Correcting fringing in Photoshop

[bartonlew]

The screenshot below shows fringing (a green outline) around the top of the metal fence.  From what I've read online, this is also called Chromatic Aberration and is caused by the camera lens.  The fix to it in Photoshop directs going to Camera Raw Filter and following the steps pasted below the screenshot.  The problem is, Camera Raw Filter is grayed out for me (visible in screenshot).  Does anyone know why that might be?  Thanks.  

1. Open the file in Photoshop
2. Go to Filter -> Camera raw filter
3. In Camera raw filter, go down the options on the right hand side until you get to Optics
4. In Optics, make sure you can see the sliders inside the Defringe section
5. Click on the little eyedropper
6. Click on an area of fringing in the image – it should correct the chromatic aberrartion instantly
7. Close Camera raw filter by clicking “OK”
8. Repeat for different colours in the fringing as required

[D Fosse]

Off the top of my head I don't know why the filter is disabled - but what strikes me here is that you have a bad selection to start with. This isn't chromatic aberration, this looks like residue from the original background. Running defringe on this would just result in a dark "inverse halo" outline. I'd clean up the edge, and then the green will disappear.

[bartonlew]

Thanks.  But in the screenshot below, you can see the layer on which the selection was based (the selection layer above it is turned off), and it's apparent the fringing is in that layer too.  The selection was made by using the lasso tool to select from underneath the fence (on the aluminum frame) to the top edge of the file, and then Select Color Range to select just the fence, in order to lighten it only.  So in other words, the fence (using for example the Quick Selection Tool) was not the basis of the selection.  Do you still think it's the selection?  And does that affect how I resolve the issue?  

[Per Berntsen]

I see from your screenshot that the image is more than 82,000 pixels horizontally.

If you use the keyboard shortcut (Shift+Ctrl+A) to launch the Camera Raw filter, you should get this message:

[D Fosse]

Wow. It's hard to imagine any real life scenario where that would be justified.

What is the purpose of this?

[Trevor.Dennis]

The OP is also going for a new world record for the most number of Curves Adjustment Layers in a single document.  I'd be interested in what is going on here?

[bartonlew]

I document found or accidental art in NYC.  This is my most ambitous piece, a frame on a metal fence where Levis hung 156 posters for an ad campaign in 2016.  I found and shot it in late 2020.  The file is 586" W x 66" H, or about 80% it's actual size.  It's assembled from 152 captures from my Nikon D850.  The reason it's so massive is so that it can be printed and displayed at that size, as there is a lot of fine detail.  A section of the work is shown below.