以PNP紙（press-n-peel blue transfer film）為保護層，進行金屬表面質地效果處理的蝕刻法，除了官方網站有詳細的使用方法介紹之外，在網路上也有許多金工創作者的P N P paper心得分享。
這裡寫的是稍微特殊一點的使用經驗。
I have been checking the internet and trying to find if there is a possibility that I could transfer PNP image onto a curved surface. I have found nothing, but I have to have it - both the chance and the surface. The piece I am working on needs plenty of forging. If I etch→forge the piece, the patterns and textures would be changed, maybe even flattened or gone; if I forge→etch the piece, which is what I have done, I would have to find the answer to the question: how to transfer a PNP image onto a curved surface?
Therefore, I did some tests.
一般來說，PNP paper只能用於平坦的金屬表面上，因為它需要熱、壓才能有好品質的轉印，所以任何無法與PNP paper貼服的部份，都可能影響蝕刻圖案的效果。目前正在製作ing的此物件，我需要的圖案只能使用PNP paper進行轉印，才能滿足精細度的需求。然而先將圖案轉印到金屬上，在腐蝕之後再進行塑形，蝕刻的圖案很可能會在鍛敲的過程中扭曲變形，甚至凹陷；反之，如果各大小零件的形狀、尺寸、嵌接都定型之後才進行蝕刻，我要面臨的就是「PNP paper的圖案能否被轉印到彎曲的金屬表面上呢？」這個問題了。
Certainly I started with a clothes iron. Although the metal sheets were forged to metal bands, they still have smooth surfaces and the PNP papers seemed to be placed nicely on the surfaces.
首先試老方法：熨燙。雖然金屬片已經變成金屬圈，但是表面還算平整，於是我抓著剩下的一絲希望，拿出熨斗。然而，無論我將熨燙的溫度設定在適溫或是高於適溫，都無法將圖案漂亮地轉印到金屬表面。接觸面積不夠，壓力就不夠，溫度更不夠。圖案支離破碎，效果不優。
However, the contact areas were far too small so the pressure and temperature were not enough and even, therefore, the images were not successfully transferred. The result was bad.
Then, I thought of using a hair dryer.
接著試吹風機。轉印PNP paper的熱源必須是乾熱，加熱的時候遇上的液體或水汽都可能毁壞圖案。有熱源也要有壓力，我用的是不鏽鋼尺－的尺面（不能用尺緣，否則刮破膠膜又損壞圖案就......）。不過，即使把吹風機放在再怎麼樣近的距離加熱，溫度還是太低；人工手施的壓力也太不穩定，加上接觸面積仍然太小，效果更差。
The result was even worse. The temperature and pressure were too low and weak, and not stable either: I applied the pressure with a steel ruler (flat side), and it caused the friction.
There are people using rub-on transfer stickers for the protection.... I did consider to order custom-made rub-on transfer stickers, and I made phone calls to the companies.... no way, they are ink-based images.... .
就在我開始考慮是否應該訂製轉印貼紙的時候，突然靈光一現：烤箱！如果我能將PNP paper緊密覆蓋在金屬表面送進烤箱加熱，是否會成功呢？
Ha, OVEN!
I placed the PNP images on the surfaces and fixed them with masking tape for the first try, and the result was.... not too bad, no burning masking tape, and the images were transferred quite nicely. But the masking tape stuck to the metal and left stains, which couldn't be removed by scratching - the transferred images would be off either.
一開始我用紙膠帶固定PNP paper。紙膠帶雖然不會燒起來，但是會烤得脆脆硬硬地，巴在金屬表面，要摳摳摳。一陣翻箱倒櫃，我翻出一卷磁鐵帶。PNP paper定位，拉緊，頭尾用磁鐵帶覆蓋、壓緊（並非為了磁性，是為貼服與加壓的效果），用金屬夾固定，送進烤箱，以200℃的溫度加熱......最少二十分鐘。件數增加，溫度也要拉長（比較保險）。
I found a magnetic tape. I placed the PNP images on the surfaces again, and covered them with the magnetic tape (for the protection, not the attraction), then hold them with metal clips. The oven temperature was set to 200℃ and baked for at least 20 minutes (longer time if more pieces), and it came out....
結果......
Hurray!!：D
It might be working too with baking paper + binding wire. I presume.
ps. Do not quench the whole piece after baking, otherwise the PNP film could become crispy and crack up when peeling, which would cause more problems. Just leave it and let cool.
後來我又想到，如果用烘焙紙包覆＋金屬絲纏繞綁PNP paper，應該也有機會。
另外，加熱完畢取出之後，請勿將物件入水想急速降溫，PNP paper的膠膜會脆化，然後巴在金屬表面......摳摳摳......轉印圖案就一起摳掉。請讓它們自然降溫。謝謝。
