BySqueesh

Nope, no change at all setting photoshop to the same monitor profile (not with the banding/posterization issue, didn't check any colour differences out) Got firefox and set up as your guide suggests.

Strange, I had replied to these comments but it obviously never went through (I wondered why the thread was so quiet hah!) I did and it didn't change anything. I use Google Chrome I'm still struggling to find a fix. I've just upgraded from Windows 7 to Windows 10 and the problem is still very apparent. Literally out of ideas to fix this.

Sadly didn't work

Just downloaded and opened the PSD file, the issue is definitely there for me. About to follow the steps you linked (blackboxes/weird behaviour one)

Oh god duh! No I didn't, and opening it in photoshop shows the same problem, it's a much smoother gradient than anything I have been able to create so far, but it's still apparent when opening that image of yours in photoshop

Perfectly smooth on both of my monitors

Yea it's still there. With a gradient it's less posterization and more a large block of black then a harsh transition to grey (regardless of my settings/the scale of the gradient) I guess it's a similar issue the soft brushes are showing though, a hard edge black in the middle and a nasty transition to grey, the brushes just seem to show more grain/banding with them too

Sorry for the delay in response! I checked the cables and they were still firmly plugged in. Yes just one monitor is calibrated. I ended up formatting my PC as I couldn't find a solution... and the problem is still there with a fresh install of photoshop. I took a look at my graphics driver updates and noticed there was a new one released around the time the issue began, so I tried an older version of the drivers but that did not fix it. I even went back another driver version but again, it didn't fix it. My partner installed photoshop on his PC for comparison sake and he had the exact same issue. What I don't understand is that I can view gradients fine when I don't create them, no other images on my computer look strange - for example, my desktop background is fine, browser images, windows photo viewer etc are all smooth. But when I create something with a gradient (either the actual gradient tool or soft brush), in Photoshop or Krita (a free painting program, installed for comparison) that's when the problem occurs. I did notice the issue is more apparent depending on what colour profile I use in Photoshop - I usually work in sRGB IEC61966-2.1 with my colour mode RGB/8 bit. Other than buying a new PC and hoping it doesn't have the same issue, I have no idea! And any examples of people with similar issues I've found through google have no real fix.

The problem was before I reinstalled the graphics drivers. The re-installation was an attempt to fix the problem

Yesterday (Tues 29th) I was painting the day before that and everything was fine

Ok so calibration redone (followed your instructions again) and the issue is still there. I also downloaded a free painting program (Krita) to test the brushes in and I find I have the same problem in there, albeit not as apparent. I can only assume it's a problem with my graphics? But the drivers were reinstalled yesterday. My only other idea would be to format. What are your thoughts?

I'm using Spyder 5 Elite. I'll get it redone as soon as I can (which sadly now is tomorrow evening, 11pm here arrggh) Reet hopefully that'll do the trick, I'll update and let you know as soon as. Thanks again for the help, really appreciate the time you give Hannah

On a perhaps related note, I've just tried looking at my monitor calibration software and it's throwing up some errors "The calibration data from the profile was NOT LOADED into the video card." tells me to open Datacolor>ProfileChooser and when I do it tells me it's empty... could this be the issue?

Really? That's interesting! How do I know what my monitor profile is? (Sorry I'm not the most techy person) in the Assign Profile I get 3 options: Don't Color Manage This Document Working RGB: sRGB IEC61966-2.1 Profile: With a very large drop down list

Done, thank you for taking a look!