k7elp60

[QUOTE=

Many people have tried to use the overhead transparency sheets as a mask for making printed circuit boards and silkscreens. Virtually always with poor to marginal results. That black toner on the clear background looks nice and dense but, the toner is actually quite transparent and lets a lot of the light through to expose parts of the photoresist or emulsion that are supposed to be masked.

I disagree with you, I have been using transparancies and an EPSON R200 inkjet printer to make artwork for PCBs for a number of years. I use the transparancies on positive sensitized boards that I expose, develope and etch. I have been doing this for over 4 years. I consistantly do trace widths of .020" all the time.

Do an search on the internet for transparancies at several national office supply stores showes many supplies

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crashsite

Yep, guys...the times they are a-changing. "They" keep forcing us to upgrade to not only better but, cheaper technologies.

I have no doubt that the day is coming when some variation of the, Lightscribe technique, used on some of the new, recordable DVDs, will become available to experimenters as a way to apply patterns to circuit boards (or what will pass for PCBs...which may be home versions of ICs). In the meanwhile we chug along with materials at hand.

crashsite

Today this is true. In a few years if may not be. I believe that the prudent experimenter will stock up on the transparency film.

This is veering from the topic a bit but, here in town they are tearing down an old livestock auction yard and I have been taking some photos and video of the demolition with the idea of submitting them to the local historical society. I am already wondering what format and/or media I should use that can actually be read in another 20, 50 or 100 years.

jpanhalt

You mean like all of that archival material on VCR tape and 5.25 floppies?

Have you considered a silver-based photograph? There are also dye-based prints that are supposed to be long lasting. With the rate of change in technology, the term, "back to the future" might apply to anything you want to archive for even 10 years. That is, if you want it to be accessible in the future, go back to a technology that we know works.

John

crashsite

Yes.

In my (perhaps not so) humble opinion, the transfer of this data should already be taking place (especially from tape-based technologies but, also early disk media). Doing this should be part of high school and perhaps even higher grade school class and extra credit projects. But, for all the stroking and accolates, educators are among the least forward-looking people in the population. Personally, I attribute a lot of it to the strong unionization of the school system but, I digress.

We are entering a phase where substantially massive amounts of data can be stored on simple media (I'll most likely use 3 DVD-Rs for my auction yard photos and video clips since Blu-Ray is still too new and expensive). By having the data concentrated it will be relatively easy to bulk transfer it to new media as new storage devices come on line. I envision the end-point of that process to be data storage directly into a crystal matrix at the molecular level with the read and write functions implemented with X-ray lasers. But, that's a project for a different thread in this, electronic projects topic area....several years from now.

What we have here and now is the most awkward phase. The physical stuff (photos and documents and artifacts) is not too much of a problem. It's been around a long time and, properly stored, can remian even longer. Data stored electronically (on tape and already obsolete disk media), that needs to be transcribed, is the problem. As you so correctly point out, they need readers that are already getting difficult to come by and which often have chips, rubber and plastic parts and electrolytes which can deteriorate and fail, making them unusable in the upcoming decades and centuries.

So, the task is not being done now and can't be done later and there doesn't seem to be anybody at the helm who is even thinking about it.

Hero999

I've always used tracing paper and found it superiour to transparencies so this makes no difference to me.

Am I the only person who has tried this?

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mike50

Yes, I've used tracing paper too. It worked fine for me, although I needed to use a longer exposure time.

Mike

Hero999

I imagine that that's probably true but I didn't really notice a large difference.

The thing I like about tracing paper is that it doesn't matter if the toner isn't that thick and you can it's easier to shade in the missing parts with a fine pencil, than it is to colour a transparency with a permanent marker.

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crashsite

I've used tracing paper and vellum and have fouind the toner just not dense enough to provide the contrast for good, consistent results. I've also used vellum as a "release" agent for the "toner as the resist" method and have even used tracing paper for that method with no mechanical lifting of the paper (disolving the paper away with suphuric acid). But, do note that not all brands of tracing paper are the same. Some are akin to vellum and others more like very thin paper.

But, even with the paper, it surely wouldn't hurt to beef up the density of the layout by overlaying the foil.