Here’s what I would do. Go to the local paint dealer(s) and scarf up as many “white” color chips as you can carry. Pick the one that works best as a background. Take it back to the store and have them make a sample size batch of their best latex paint. (Says latex on the can, but the binder is almost certain to be acrylic.)

Are you planning to color match those pears? Tricky.

I know you can mix colors. The difficulty comes in seeing the true colors. We all have a mental picture of a pear, complete with shape, color, texture and taste. These preconceptions about things like pears can get in the way of actually observing the objects.

I’m sure you’ll get it right; I’ve seen your work.

There are some things that can be done.

One possibility is to make an arbitrary decision about the palette. Select a color scheme and use only those colors.

Another is to use a color finder. That’s a piece of neutral gray material with a hole in it. Look at the color through the hole and match what you see. There’s a ready made tool called a view catcher available from both Blicks and Jerry’s Artarama. Or you can make your own. Just make sure that yours matches the value 5 on your value scale.

Yes, an 18% gray will probably work. In B&W photography I always used a 50% card. Just darker, that’s all. The main thing is having a neutral gray.

A gray scale and value finder is a good tool to have, and not expensive. A craft store may not have them but an actual art supply store certainly will.