PCBs with a tan...

[Nasse]

Just my two cents:

I have tried photocopy/laser printer to clear overhead projector film. I think they say you can have slightly better results if you print the black stuff so it is against the photosensiticed copper, so the UV light does not go "under the edges". But you may need good craphic software that can print reverse.

I noticed that you can "soak" the black toner with water soluble drawing ink (the black stuff engineers and architects use it in special pens). I just smeared the pattern side of the clear sheet with some ink put on toilet paper, and if you wipe enough the ink goes off the clear area but some of it stays in the toner pattern. The ink is quite expensive and hard to find these days.

If you can not find better alternative for sodium hydroxide, you can find it super cheap in almost every average food shop selling household chemicals. Look for "Plumber´s helper" drain opener or something. But it is dangerous for your eyes and skin. Good sodium hydroxide stuff.

You can fix mistakes and pinholes with fine point permanent marker again after developing, before etching.

But I believe if I make another PCB some day (have plans to do so maybe next weekend but the pattern needs some retouching) I´ll try that laser printer or photocopy machine to inkjet photo paper method

[markusw]

Just my two cents:

I think they say you can have slightly better results if you print the black stuff so it is against the photosensiticed copper, so the UV light does not go "under the edges".

Thats the way I do it but I am not really sure if there is any benefit, especially since I am using two copies. So light might creep under the edges of the upper copy.Anyway, at least the lower copy´s toner is in derect contact with the surface of the board.

I noticed that you can "soak" the black toner with water soluble drawing ink (the black stuff engineers and architects use it in special pens). I just smeared the pattern side of the clear sheet with some ink put on toilet paper, and if you wipe enough the ink goes off the clear area but some of it stays in the toner pattern.

Sounds interesting. Is it called indian ink??

[Nasse]

I have seen sometimes it reads "China Black" or something on the bottle. I used it in the Rotring Rapidograph and similar capillar tube pens.

Now I have a small bottle of Rotring stuff but I have used "Higgins Black Magig" http://www.discountart.com/store/higgins-drawing-ink.html