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Why is there weird artifacting behind her head?
Hi there, I shot and edited this portrait. I noticed on my cell phone that there is some very obvious weird artifacting behind the subjects head. Why is that? Do I have to photoshop it out or perhaps totally replace the background with a solid black? Just want to understand why this happened, it looks like a mess on my phone and how to avoid/fix it. Not as noticeable on the desktop monitor. Thanks. Ronald (this is a screenshot from my phone)  Oct 25 16 12:16 am Link RonaldLee wrote: Insufficient bit depth + compression. Do I have to photoshop it out or perhaps totally replace the background with a solid black? Blur it and apply slight grain to match the rest of the image. Or (if you are starting from raw) develop it properly. Just want to understand why this happened, it looks like a mess on my phone and how to avoid/fix it. Not as noticeable on the desktop monitor. Your desktop monitor may not e properly calibrated. It is visible. (this is a screenshot from my phone) Google drive links should be shared directly as links. It won't allow you to embed an image the way you do. Oct 25 16 12:41 am Link Your image isnt working Oct 26 16 04:26 pm Link Budhi Malu wrote: Oh sorry, I didn't realize that it wasn't. I'll report below with more observation. Jan 31 17 01:50 pm Link Hi, I wanted to share some more things I noticed about the images, which may actually be affecting your images as well. As I mentioned, I shot some people against a black background. Here is how it looks after editing, and on my desktop computer.  But when I look at the same image on my cell phone, I see this, with the artifacting behind her.   I don't know if it's coming from the camera itself or if its part of some initial conversion process I am using, but on some of the images with the 'solid' backgrounds, particularly the black backgrounds, there is some really noticeable blotchy artifact. This sort of thing probably came from some image format compression (usually from higher bit depth to lower bit depth) or it could be something else. I see it only on my cell phone but less so on the desktop. So perhaps it is likely the higher contrast on the cell phone or lesser display capability. So.... .in order to avoid this in the future, I'm thinking that we may have to replace the solid color in the back with a photoshopped background that is still black in the case of black, or etc..... What do you think? Have you noticed anything like that? Is it likely, its just something that is inherent in the file and will happen no matter what? Jan 31 17 01:53 pm Link My initial reply still applies. The differences you see are most likely due to different color profiles used by your laptop or phone to render the image. To avoid such effects shoot in raw format, expose to the right, work in high bit depth and export to final format at the end of the process, choosing proper compression value which doesn't create artifacts. I recommend also to read about the linearity of raw format. In general shooting a person wearing black clothes on black background would benefit from some additional side/back lighting to accent where the suit ends and where the background starts. Jan 31 17 03:37 pm Link I am seeing it to the right of the head as well. ("as seen on phone" version) Could be the algorithm defaults used in the phone - equivalent to the quality setting when saving jpeg with Photoshop (like a 5) Data storage space is at a premium in a phone, it would make sense to use aggressive compression. The bit depth of the phone display is also a question mark. Suggest cloning a smoother piece of backdrop into the jagged areas ti fix if it's a one of. Jan 31 17 05:01 pm Link I think it's mostly compression. You get similar results if you compress quality to 50% or less. BTW, have you tried uploading to Dropbox (or something similar), then viewing on your phone? Just trying to isolate if your phone is compressing more if stored locally vs viewing online. Jan 31 17 06:21 pm Link JPEG compression is terrible at smooth, gradual gradients – it seems especially bad near black. This is a much bigger problem with motion video, where you're always compressing this way, and it creates this awful blocky noise. There was an alternative format to JPEG I remember gaining some traction a few years back which fixed that issue.. The thing is, in detailed pictures, it can get away with it. Three things I'd do: 1) Raise your black point slightly; 2) Use light to make sure there's a gradient/continuous shading on your background; 3) Use a background with some texture (along with the gradient, it makes the compression algorithm work harder and hides colour stepping in the detail). And like Anchev said: background subject separation. Move the light closer or use a background light to make sure they're in different tonal ranges.  Feb 01 17 03:06 am Link RonaldLee wrote: I've only had a similar issue once. I edited some image in PS and saved the jpeg. The issue actually went away when I exported from Lightroom to PS, edited, and saved to jpeg from Lightroom. It was an issue with color space I believe, I don't recall exactly. Feb 01 17 01:02 pm Link |
