layered sky

[gungajim]

<p>I periodically get this horrible layered sky effect. Can anyone tell me what I do with my camera to cause it and what I can do with PS2 to fix it.</p><div></div>

[peterbcarter]

<p>That's from running out of colours in your colour profile. You need to switch to a bigger colour profile and process in a form that does 16 bit colour, like tif.</p>

[photomark]

Adopting in a 16-bit workflow may help. A 'bigger' profile probably won't help, if by bigger we mean a color space with a

larger gamut; it may actually exacerbate the problem. Remember that all 8-bit color spaces have the same number of

colors, one isn't really bigger than another, the colors are just spread out differently, some over a larger range of colors.

One of the disadvantages of working in color spaces with very wide gamuts is that you can get posterization rather

easily when you start pushing colors around.

 

You can think of colors as discrete steps which are usually so close together that they appear smooth. As you make

corrections in an image like yours, you are taking a range of these steps and spreading them over a larger area such that

the steps become visible. This happens a lot when you make corrections, but is often only obvious in areas we know

should appear smooth, like a blue sky. When you move to a 16-bit color space you effectively get more steps in the

same amount of space giving you more latitude to manipulate.

 

Shooting in RAW mode will let you make corrections while the image is still in a higher-bit space, which can help the

problem, but you'll need software that allows you to work with raw file.

[patricklavoie]

<p>Why do people alsways suggest 16bit? When i see this major banding effect it just tell me you shoot in jpeg and that you use a even lower compression method to upload your image, causing this problem.</p>

<p>Sure shoothing in raw, 16bit would help to a certain extend, but if you use a low compresion method, this problem will reappear again.</p>

<p>Heres a 8 bit images well process..any banding?</p><div></div>

[photomark]

<p><i> Why do people alsways suggest 16bit? </i><br/>

<i> Sure shoothing in raw, 16bit would help to a certain extend</i><br>

 

I guess you answered your own question. Not that I disagree with you that the image above is likely being degraded by jpeg

compression (perhaps multiple jpeg compressions), but depending on the camera, shooting situation, and the post

processing, shooting in raw and a higher bit depth can help enormously. I have had banding problems in areas like smooth

grey studio backgrounds if I shoot in something other than raw, even with high-end digital backs—they are not nearly as bad as the OP's image, but the

problem is solved, by shooting RAW. That's why people suggest it. That's why Adobe has made it a more important part of

the workflow. That's why camera manufactures allow us to get at the higher bit-depth data. </p>

[patricklavoie]

<p>Mark, 16bit is not always needed and not always the answer for everything. Whe had a long discusion on another thread month ago about that.</p>

<p>I dont say that 16bit is not good..i say that not because you see a poor image uplaod here that mean that a 16bit could have done it. As i show you here, a well shoot and developed 8bit could also do it. But i agree that for most landscape image with a lot of sky, since you are shoothing in raw, why not put all the chance to your side and use the full potential of your camera.</p>

<p>As fot the studio banding, i know a lot about it, and i can tell that by simply being cautious not to put too much contrast over it (protcting it with a mask) would really help the cause..8 bit or 16 bit..if you protect those *problem* area you wont get banding. Most of the shot i receive come from a 5D, 5D mark II, 1DS mark III and P45. Not much are developped and work as a 16bit image ; )</p>

[jcoffin]

<p>As has already been implied, over-processing and excessive compression are the major culprits here. As has also been pointed out, one way that helps avoid the problem is using 16 bits per channel. Patrick's right, however, that it's neither necessary nor sufficient -- you can avoid the problem with 8 bits per channel, and you can still get the problem with 16 bits per channel. Though nobody has stated it outright: it's better to avoid this problem than try to fix it.</p>

<p>On the other hand, if you've lost your original files, and all you have is a file with this problem, the problem can usually be fixed, or at least ameliorated. The problem generally shows up in areas like the sky, where you don't have a lot of detail. That lack of detail makes the problem more visible, and also makes the "fix" possible. The basic idea is pretty simple: select the area that has the problem, and then blur it so the problem is no longer visible.</p>

<p>For example, I took your picture, selected the sky area (rather sloppily -- I ended up with a bit of the trees as well, but was too lazy to fix the selection) and then did a gaussian blur with a radius of around 7 or so. What you're looking for is the smallest radius that almost makes the banding disappear. That will get rid of the banding, but the sky will generally look a bit artificial, almost like a piece of blue plastic instead of a real sky. You can generally fix that (reasonably well) by adding a little bit of noise to the same area. I typically find about 0.7% noise to work reasonably well.</p><div></div>

[chawn_crawley]

<p>If I was going to play with color space, am I correct that I would have to change the color space in the camera as well as in Cs3?</p>

[jcoffin]

<p>Not necessarily. The color space you set in the camera only affects the JPEGs it produces, not the raw files. For raw files, the color space is controlled by the raw conversion program. For the question at hand, it's really the color depth that matters more than the color space -- and JPEGs only support 8 bits per channel. If you want to use 16 bits per channel, you (nearly) need to use raw format (a FEW cameras can produce 16-bit TIFFs, but camera raw is usually a better choice).<br>

<br /> If you are using JPEGs out of the camera, that's probably the first thing to change -- every time you edit and re-save a JPEG, you tend to introduce more compression artifacts, just like you had in your original photo. Generally speaking, you want to get the data in raw format from the camera, and save in a lossless format like PSD or TIFF, and only do ONE conversion from that to JPEG when you're ready to use something in that format. Once you turn it into a JPEG, however, you're best off treating it as read-only -- if you want to do more editing, do it on the original, then produce another JPEG.</p>

[chawn_crawley]

<p>Thanks. I shoot in raw and use aperture, so I guess I don't need to tinker with that.</p>

[jcoffin]

<p>Right -- in that case, you'll choose the color space and channel depth in Aperture.</p>

[brad_smith8]

<p>If you see banding on an 8 bit monitor, you won't necessarily see it on a print using a properly color managed workflow. I use 16 bit prophoto all the way through to max out quality.<br />But if you just want the screen image to look better, convert the image to 8 bit sRGB.</p>

[gungajim]

<p>Thanks to all of you who have commented. I have a lot to digest!</p>

[sasvata__shash__chatterjee]

<p>Regarding the color-space setting in camera for shooting raw, I was led to believe there is a subtle difference, at least for Nikon DSLRs. Somebody please correct me if my understanding is incorrect. It is true that the setting of color-space does not matter for a raw file during capture, it is only important for the raw conversion and you can choose it during post-processing. However, the in-camera color-space setting does matter for the display on the LCD and the histogram. The LCD display is based on the embedded JPEG inside the raw, and the embedded-JPEG honors the in-camera color-space setting. If you choose sRGB, then the colors shown on the LCD are very representative of what you would see in the JPEG, but the histogram may be overly conservative and show clipping when there is actually none in the raw file. If you choose AdobeRGB, then the histogram will be more accurate but the colors may look slightly off. So choose your poison :-). I like to confirm that the exposure is correct more than that the colors are accuarte, so I choose AdobeRGB.</p>