Photopolymer Mysteries: Who Needs Base Thickness Anyway?

Almost everyone knows the height of a photopolymer. Each industry has its recommended standard, but few know the base thickness—and even fewer understand its importance. Measuring it? Of course not! Why bother?

If nobody mentions it, everyone’s happy.

Now, if you struggle with dot gain or uneven solid areas when switching between photopolymers—especially around barcodes or fine edges—this might be the culprit. Tweaking the pressure? That only shifts the problem to the image, and increasing it will just bring new defects you hadn’t noticed before.

But wait, there’s more! The dimensional stability of the dot, the plate’s lifespan, and the PET adhesion are also at stake.

What’s the right height?

There isn’t one perfect answer. What truly matters is minimizing variation both within and between plates. But if you insist, I usually recommend keeping the base thickness at around 70% of the total plate height.

What’s an acceptable variation?

Let’s say the base is 70% of the total height: for a 1.14 mm plate, the base would be 0.80 mm. A variation of ±0.02 mm is reasonable.

Did this help? Maybe even a like wouldn’t be too much to ask… Or is that pushing it?

Enjoy your day!