I did these with the naked eye.  I enjoy doing them a lot and because of that I did a bunch of them.  Then I stopped doing them because I really wanted to do larger painting where I could do so much more in the story I wanted to tell, so I returned to conventional sizes of larger oils.  Someone asked me about the little stamp paintings some time later and I decided to so some more.  I cleaned the glue from the back of a really good stamp, carefully taped it down and got my brush, only to discover that I could not see the darn thing close up.  In the intervening year or so I had slipped a little past the age of 40.  My eyes were going south fast.  It was a shock.  What!  But some drugstore readers fixed that and I was back in business. 

Gettin' Old is so much fun!