Barcodes and Laminates: A Challenging Relationship
Barcodes and laminates are like an arranged marriage. There is little natural initial affinity for each other but someone else has decided they will be together. With effort and adjustments, it can succeed. It takes diligence and openness to learning.
Like all relationships, there are attributes that can make it challenging. Here is a short list:
- 1D barcodes are more likely to have problems than 2D symbologies
- Smaller X dimensions – generally 10 mil is the minimum but larger X dimensions can also be problematic
- Longer 1D barcodes with lots of encoded data
- Binary barcodes with smaller wide-to-narrow ratios
The laminate itself can cause scanning problems but the above attributes are a significant factor. Here’s why:
–1D barcodes use elements (bars and spaces) of various widths to encode the data. With elements of varying widths, there could be a range of reflective variations to detect. 2D symbologies use a single element width or X dimension. Ideally, there are only two reflective values to detect.
–the width of smaller X dimensions are more likely to degrade due to printing inaccuracies and by the optical properties of the laminate that can make bar and space edges unsharp.
–a 1D barcode encoding a large amount of data will long; the scanner will see the edges at a different angle than the center. The optical influence of a laminate will be greater at the edges than at the center.
–it is more difficult to distinguish the element widths of a binary 1D barcodes (those with just two element widths) where the wide-to-narrow ratio is small.
Data encoded in a barcode is decoded by detecting the reflectance differences between the light and dark elements. Anything that degrades that critical difference can cause lower verification grades and scanning problems.
Apply sound scientific technique when sorting out a scanning problem involving laminate. Avoid jumping to conclusions based on pre-conceived beliefs—lamination is not always the problem. If your laminated barcodes are grading poorly, test the pre-laminated barcodes before concluding that lamination is the problem. When printing multiple repeats across the web and around the cylinder, take the time to verify every barcode; proceed based on facts, not conviction. Lamination can never improve a bad barcode.
Make use of the verification report to determine if gain is already a factor, which is aggravated by the laminate. Note which ISO parameters are downgrading the pre-laminated barcode. Correct problems here before blaming the laminate and pursuing a solution to the wrong problem.
If lamination is determined to be the problem, explore alternative laminates with your provider. Use the verification report to describe the specific problem the laminate is causing.
If an alternative laminate does not solve the problem, here are avenues to consider:
- With 1D barcodes, use a larger X dimension and a larger wide-to-narrow ratio if it is a binary barcode like ITF or Code 39
- Minimize the amount of data (if your trading partners agree) to shorten the 1D barcode
- Replace the 1D barcode with a 2D symbology such as Datamatrix
The verification report can be the key to detecting barcode problems and validating a solution, but do not overlook the value of a visual examination of a poorly grading, using a low power magnifier. This can help you understand and explain why the barcodes is failing, and make the process of finding the right solution efficient and effective.