Custom Colour Matching for Filing Products: Pantone, CMYK and Lab Dip

Why colour matching is harder than it looks

Two folders can use the same pigment name and still look different under office lighting. The reasons are the base resin, the thickness of the material, the surface finish and the lighting itself. A colour that looks correct on a glossy PVC sample can look dull on a matte PP sheet. A shade that matches in daylight can shift under fluorescent tubes. For a private-label stationery range, these differences matter because the customer is comparing the product against a brand colour or against a previous shipment.

At ZOKABS we run custom-colour orders for distributors who need their filing products to match corporate colours or seasonal ranges. This guide explains the three main ways to specify colour, what each method is good for, and how to keep batches consistent from first sample to repeat order.

Pantone references for solid colours

Pantone is the most common reference for solid colours on plastic and paper filing products. A buyer supplies a Pantone C or U code, and the factory mixes a masterbatch to match. The C series is for coated stock and usually gives a cleaner, brighter match on glossy surfaces. The U series is for uncoated stock and is closer to how matte PP or paperboard will look. For office filing products we usually work with Pantone C references because most covers have some gloss.

Pantone matching is not exact on every material. The same Pantone 185 C can look slightly different on PVC, PP and paperboard because each substrate reflects light differently. We always make a lab dip sample on the actual material and ask the buyer to approve it before production. Approving a colour from a screen image or a paper swatch usually leads to a mismatch.

CMYK printing and process colour limits

CMYK is used for printed designs, photographs and multi-colour logos. It works by layering cyan, magenta, yellow and black inks. The problem is that CMYK cannot reproduce every Pantone colour. Bright oranges, deep blues and metallic tones are especially hard. When a buyer wants a printed folder to match a Pantone brand colour, we often add a fifth spot colour or recommend converting the Pantone to the closest CMYK build and accepting the shift.

On PP and PVC folders, CMYK is usually printed by screen or UV offset. The ink sits on the surface, so the colour can change if the surface is glossy or textured. UV printing gives a harder finish and better colour saturation than solvent inks, but it can look slightly raised. We decide the print process based on the artwork and the wear the folder will see.

Lab dip samples and batch approval

A lab dip is a small sample of material dyed or compounded to the target colour. It is the final checkpoint before bulk production. We prepare two or three lab dips from slightly different pigment loads and send them to the buyer for visual approval under their normal lighting. The approved sample becomes the colour standard for the order.

The lighting used for approval is important. A colour that matches under daylight may not match under store lighting. We recommend buyers check lab dips in the lighting environment where the product will be sold. If the product goes to multiple markets with different lighting, we may need to settle on a compromise shade that looks acceptable in both.

Keeping batches consistent

Even with an approved standard, colour can drift between batches. Pigment lots, resin lots and processing temperature all have small effects. To control this we keep a retained sample from each approved batch and compare new production against it under a standard light box. We also record the masterbatch recipe so a repeat order can start from the same formula.

For large ranges with many colours, we suggest limiting the palette to a core set of standard colours plus a small number of custom colours. Standard colours are produced more often, so their recipes are stable. Custom colours need more attention and usually require a lab dip for every repeat order.

Texture, finish and how they change colour

A matte finish scatters light and makes colours look softer and lighter. A gloss finish reflects light more directly and makes colours look deeper and darker. The same pigment load can look a full shade different between matte and gloss. When a buyer approves a colour, we note the finish on the sample. Changing from matte to gloss later means revisiting the colour match.

Embossed textures also affect colour appearance. A leather-grain emboss creates tiny shadows that make the colour look darker. A fine sand texture can lighten the appearance. We match colours on the final textured sample, not on a smooth plaque, because texture is part of the visual result.

Common colour problems and how to avoid them

The most common problem is matching across different materials. A buyer orders PP folders, PVC wallets and paper index dividers in the same corporate blue and expects them to look identical. Because each substrate reflects light differently, the same Pantone code will give slightly different results. The solution is to approve a separate lab dip for each material and accept that the match will be close but not exact.

Another frequent issue is metamerism: two samples match under one light source but not under another. This happens when the pigment mixtures are different even though the colour looks the same in daylight. We reduce metamerism by using the same pigment family across batches and by checking lab dips under multiple light sources before approval.

Fading is a concern for files stored near windows. UV stabilisers can be added to PP and PVC masterbatches to slow colour shift, but they add cost. For archival filing products we recommend UV-stable grades if the colour has to stay consistent for many years.

What to specify for a custom colour order

The ideal specification includes a Pantone reference or a physical colour chip, the material and finish, the print process if there is artwork, and the lighting standard for approval. If the order includes a printed design, state whether the colours are CMYK only or whether spot colours are needed. Also confirm how many lab dips are required and whether batch-to-batch tolerance is checked with a retained sample.

We handle custom colour matching for PP and PVC filing products, including lever arch files, ring binders, box files and document wallets. The process starts with a colour target and ends with an approved lab dip before any bulk material is produced. This avoids the cost and delay of reworking a batch that does not match.

Questions buyers ask

Can you match a colour from my previous supplier?

Yes, if you send a physical sample. We cannot guarantee a match from a photograph because cameras and screens change the colour. A physical sample lets us measure it and prepare a lab dip on the correct material.

How close is an acceptable colour match?

Most buyers accept a Delta E of 2 or less for solid colours in normal office lighting. Stricter matches are possible but increase cost because they need more pigment adjustment and tighter process control.

Does colour matching add to lead time?

Allow three to five extra days for lab dip preparation and approval. Once approved, bulk production follows the normal schedule. Repeat orders using the same approved recipe do not usually need new lab dips unless the material or finish changes.