簡易樹脂版縮邊計算公式 |
當樹脂版被貼在圓形的版輥上時，版面上的影像會向圓形四周放射，因此其影像將比較版材平放時些微伸長，而其延伸比例與版輥直徑及版材厚度有密切關係。
如果我們採用與版輥同樣直徑的圓晒製版機，它將沒有影像延伸問題，亦即您的印刷成品將與底片影像大小是吻合的。但是您有多少支不同圓周尺寸的版輥，您得準備多少支不同圓周的“圓晒製版滾筒”，且每次做不同圓周的製版必須更換晒版滾筒，不但不方便且費時費力，儲放圓晒版輥亦浪費空間確時不經濟。
因此大部分業者採用平面晒版，此時應注意版面的圖像掛上版輥，其印刷出的圖形與印刷方向相同的影像會比底片影像稍微增長，例如底片上的正方形會變長方形、圓形會變橢圓形，因此我們必須做底片的縮邊。
| 縮邊比例 % ＝ 1 － (版材延伸係數 × 100 ÷ 版輥圓周長) ÷ 100 |
|---|
| 版厚 | 係數 | 圓 週 | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| 340 | 360 | 400 | 480 | 500 | 540 | 560 | 580 | 600 | ||
| 0.76 | 4.30 | 98.74% | 98.81% | 98.93% | 99.10% | 99.14% | 99.20% | 99.23% | 99.26% | 99.28% |
| 1.14 | 6.20 | 98.18% | 98.28% | 98.45% | 98.71% | 98.76% | 98.85% | 98.89% | 98.93% | 98.97% |
| 1.70 | 9.90 | 97.09% | 97.25% | 97.53% | 97.94% | 98.02% | 98.17% | 98.23% | 98.29% | 98.35% |
| 2.30 | 13.60 | 96.00% | 96.22% | 96.60% | 97.17% | 97.28% | 97.48% | 97.57% | 97.66% | 97.73% |
| 2.54 | 15.14 | 95.55% | 95.79% | 96.22% | 96.85% | 96.97% | 97.20% | 97.30% | 97.39% | 97.48% |
| 2.72 | 16.45 | 95.16% | 95.43% | 95.89% | 96.57% | 96.71% | 96.95% | 97.06% | 97.16% | 97.26% |
| 2.84 | 17.09 | 94.97% | 95.25% | 95.73% | 96.44% | 96.58% | 96.84% | 96.95% | 97.05% | 97.15% |
| 3.18 | 19.15 | 94.37% | 94.68% | 95.21% | 96.01% | 96.17% | 96.45% | 96.58% | 96.70% | 96.81% |
| 3.94 | 23.94 | 92.96% | 93.35% | 94.02% | 95.01% | 95.21% | 95.57% | 95.73% | 95.87% | 96.01% |
| 4.32 | 26.34 | 92.25% | 92.68% | 93.42% | 94.51% | 94.73% | 95.12% | 95.30% | 95.46% | 95.61% |
| 4.70 | 28.70 | 91.56% | 92.03% | 92.83% | 94.02% | 94.26% | 94.69% | 94.88% | 95.05% | 95.22% |
| 5.00 | 30.60 | 91.00% | 91.50% | 92.35% | 93.63% | 93.88% | 94.33% | 94.54% | 94.72% | 94.90% |
| 5.50 | 33.74 | 90.08% | 90.63% | 91.57% | 92.97% | 93.25% | 93.75% | 93.98% | 94.18% | 94.38% |
| 6.00 | 36.60 | 89.24% | 89.83% | 90.85% | 92.38% | 92.68% | 93.22% | 93.46% | 93.69% | 93.90% |
| 6.35 | 39.08 | 88.51% | 89.14% | 90.23% | 91.86% | 92.18% | 92.76% | 93.02% | 93.26% | 93.49% |
| (以上公式及表格僅適用於德國 BASF 版材) | ||||||||||