Thumbnails darken when not selected, Lightroom

[wilt]

When I go to import images, I always un-select them all and go through them selecting the images I want to import.
When I un-select them at the start, they all darken to show that they're not selected. This makes it quite difficult to see the image, unless I click on it and make it full size.
Is there a way that doesn't darken un-selected thumbnails, so I can easily scan them in thumbnail mode?
Also is six thumbnails across the largest they can be made? My eyesight isn't what it used to be.

 

[DemiLion]

Select all and then deselect the ones that you don't want.

As for getting larger thumbnails, see below:

 

[wilt]

I do that at present, but I'd prefer to be able to see the thumbnails clearly and select only the ones I want. As sometimes I'm looking for one shot out of a long burst.
I have the thumbnails slider right across, but it only goes down to 6 in the import screen, it will allow down to 3 in the library module.