Edit from CS5 - Lightroom4 creating too big a file

[sanfairyanne]

I must have one of my preferences wrong because when I ask Lightroom to edit a photo in CS5 it end up becoming over 100mb per file. Whereas if I copy from Lightroom to the desktop then open in CS5 and do some edits it becomes roughly 60 mb. I recall there used to be a message in L/room asking if I wanted to Edit a Copy etc but that option is no longer available.
Can anyone suggest where I'm going wrong as I know it must be something simple.

Many thanks.

[john beardsworth]

Your LR settings look fine, so I imagine that your ACR settings are 8 bit. Maybe if you're worried about those 40 mb, it's probably time to get a bigger hard drive?

[sanfairyanne]

They're becoming 100+mb files, the thing is I can upload up to 60mb to Zenfolio therefore I can store full res' files on there as an online backup but now they're too big.

If I export a file from Lightroom to the desktop then reopen in CS5 there's no problem the file usually ends up around 60mb. The problem occurs when I hit PHOTO - EDIT IN - EDIT IN ADOBE PHOTOSHOP CS5