Colour on polypropylene filter board is more constrained than people expect, and the constraint is economic rather than technical. Almost any colour can be produced; producing it in a short run costs disproportionately more. Knowing where the line sits lets you specify colour sensibly.
Why short runs cost more
Colour is compounded into the material, and a production run has to be brought onto shade. The material produced while that happens is off-colour and gets scrapped or reworked. On a long run that waste is a small fraction; on a short run it can be a large one.
This is why a minimum quantity often applies to a custom shade and not to a standard one. It is not a markup; it is the setup waste being spread over fewer metres.
What to specify, and what to leave out
If the colour is identification – this panel goes in that stage – a near match is completely adequate and a standard shade will usually do. Say that it is identification only, and the range available opens up considerably.
If the colour is part of a product’s appearance, or has to match an existing panel on a machine, then it is functional and needs specifying properly: a reference sample retained on both sides, a stated lighting condition for judging, and agreement on what happens if a batch misses.
Batch-to-batch consistency
Worth asking about explicitly if colour matters. Two panels from different batches under different light can differ; under a warehouse light they may look identical and outside they may not. Agree where they will be judged.
Retaining a reference sample on both sides is the single cheapest control. It settles arguments in a way that no correspondence does.
Lighting and metamerism
Two panels can match under one light and not under another, because the pigments reflect differently across the spectrum. This is not a defect and it is not rare – it is why colour should always be judged under a stated lighting condition.
Daylight is the honest condition for anything that will be seen outdoors or near a window. Warehouse lighting is the honest condition for anything that will only ever be seen inside. Agree which before approving a shade, and the later argument disappears.
Recycled content and colour
Recycled polypropylene carries colour from its previous life, which limits how light or how clean a shade can be made and introduces variation between batches. Where colour matters, virgin material gives more control; where it does not, recycled is often perfectly serviceable and cheaper.
The point is to know which you are getting. Colour variation that arrives unexpectedly looks like a quality problem; the same variation declared in advance is a specification choice.
Specifying what happens on a miss
This is the clause people forget. If a batch arrives and the colour is outside what you accept, what happens – replacement, credit, or acceptance at a lower price? Agreeing it before the first order turns a future argument into a process.
Set the acceptance band in words rather than numbers where possible: “matches the reference sample under daylight at arm’s length” is workable and testable. A numeric colour difference is precise and requires an instrument most people do not have.
What we can do
We supply custom colour PP honeycomb filter board and will tell you whether your requirement needs a custom shade or whether a standard one will serve. Tell us what the colour is for – identification or appearance – and we will quote accordingly.