I have used Avery business cards and labels for years. Previously I was restricted to the thinner cards due to laser printer limitations. It's amazing that even in the 21st century many standard colour lasers aren't rated for anything over 160gsm - and fewer and fewer have straight paper paths, even the mid-range ones that are rated for 215gsm card. Unbelievable. Anyway, I have a Canon Pixma Pro inkjet which has a straight paper path and appears to print on anything up to a paving stone! The results on these cards are great, and that includes a photo. These cards are about as heavy as you can buy, by the way, at 260gsm. You will find a bewildering range of Avery cards on sale and these are the thickest - I checked on the Avery UK web site. I have never tried printing on both sides: in my experience with many different home/office printers you are at the mercy of their paper feeds more than anything else when it comes to double-sided printing, so make sure your printer is up to the job and then you should be fine.