So sorry folks
I found this packet of 7 cards
all red back except one
In the photo I see that 3 red backs are marked in the center professionally
see photo
anybody know this packet trick ?

Sorry again
I cant seem to upload the photos

There are four 6 of clubs
one is a blue back
The other 6C are marked on the back
There is a 5 of spades red back
10 of diamonds red back
5 of Hearts Red Back

HI

I think I can paste these images now

Any help on what this trick could be ?

I don't know the trick specifically, but if you added an extra card you could display the faces as all 6 of clubs using a flustration count.

You could also display all the backs as red, and then produce a blue-backed card.