Color Value Tool?
 

I am planning on making a version of the Thousand Pyramids quilt. This scrappy version relies heavily on placing your fabrics by value: Light, Med Light, Med, Med Dark & Dark. So now I have a pile of scraps that I need to sort by value. I've looked into purchasing one of those red filters, but just today I saw that you can't use just a red filter you need a green one too? I also remember folks talking about using B&W photos. Don't have a camera that shoots B&W. Can I pull a photo into photoshop & switch the colors?
Any tips would be great!

You can easily change a color photo to black and white in Photoshop.

I'll bet an Art Supply store could help you on your values. Or a paint store, like walmart or home depot, with their swatches. Just a suggestion.

you can place them on a copy machine and make a black and white copy

Or place pieces of the fabrics in question directly on your copier and copy them in black and white.

Jan in VA

Don't have a copy machine available (that's the only part of work I miss in retirement!), my husband has PS, so I guess I'll go that route. Thanks.

the B&W photo's are great ... but sometimes I want a quick look.

Heres some other items that might help in a pinch, and if it looks OK with these objects, then try the B&W photo

Green (empty) wine bottles
Glass of water with red food coloring
Colored cell wrap from gifts
Colored plastic file folders

You can also change from color to B&W in M/S Word.

A couple of years ago I bought a set of Cottage Mills Color Evaluator II strips. It comes with Two: a red one for using on warm colors and a green one for using on cool colors. Works great, handy to use in fabric store. Seems like I got the set on eBay for less than $10.

Most digital cameras can be set for black-and-white pictures. Some also have the option to do a digital preview in black and white (so you don't even need to take the photo; just look at the view finder). This can be a very quick way to check value gradations. Just line your fabrics up in what you think is the best graduation of value, and check with your camera.