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19

This is known as "banding". Dark parts in the picture have a small range of values (in a JPG, you only have 256 values per color), when you lighten them, you increase the gap between consecutive values as much as the values themselves. Since the gaps more or less follow a line they are very noticeable by our eyes. Several fixes are possible : If you have ...


18

I don't use Photoshop, so here it is done with Gimp, but I assume the same tools are available on PS: Use Wavelet decompose to decompose the image into its frequency components (these are images that are progressively blurrier and which added to each other, rebuild your initial image). By flicking the visibility of each layer, identify which layers carry ...


17

I actually wouldn't describe what you're seeing as a halo artifact. It seems to me to be posterization — there just aren't enough tones to smoothly represent the gradient of the sky. It just happens to be in a circular pattern because in this image the center is brighter and then diminishes evenly in all directions. In a different image, this same effect ...


12

This "banding" is caused by the primary light source in the image varying in intensity over time, and by the (electronic) rolling shutter in the camera converting this variation over time into variation in illumination across the image. This changing illumination affects the image multiplicatively — i.e. the brightness of a pixel in the image, on ...


10

The image has some highlights where there is some blue mixed in, where there is otherwise only information in the red and green channels. It's those highlights that doesn't balance well when you desaturate the image. You can use the Channel Mixer in Monochrome mode to convert the image, that allows you to balance the channels to avoid the posterising. ...


5

This is named banding. And it's caused in your case by overprocessing the image. What you can do is to take the photo in RAW and postprocess it. When postprocessing mask the sky and do not increase the exposure there. At the end night sky is dark. You can also take two photos, one as it is and one for the buildings. And mix them keeping sky dark and ...


5

I think what you're seeing is called banding or posterization. This is where smooth, continuous tones are rendered in a stepwise manner because the bit depth (the number of bits used to represent each pixel) is limited and the jump between pixel values is large enough to be visible. Because the image is still in Darktable and hence is 16 bit (which is enough ...


5

Probably the word you search is "banding". You can get more information here. Quoting: Colour banding is a problem of inaccurate colour presentation in computer graphics. In 24-bit color modes, 8 bits per channel is usually considered sufficient to render images in Rec. 709 or sRGB. However, in some cases there is a risk of producing abrupt changes ...


4

A pixel can be understood as a 3-dimensional thing. A pixel holds information. How "deep" this information can be is the trick. Pixel Depth Here is a representation of one pixel. On the left, it can potentially hold information about any of 4 stages. On the right, it can have more options or levels to choose from. But "resolution" is ...


4

Image resolution (amount of pixels) and bit depth (bits per pixel) can be changed independently. Any combination of high/low resolution and more/less bits per pixel is possible. Sometimes, however, higher resolution can make up for lower bit depth. Individual pixels become invisible and we start perceiving patterns of pixels as shades, as if the color depth ...


4

Way back in 2014 Canon introduced a feature with the 7D Mark II that they called flicker reduction. Basically, the camera uses the light meter to detect the timing of flickering lights and then times the shutter release so that the middle of the exposure coincides with the peak of flickering lights. Remember, with focal plane shutters the time difference ...


4

This is a valid concern. My understanding of your question is that it's a monitoring problem rather than editing problem. That is, when you are editing an sRGB photo, you specify that your current worskpace is sRGB, instead of converting it to AdobeRGB first. In this case, all your editing is happening with full 8 bits (or 16/32 if you select so in the ...


3

The effective trick for this is to double the resolution of the photo, add a very small amount of stochastic hue-constrained noise, bring the resolution back to original, and THEN de-noise. There is already significant banding in the original, by the way...which I find way more annoying than any noise, which seems pretty minimal. Edit: These two photos ...


3

This is known as "banding". This happens when you have uniform color gradients and the quantization by the camera (because JPEG is only 8bits/channel) transforms them into uniform areas. Along the edge of these areas the value "jumps" and our eyes are quite sensitive to this. This can be checked with the histogram, which assumes a hair comb shape (the ...


3

Even when the sky appears uniform to our eyes, it isn't. The index of refraction of air is affected by a number of things (e.g. the shimmering mirages you see over a hot road) - temperature, humidity, turbulence, pollution, density due to elevation, and probably others - especially at boundaries where one or more of these change rapidly. In addition, just ...


3

The vertical refresh rate of the screen is around 60 Hz, but the horizontal refresh rate is much higher. Each line of the display is refreshed from left to right during the vertical refresh. With a vertical resolution of 1280 lines, it means that the horizontal refresh rate is about 76800 Hz. As the exposure time is about 5 times that, it makes sense that ...


3

You have diferent issues here. Lets separate them. 1) You have a bright wall and dark people... It is the same case as if you have a bright window with people on an interior. Your options are limited. Use aditional ilumination, like firing a flash as fill light. If you are shooting from far away this could not work. But if you have permissions you can use ...


3

Banding is very difficult to remove. If you are lucky, the band itself has no falloff of light in itself. Which it seems is not the case here. However, what you could try, is to basically equalize the striping via dodge & burn in Photoshop. For that, create a new layer in Photoshop a levels adjustment layer. Then create a mask with a strip pattern that ...


2

Your ways are: using any film to record images instead of digital technology using the camera with strong enough AA filter using the camera with surplus of resolution (medium format cameras, may be very expensive) using very tight aperture (big F number) so that image is blurred enough with diffraction for moire to disappear. 1,5x crop camera with F13 will ...


2

I have made a circular 8 bit gradient with sampled edge colour and center colour. This illustrates that it clearly is not the 8bit quantisation problem. I have also took a stare at the source, non-denoised image and I found posterisation there too! This posterisation is already there in first image, denoising only reveals it. There cannot be any ...


2

What you are seeing is the refresh of yur monitor, probably 60Hz. You can prevent that by shooting at a longer shutter speed, which means reducing the ISO value and/or your aperture (=bigger aperture number). Just try a few different settings. A tripod will probably be helpful, to prevent camera shake at those slow speeds. Edit: i'm just seeing that you ...


2

You note that the pictures are CR2 images. These are Canon RAW files — they are not, in that state, usable for sharing and printing and so on. You need software to convert them. The most popular such software is Adobe Lightroom, but you can also download Canon Digital Photo Professional for free — or use open source software like Rawtherapee. The key thing ...


2

Not in common digital imaging terminology. Instead, we call bits-per-pixel bit depth. Once unpacked from whatever compression format they were stored in, digital images are usually represented as triplets of red, green, and blue ­— each of these is a "channel". (There may also be a channel representing transparency, although that's more of an image editing ...


2

The actual problem occurs due to the accuracy of the math (editing bit depth) and not the color space itself. I.e. you can edit in sRGB with 16 or 32 bit accuracy in photoshop and (largely) avoid the 8bit banding issue.


2

That is a readout issue that can occur with CMOS sensors. It is essentially the same thing as CCD "smear;" only in a horizontal direction rather than vertical, and CCD sensors are much more prone to it due to the difference in readout technologies. It will only occur with a very high contrast source against a very dark BG, and usually only visible ...


1

In my opinion this can be some normal background noise generated by the sensor, amplified by Your post-processing. I found a similar pattern at high magnification on pictures taken with Olympus E-510 with noise filtering turned off. Here You have the E-510 noise (white sheet of paper out of focus, picture mode "vivid", ISO 100, low sharpening, noise filter ...


1

These are dark images (cap on). With severe stripes it can be very noticeable on uniform lighting and sharp contrast transitions as well but it is most prominent in low light scenarios. The increase is likely caused by the buildup of heat in the sensor. The longer a sensor is energized, the warmer it will become and the noisier the output will be until the ...


1

Even if you processed the raw files initially, when you upload them to sites such as google photos, they may compress them further to reduce the bandwidth needed to transmit them to viewers. This compression can also cause banding.


1

Banding is due to quantization. If you have a very slow and regular color gradient, and not many available values dues to low bit-depth (8-bit channel), at some point along the gradient adjacent pixels fall together in the next "value slot", so there is a line in your display between the pixels in the previous slot and the pixels in the new slot.. The best ...


1

What you may be seeing is fake banding created by Photoshop. It takes shortcuts to display layered files more quickly that sometime affect the actual appearance of the image on the screen. To check to see if there is actual banding, you can either zoom into the image to 100% or temporarily flatten the image to remove the layers. If what you are seeing is a ...


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