SBS vs CRB vs CUK Paperboard: How to Choose

Start with the job, not the acronym

SBS, CRB and CUK are broad paperboard families, not a complete specification. A useful brief states what the carton must do: protect the product, carry the brand, fit the retail or ecommerce channel, meet any food-contact or labeling review, and run through the converter's equipment. The board name is only one line in that brief.

Write down the product weight, carton dimensions, packing method, distribution route, expected humidity exposure, shelf or storage conditions, print coverage, special colors, barcode needs and any sustainability claim you want to make. If the product needs child resistance or another regulated performance claim, treat that as a separate design and review track. Do not assume a board swap delivers it.

Then ask for board swatches and grade data sheets. A converter can tell you which grades they run well, what caliper they recommend for the carton style, and what proofing route they want. That conversation is more useful than choosing a grade from a name alone.

• Product weight, dimensions and packing method
• Retail, ecommerce or mixed distribution
• Humidity, abrasion and handling risks
• Print coverage, spot colors and barcode placement
• Food-contact or other regulatory review needs
• Recycled-content or material-claim wording you want to use

What SBS, CRB and CUK usually signal in a carton brief

SBS means solid bleached sulfate board. Use that family name as a starting point, not a complete specification. Ask for the exact grade's fiber and coating description, face and edge samples, and any food-contact documentation needed for the intended use. The cited sources address prepress, not SBS grade properties.

CRB means coated recycled board. Ask the supplier to document recycled content for the exact grade and provide face, reverse and edge samples. Compare project-specific costs rather than assuming a price advantage. Ask the converter for strength data, print trials, intended-use food-contact documentation where needed, and a runnability assessment. The cited sources do not establish CRB grade properties.

CUK means coated unbleached kraft board. Ask for the exact grade's construction and coating description, plus face, reverse and edge samples. If a brown edge is part of the design brief, approve a physical sample rather than relying on the family name. Confirm print response and strength data before selecting the grade. The cited sources do not establish CUK grade properties.

• Ask for face shade, reverse shade and edge color samples
• Ask for caliper, grammage and coating details
• Ask for strength and runnability data for your carton style
• Ask for a food-contact statement if the carton touches food
• Ask how the board behaves after scoring and folding

Match the board to the product and the channel

A bright retail carton and a heavy ecommerce pack do not place the same demands on board. Start with the load case: how the carton is filled, closed, packed, shipped and opened. Then ask the converter which board grades and calipers they would sample for that case. Keep the answer in writing so the quote and the artwork brief refer to the same grade.

Ask which material and finished-carton tests are relevant to the proposed structure and distribution route. Compare results only with their test methods, units and conditions identified; a value for one grade does not establish another grade's performance. If comparing corrugated shipping packaging as well, do not convert ECT to Mullen burst strength. Ask whether a structural sample or pack test is appropriate.

If the carton will sit in a humid environment, say so early. If it will rub against a rough surface, say so. If the product is oily or abrasive, say so. These details affect coating, board choice and carton structure more than a generic preference for one acronym.

Print and color checks that change with board shade

Board shade and coating affect how ink looks. A color approved on a white proofing stock may not match the same ink on a darker recycled or kraft face. Ask for a proof on the actual board, or the closest production stock the converter uses, before you approve a brand color. Treat the proof as a decision tool, not a guarantee that every production sheet will match under every light.

Use a PDF workflow agreed with the converter. Adobe notes that industry groups such as the Ghent PDF Workgroup recommend PDF and PDF/X for exchanging packaging jobs, but the converter's workflow still governs the file. Do not assume RGB is banned; PDF/X-4 can carry color-managed RGB, and the agreed conversion route determines what happens next. Ask the converter how they want RGB, spot colors, rich black, printer marks and dieline layers handled.

Output Preview in Acrobat can simulate separations and color warnings, but Adobe notes that onscreen preview does not show trapping, printer marks, halftone screens or resolution. Those items are verified with the print service provider using proofs. Keep registration black distinct from rich black in your artwork notes, and confirm any named spot color against the converter's ink or digital simulation route.

• Proof brand colors on the actual board or closest production stock
• Confirm how spot colors will be simulated or printed
• Keep registration black and rich black clearly labeled
• Ask whether printer marks and dielines belong in a separate layer
• Confirm the proof type the converter will supply

A simplified area and weight estimate

This is a hypothetical arithmetic planning example, not a manufacturable dieline and not a quote. Suppose a simplified open-ended rectangular sleeve, which has no tuck or closure flaps, has two face panels of 90 mm by 180 mm, two side panels of 40 mm by 180 mm and one glue tab of 15 mm by 180 mm. Ignore scores, bleed, trim waste, thumb notches and any tab taper. The flat area is two times 90 times 180, plus two times 40 times 180, plus 15 times 180. That equals 32,400 plus 14,400 plus 2,700, or 49,500 square millimeters. Divide by 1,000,000 to get 0.0495 square meters per sleeve.

Now suppose the hypothetical board grammage is 300 grams per square meter. The net board mass per sleeve is 0.0495 times 300, or 14.85 grams. For planning only, add 12 percent of that net mass as a material allowance: 14.85 times 1.12 equals 16.632 grams allocated per sleeve ordered. For 10,000 sleeves, that is 166,320 grams, or 166.32 kilograms of allocated board. This is not finished sleeve weight or a 12 percent loss rate on gross input. A gross-input loss rate would require dividing net mass by the retained fraction. These hypothetical inputs do not establish actual sheet yield, purchasing quantity or a Teal quote.

Do not turn this area estimate into a die line. Do not assume the flat panel dimensions equal the product dimensions. Do not convert grammage to caliper without the board's density, and do not use weight alone to choose a grade. Ask the converter for a structural sample and a die review.

• Area estimate: 0.0495 square meters per simplified carton
• Illustrative board weight: 300 grams per square meter
• Weight before waste: 14.85 grams per carton
• With an allowance of 12 percent of net mass: 16.632 grams allocated per sleeve ordered
• For 10,000 sleeves: 166.32 kilograms of allocated board, not finished packaging mass

A practical selection checklist

Use this checklist as Teal's editorial planning framework, not as a universal standard. The sources cited below cover specific prepress principles, not paperboard grade selection. Your converter's instructions and your own product testing decide the final specification.

• Write a one-page brief with product, packing, channel and print needs
• Ask for SBS, CRB and CUK swatches in the calipers the converter runs
• Request grade data sheets for caliper, grammage, coating and strength
• Ask for food-contact documentation for the exact grade if needed
• Ask how the board scores, folds and runs on the proposed carton style
• Request a printed proof on actual or closest production stock
• Confirm PDF/X-4 or another agreed PDF workflow with the converter
• Confirm printer marks, dieline layers and page boxes with the converter
• Check registration black versus rich black in the artwork notes
• Ask whether setup, plate, tooling or die fees apply; Teal does not charge setup, plate or tooling fees
• Compare landed cost including waste, freight and minimum order quantity
• Approve a physical sample before committing to a production run

Scope limits and what to confirm with the converter

This guide does not determine food-contact compliance, child resistance, shelf life, distribution testing or legal claims. It does not set a safety threshold or a performance guarantee. Those questions need the converter, the board supplier and the appropriate review process for your product and market.

Board names vary by supplier and region. A grade called CRB from one mill may not match another. Ask for the exact grade code, not just the family name. If your channel has packaging requirements, confirm them in your own supplier agreement or channel documentation. Do not infer a requirement from a general guide.

Teal's standard minimum order quantity is 50 units, with specialty rigid boxes at 100 units where relevant. Ask Teal about sample options for your project. Product prices are quoted per project. Those commercial details do not replace a board and structure review.

Frequently asked questions

These answers are starting points for a converter conversation, not final specifications.

• Can I choose a board by caliper alone? No. Caliper is one input. Ask for grammage, coating, fiber, strength data, print response and food-contact documentation for the exact grade.
• Is CRB cheaper than SBS? Not necessarily. Compare landed cost, waste, runnability, proofing needs, minimum order quantity and freight. Do not assume a sheet price difference decides the project.
• Can I reuse the same artwork on SBS, CRB and CUK? Possibly, after the converter confirms that the dieline, caliper allowances and prepress setup remain suitable. Proof colors on the proposed stock and agree on spot-color handling, rich black and any required barcode verification; a visual proof alone does not verify a barcode.

Questions about Paperboard grade selection for folding cartons