From a spreadsheet I was using a while back and now updating, I had some
cells which had a pattern and a `fill` colour in them, I am sure I did this
from Format cells /Pattern /Colour.
It was a light browny beige colour but there does not appear to be a match
for it on the drop down color menu so when I take the nearest colour to it I
have two different shades. I cant fathom this out, have I maybe accessed a
tranclucent colour from somewhere that would make the older ones appear
lighter. I could change them all to the new slightly darker shade (but
prefer the lighter) but would still like to know what I have done.

Any ideas, I hope I have explained ok.