Addenda: Jeff Heiss in the "photoresist application" thread mentioned the site which recommended leaving the polyester sheet in place for a while after exposure: "Note that the dry film resist should be exposed with the cover sheets on, and then held in a dark place for 15 minutes before removing the cover sheets and developing." http://www.electro-tech-online.com/general-electronics-chat/14427-photoresist-pcb-etching-process.html This was from 2005, quoting extensive Riston 4713 instructions by Jon Elson: http://pico-systems.com/PCBs.html I recall reading this instruction somewhere else, but not in DuPont material. - Robin http://www.firstpr.com.au/pcb-diy/
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Re: [Homebrew_PCBs] Patent, storage & other info - Riston & negative dry film photoresists in general
2013-01-14 by Robin Whittle