Does this also happen when viewed at 100%?
Could you please post screenshots?
Thanks for your response c.pfaffenbichler,
I have attached some screenshots.
Before Adjustment.jpg is the photograph in Photoshop before I have applied an adjustment.
Preview Adjustment.jpg is the photograph as seen when I am previewing an adjustment (I have increased brightness quite a lot here in order to emphasise the problem).
After Adjustment.jpg is the photograph after the adjustment has been applied.
I have tried making an adjustment when viewed at 100% and this looks like it works fine.
Is this something you have come across before then?
It’s old hat …
When previewing Adjustments any display other than View > 100% is unreliable.
Depending on the Preferences Photoshop uses scaled previews to simulate the effect of Adjustments.
This does not become noticeable with many images but with especially noisy/grainy ones it can make a huge difference.
Thanks for your responses c.pfaffenbichler. I didn't know this. It's a bit frustrating.
I'll see if I can tweak the preferences to make it any better.
Thanks again for your time.
You can try setting the Cache Levels to 0.