You can have BM colors mixed in SW paints. I have done that with BM Nantucket fog.

I've not had good luck with our local Sherwin Williams at color matching. The BM Linen that they matched for me was very close, but had a hint more yellow than the actual BM. I think that's due to the slight variation in their base paints.

Lori, where do you get the Delta E values?

cawaps, there are a couple resources. Easyrgb.com is a trusted resource but you do have to understand all the numbers in order to compare colors and find the difference. Not hard to learn, it's just basic colorimetry.

Also, the hand-held colorimeters. NIX Sensor and the Color Muse.

I use both colorimeters for different reasons. For example, NIX captures with a D65 illuminant, Color Muse captures with a D50 illuminant so I can compare colors in different light sources, color temperatures - and other stuff.

They both have free apps. Like easyrgb, you do have to know how to use the color measurements (captures) to navigate within the free apps and get Delta E values. Again, basic colorimetry.

Here's what the NIX Sensor app comparison feature looks like. BenM's Wythe Blue HC-143 is on the left, Stratton Blue HC-142 is on the right.

Thank you Lori! That was really informative! In the meantime, I'll take a look at Argos and Chelsea Gray.

Ask the paint store too. SW has a few new colors that I don't have in my digital library, so there may be other decent matches to Coventry Gray.

Look at SW Cape Cod Gray

no such color on SW's website