Haven't pulled the trigger on my first attempt to make a pcb using the photo-resist method. Here is my setup.

Created the board layout in Eagle (free version) Purchased photo-resist from ebay - seems there is no information on the product I bought. Purchased positive developer from MG Chemical

My first attempt seemed to indicate that the layout transparency needs to be a negative image (traces clear and background black) Is there something I should have done to be able to use positive images?

I made a small exposure box using 180 UV LEDs and it seems to expose the film in about 10 minutes.

Is there a way to get Eagle to print negative images of the payout artwork?

What should I look for in photo-resist and developer if I want to develop from a positive image?

I've seen a few YouTube tutorials that show the exposed photo-resist being developed using sodium carbonate. Is that better or not as good as using MG Chemical positive developer or did I miss understand them entirely?

Is there something I should be using instead? Unfortunately there is so much info on YouTube and the web that is not consistent and hard to figure out who to listen too.

  • \$\begingroup\$ I'm not a MG Chemicals fanboy by any stretch, but their stuff is pretty damn good. \$\endgroup\$ Oct 15, 2016 at 1:11

1 Answer 1


Instead of selecting the layers you want printed from the "displayed layers" list of the editor and using the print tool to produce an image, use the CAM processor. Select the layers you want, and use PS_Inverted as the output "device", which will produce an inverted black and white postscript document.

You can render the postscript file with Acrobat, PS View, InfranView and others. The same applications should allow you to send it directly to a printer as well.

  • \$\begingroup\$ Since OP has an AskUbuntu account, I'd like to add that I've had great success using Inkscape for post-processing postscript output from Eagle. Useful if you want to print multiple boards, or add logos and such. \$\endgroup\$
    – pipe
    Oct 15, 2016 at 7:10
  • \$\begingroup\$ Jams: I will play with that a little later today. I know PS does a better job of maintaining dimensions than most formats, but I haven't used it in years. Stream \$\endgroup\$
    – Charlie RC
    Oct 15, 2016 at 16:36
  • \$\begingroup\$ Pipe: hadn't thought about Inkscape. Good reminder. \$\endgroup\$
    – Charlie RC
    Oct 15, 2016 at 16:37
  • \$\begingroup\$ Ignacio: I've been doing toner transfer for a while using cheap eBay copper clad. I tried MG Chemicals boards and my pcbs took a huge step forward. I guess I've become a "fanboy" for them. \$\endgroup\$
    – Charlie RC
    Oct 15, 2016 at 16:42
  • \$\begingroup\$ JMS: I tried the method you outline above, but the image I got was VERY low res. I viewed the image in PS Viewer and photoshop with the same results. It seems like your image above is higher resolution, but in both your's and my image both have a pattern of lines in the background. I can deal with that, but the resolution makes this unusable. Is there a way to get a higher resolution image, or is there something about my system that might dictate the resolution? \$\endgroup\$
    – Charlie RC
    Oct 18, 2016 at 22:29

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