Hi, I had my living room decorated around seven years ago with a natural Calico emulsion which was made up by a now closed paint shop. I recently needed to apply some Zinsser stain block and I then re-coated with a Dulux tester pot, however the Dulux Calico is a slightly lighter tone and when the sun shines onto the wall it sticks out.. It's only a small patch of wall and I don't want to spend £££'s on a tin of Dulux and then add a slightly darker shade to match the original. Is there a shade of emulsion which is a very slightly darker shade to match Calico or can anyone come up with a suggestion to solve this problem. Many thanks in advance.