Awards & Engraving

October '18

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Page 59 of 84

A&E OCTOBER 2018 • 57 Sandcarving This is true for all photoresist films, no exceptions. Once you get to this point, you need to refer to the user guide of your spe- cific photoresist to determine the exposure time. Make sure you pick the right exposure time for the thickness of film you are pro- cessing or again, you will not be successful, which brings me back to the main topic: problems you may encounter. EXPOSURE PROBLEM ONE: OVEREXPOSURE I mentioned above that you need to pick the right exposure time for the product you are using, no matter if you are using a washout film or a dry-process film; those guidelines are there for a reason. I strongly suggest not relying on the timer on the Letralite as it often turns out to be inaccurate. It is best to use a digital timer, which greatly increases your chances of producing good exposures time after time. For all of you who tend to fudge a bit when setting the time, you most likely have seen the effects of overexposure. What does that look like? When pro- cessing a washout film, you begin washing the film with warm water and the image starts to appear. Now, you know that you need to keep washing the image until the once-white areas of the film eventually become clear; in a case of overexposure, that will never happen, no matter how long you wash the film. With the dry-pro- cess film, the overall image is much bluer/ purple and hardly has any light green areas left. So, what happened? Why does more time harm the process? The exposure unit covered with the black blanket to achieve optimum contact between artwork and film, as well as block the light from you. IMAGE COURTESY RUTH DOBBINS Washing out the photoresist film with warm water under yellow light conditions. IMAGE COURTESY RUTH DOBBINS

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