Color banding problem

[locusofeden]

Hi! I've googled this issue, and even saw a thread or two about this on here, but even after trying all suggestions I still am unable to get rid of weird color bands rather than smooth gradients in my raw photos. I'm using two colored led Pavo Tubes as a light source and so there should be a nice transition from one color to the other. But when I bring the photos into ACR I get hard lines/bands where one color stops and the next begins. After editing them in RAW and bringing them into Photoshop the bands are still there and the only way I can make them look a little better is through editing/smoothing the transiton. But there even after doing that there is still a very noticable line of color. I've attached examples of an untouched photo showing the banding as well as one of the same photo with vibrance turned down slightly which shows the banding even more, and then an edited photo still showing signs of the band. Also attached are screenshots of my settings. Please let me know if anyone knows what's going on here! Much appreciated!

[TheDigitalDog]

We need to examine the raws themselves. Can you apply any desired edits, then save out a DNG which will embed those edits and the raw, then upload to something like Dropbox.

Banding can be in the image data but also only be in the display path. Need to see the data in a DNG to get to the bottom of this.

[locusofeden]

Here you go!

https://drive.google.com/file/d/1sxzqeZoa6MKzbxwRpol2D0bEYLX7-n_U/view?usp=sharing

[TheDigitalDog]

I think I see what you may be referring to. I've opened the DNG in Camera Raw with your settings and at 100%, placed two arrows where I see harsher transition of color (not what I'd call banding). I'm placing a TIFF (JPEG compression not ideal) in my Dropbox, the screen capture is in the display color space but should preview correctly as such in Photoshop.

https://www.dropbox.com/s/yf3ggt9mggk1e9u/Banding.tiff?dl=0

As to why?

I opened the DNG in RawDigger, it is perfectly exposed. But I do see slight banding in the red channel (the others look clean). Not sure if you can see this in the screen capture I'm placing here.

What this tells me is this is a sensor issue or something like that, not ACR engine, its in the raw data itself. We can go into details about why this might happen, how sensors "see" (sorry but that's the best term at this point), is complicated and it could be due to camera metameric failure. But it isn't the raw processor. It is seen in the raw data. From RawDigger

[locusofeden]

Thanks so much for looking into this for me. I have a basically brand new Sony a7c camera. I'm generally not super technical, but I've been under the assumption that this is a fairly high end camera. Are you saying that there is potentially something defective with the camera? Or an inherent issue with the camera itself? Any suggestions on remedying this? I'm very much into the lighting setup I've been using and hate to think that this will be a constant issue. 

[TheDigitalDog]

Are you saying that there is potentially something defective with the camera? Or an inherent issue with the camera itself?

By @locusofeden

Not at all. It could be due to the light source, or just the color spectrum in the image. I doubt you see this in all images right? I'd suggest testing this with either a different illuminant or color gel and see if you can reproduce this or not. What I do believe is, no matter what raw converter you used, it would show up as it appears in the "red channel" of the raw. At least in this image.