OK thank you for these clarifications. Here goes our trek into the land of "It depends:"
1) 7.5.3 states the organization shall identify the product status by suitable means throughout Product Realization.
The clause goes further in stating "Where traceability is a requirement, the organization shall control the unique identification of the product and maintain records." This clause relies on the need to identify product status having been stated by someone; since ISO 9001:2008 does not specifically prescribe the requirement, logically the requirement's specification should come from you or your customer.
2) 7.5.4 refers to customer supplied property. I failed to ask if this paint is supplied by the customer for your processing. If it is, this clause says we will safeguard that property, which means identify and verify and protect. "Identify" arguably means status as well as identity.
3) 7.5.5 refers to preservation, and it specifies identification as well as handling and storage & protection.
These traceability clauses strongly infer that product and its status is controlled and identifiable. That doesn't mean we have to put it in a vault and prop a flashing billboard by the stuff; we should do that which is appropriate for our processes. Systems that have a barcode stuck to each item and a computer software application that tracks each item's identity and status will arguably not need to be otherwise identified if that barcode must be scanned when introducing the material into the production stream.
What I am trying to say is that means of identification vary, and the standard gives us some freedom to define what that identification is to be, based on the process flow and control plan.
The means to identify then become the subject. If this material was routinely (and as defined by written procedure) set aside in a clearly marked and wholly segregated place (some people use a locked "cage") and the process flow plainly showed its movement to a "ready to use" status included being physically moved to another specified location, one might argue that individual markings are not needed. The argument becomes one of overall identification schemes and reliable, procedurally set control.
So, having established that identification is required, what we're dealing with is details: how you have developed and maintained a system that is defensible by design and empirical results (no accidental introduction of inadequate material that, as it turns out, should have been in evaluation status).
Does this make sense? I'm afraid my response was awfully wordy.
