Photo Resist Etching

Etching is a process we learn’t just before christmas. It is a process of acid attacking and eating away copper. Ferric Chloride acid is used in a tank with an air pump to etch away the metal. This is a very long and time consuming process.

To start off i needed some copper sheet blanks and some images which i would use to create the etching pattern. The images that are successful within photo resist etching are those with a strong black and white contrast and those which almost have a strong illustration feel to them. I learnt that abstract images don’t work that well.

After cleaning, sanding and de-greasing my copper plates i had to then prepare them with a photosensitive film. This is the lamination stage and it is done in the dark room. I is recommended to leave the laminated plates over night to get a thorough bond between the metal and film. The following day i could them print my positive images onto a clear film. This is used with UV light to transfer the image onto the pre bonded film. You could print onto acetone as a cheaper option.


This is our images ready to be exposed to the UV light. This UV light exposure machine has a vacuum so that the plates and images will get the best, closest exposure possible.

Once the plates have been exposed they can then be developed.



These are the instructions for creating the developing solution.

After developing and drying the plates they now need to be exposed again to harden.


Once hardened you are nearly ready to put the plates into the acid! hooray!


At this part of the process you can use a ‘stop out’ by using a acrylic resist. You paint this liquid straight onto the plate. This technique stops the acid from etching into parts of the copper that you do not want to be etched. From this part of the process i learnt that you could directly paint onto the de-greased copper plate and then etch out the rest. Useful to know for more abstract patterns and lots quicker!



After this has dried i then prepared the back of my plate for etching. To protect the back i used parcel tape to cover it and then used scalpel to cut the plate out. After this a tag needs to be attached to the plate so that it can be hung into the acid from a rack.




The tags are attached to the rack with pegs. This is when the etching happens and when you turn the air pump on to speed up the process. fullsizerender-9

The longer you leave the metal in the acid the deeper the etch will be. Mine was in for about 2 hours and it hadn’t etched a millimetre deep. You need to check in intervals and it was not recommended to leave overnight as there could be a change of creating holes in the copper.


Overall i enjoyed learning a new technique however i don’t think i would use this process again as it was too time consuming for the outcome i really wanted. Next time i would paint directly onto the copper to create abstract patterns and textures.


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