How to reduce the transparency of these curtains?

Hi all,

I am currently photoshopping this picture and I was wondering whether anyone could give me some advice on how to reduce the transparency of the curtains (in the bottom half a terrace and window frame are shining through)?

I tried playing with the 'Output Levels' on those areas, but the result is quite uneven. If only the folds were parallel I could stretch the top part over the terrace.

Thanks in advance!

Do one thing... Select only that curtains and copy it, then again make a new layer and paste it. you'll get your result.
Do this step 2 to 3 times when you'll get your result then merge your layer into the original one.

Regards,
Md Tafsil

if you mask the layer you can brush the picture away and it will become transparent, its the icon in the layer window below with the square and the dot in the square

also if you select you can click refine edge at the top where you can select brushtypes and feather you selection

If I understand your problem correctly:

Select the curtains using either the lasso tool, the magic wand tool or the pen tool.
Copy
Then paste in place with Shift+Ctrl+v
Fiddle with the opacity of the new layer until you are happy with the result
Merge the new layer with the original