Looking for correct color measurement system for textures

We are looking at a stair tread system , specs call for a 70% contrast in color between the nosing and the rest of the stair. So far so good, as I have a spectrometer here. Here is the issue, the stair treads are arc-sprayed material on steel. This means there is a very rough, textured surface that really has no color other than the various irregularities formed by the arc spray. My thoughts are that comparing one base (master) piece to the sample will not give me contrast, but distance between colors (delta E) (is that 'contrast'?) and only perceived color since it is really a reflectance issue, not a color issue. What is the proper measurement system for 'textures' as opposed to smoother 'colored' surfaces?

 

Ok, I got a bit further on this. It appears I need to measure LRV (light reflectance value) for this, Can I do this with a color spectrometer? The spec on this states "the material used to provide contrast should contrast by at least 70%". Attached is a pic of what I am dealing with.

 

I don't have an answer for you, but I feel for you regarding the challenge. If I had all the time back I spent chasing color issues, I could live another life

 

Hi, there is one suggestion. Please contact some Spectrophotometer suppliers like:
1) DATA COLOR
2) GRETAG MCBETH
3) X-RITE OR MINOLTA
4) HUNTERLAB (since they provide equipment for LEVIS DENIM which has some sort of TEXTURE - ie. Blue Yarn and White Yarn in contrast).

Other solutions are Machine Vision Technology Sensors, but note sure about Stair Tread Systems.
I think Mechatronics or some instrumentation maker might offer you some sort of solution. You may check some Books as well for referencing.

 

We have an Xrite, but it is limited to L a b values and does not give LRV results. I did find some conversion calculators on the web that can approximate the LRV from two sets of L a b values, but they are quite subjective. I am trying to 'prove' our contrast materials meet the OSHA/ADA requirements for public access stairs, and relying on some approximate calculator is not really what I was after, (but its in my budget!!)

 

Never mind - I missed the contrast issue and was thinking color matching.