shown below. The ...
chmike's user avatar
  • 121
1 vote
0 answers
668 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 *...
gallickgunner's user avatar
0 votes
1 answer
347 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 ...
ali's user avatar
  • 740
0 votes
2 answers
169 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 ...
Zebrafish's user avatar
  • 131
0 votes
1 answer
638 views

Converting from RGB Color Picker to Surface Reflectance

I am trying to derive the material reflectance values from a color picker tool(say MS Paint). My understanding is to first gamma decode(raise to the power of 2.2) the RGB values from the color picker, ...
ali's user avatar
  • 740