What causes pixelation?

hark

Administrator
Staff member
Super Mod
Contributor
Yesterday I took this photo, but no matter how I edit it and upload it to Facebook, the sky gets pixelated. I even uploaded the full size yet still saw the problem. Normally I size the resolution for 240 and set it for 1600 pixels on the long side--which is how I normally resize my images.

I'm looking at this photo using the preview (before uploading) and still see some squares in the sky. Any suggestions? This was a NEF that was edited in Bridge then used a little PCC to fill in the edges from straightening. No gradient used during post and no CP filter because I forgot to take it with me.

Trenton Makes Walkway.jpg
 

mikew_RIP

Senior Member
Could it be to do with contrast fringing,i see it close to the bridge frame and through the infrastructure but not in the open sky
 

RocketCowboy

Senior Member
I've seen a few articles on how to size an image to try and get it past Facebook's compression algorithm. There are almost as many different suggestions on dimensions and JPG quality as there are days in the month.

I thought on Nikonites the limit was 1000 pixels on the long side before the forum software starts "optimizing" things.
 

Horoscope Fish

Senior Member
Yesterday I took this photo, but no matter how I edit it and upload it to Facebook, the sky gets pixelated. I even uploaded the full size yet still saw the problem. Normally I size the resolution for 240 and set it for 1600 pixels on the long side--which is how I normally resize my images.

I'm looking at this photo using the preview (before uploading) and still see some squares in the sky. Any suggestions? This was a NEF that was edited in Bridge then used a little PCC to fill in the edges from straightening. No gradient used during post and no CP filter because I forgot to take it with me.
Facebook compresses photos horribly. I mean, "Like, whoa..." compresses them.

The best, and simplest solution, I think, is to save photos you intend to upload to FB as .PNG files because .PNG is a lossless format; this will thwart FB's attempts to butcher your shots. The .PNG files will be larger (longer wait times to upload to FB) but the quality improvement makes it all worthwhile, IMO.
 

WayneF

Senior Member
I can't see it in the picture posted here. I assume Horoscope Fish is obviously correct about Facebook compressing your image tremendously more than the one you uploaded to them. They are trying to reduce their bandwidth.

Pixels become visible when the image is too small, so enlarged too much, so that the pixels become visible.

But JPG compression artifacts (caused at low JPG quality levels for greater compression) are seen as 8x8 pixel blocks, "squares" larger than one pixel. Also we can start seeing fringing around object edges in images.
 

Horoscope Fish

Senior Member
Some good reading on this topic from our good buddy Ken Rockwell :: How to Properly Resize Images for Facebook



HA!! Just kidding... Credit goes to Nasim at Photography Life. According to Nasim, FB isn't doing such a horrible compression job any longer. It sure used to... And it got me in the habit of uploading in .PNG so I guess this is one of those Your Mileage May Vary situations.
 
Last edited:

hark

Administrator
Staff member
Super Mod
Contributor
I have a feeling it comes from noise that I can't seem to get rid of. I used noise reduction in Bridge. I used Nik Dfine. And I used them together...still no luck in getting rid of the noise completely. I can see a little noise in the original file after it is edited, too, and that's where I see the most pixelation.
 
I have a feeling it comes from noise that I can't seem to get rid of. I used noise reduction in Bridge. I used Nik Dfine. And I used them together...still no luck in getting rid of the noise completely. I can see a little noise in the original file after it is edited, too, and that's where I see the most pixelation.


I used to have that problem a lot more until I realized that part of the problem was my processing. I had a tendency to over sharpen my photos. NIK is a great program and I really love the Viveza section of NIK but it is so easy to overdo the Structure slider. It looks great on your local monitor but any other place it really causes problems. Now I use it more for adjusting segments of the photo for color, brightness etc
 

BackdoorArts

Senior Member
I've heard from more than a few photographers that the best sizes for FB are 968px or 2048px on the long end (Jimmy McIntyre has them in addition to the every-100-px presets in his Raya Pro toolbar). Whatever they wind up doing to it those seem to survive the best.
 

hark

Administrator
Staff member
Super Mod
Contributor
I'm telling you I think it has to do with not being able to get rid of all the noise. If anyone wants to give it a go, here is a link to the original NEF. I reset everything back to default. Heads up--the file is 28.75MB.

https://www.dropbox.com/s/jws2ab7b9ew14u7/028.NEF?dl=0

After resetting everything back to default, I opened the file in PCC and simply ran Nik Dfine. This is the result. I can still see noise in the file without any other post processing done. I converted the NEF to a DNG for the following image since it is what I normally use. Previewing the image as I'm writing this, I STILL see pixelation.

I've never had this issue with any other files regardless of forum sizing. I swear it has to do with not being able to get rid of all the noise. For those who are interested, please have a go at it, and post your results below.

028 default & Nik Dfine.jpg
 

hark

Administrator
Staff member
Super Mod
Contributor
I went back today with the same camera/lens combo--the only difference was this time I used a CP filter plus the sunlight wasn't nearly as dramatic. It was very diffused due to the clouds.

I sized this using the same dimensions as the original image. Even upon previewing this image, I don't see any pixelation. No matter how I edited the first image, I couldn't get rid of noise. For this image, I used a monopod which allowed me to lower the ISO to 200. But personally I don't consider the original photo's ISO of 640 to be all that high, yet noise was a factor. In today's image, I didn't even use Nik Dfine because Camera RAW handled it quite well.

Most of you won't even give this problem another thought...unless it happens to you. And if it does, please zoom in on your original image and see if there is any noise where pixelation is occurring and also see if there is any streaking of color. Both were present in my original image which I believe contributed to the pixelation problem.

Trenton Makes Bridge wide angle.jpg
 

aroy

Senior Member
In RAW file you get 12/14 bits so there are more shades, but jpeg limits it to 8 bits. The pixelation may have to do with wide DR of your original scene. What it means is that there are more than 256 shades of blue in the scene, hence gradual change is not possible.
 

hark

Administrator
Staff member
Super Mod
Contributor
In RAW file you get 12/14 bits so there are more shades, but jpeg limits it to 8 bits. The pixelation may have to do with wide DR of your original scene. What it means is that there are more than 256 shades of blue in the scene, hence gradual change is not possible.

When I get a chance, I will try editing the jpeg version and see if that makes any difference. You might be correct with dynamic range being a possibility. The sky looks to be quite graduated in color although I didn't use a gradient filter. Obviously there is something contributing to the pixelation when it is resized. It isn't the resizing itself that causes it...but it is due to an underlying factor that becomes apparent when resized. At least that's my theory. ;)
 

hark

Administrator
Staff member
Super Mod
Contributor
Well...I sat down and edited the original jpeg to see if it makes any difference. Since I had reset the NEF, I erased my original settings in Bridge so I had to guess to replicate the settings and applied them to the jpeg. Some of the spot touching with the brush aren't the same though.

Here is the original NEF that I edited which is in my original post:

Trenton Makes Walkway.jpg



And here is the jpeg that I edited. Let's see if the pixelation problem still exits. Previewing the image, I still see pixelation. Sigh. :(

028 jpeg edited resize.jpg
 

hark

Administrator
Staff member
Super Mod
Contributor
I went back this afternoon and tried to replicate the original image. Here is the original image which displays some pixelation.

Trenton Makes Walkway.jpg


And here is the shot from this afternoon. The sky didn't have clouds this time although it looked a little hazy. I used a CP filter this time which I didn't the first time. And of course there was some snow in the first shot. As I'm previewing the image below, I still see pixelation. :eyetwitch: AAAGGGHHH! I can't believe it. Obviously I am only going to be able to capture this image when there are some clouds in the sky. :cower:

006 resize.jpg
 
Top