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I tried using my Minolta to darken and actually, I think it looks pretty good. Got all the traces nice and black and didn’t lose any of the drill holes. So now I’m wondering – is the Minolta’s toner usable for transfer purposes?
Unfortunately as far as the original goes that is crazy stupid rare unobtanium. The artwork was not offered as part of the Radio Electronics magazine article. You had to write in to ask for the ‘construction guide’ and that’s where they were included. Probably not more than a thousand of those went out 40 years ago and I’ve never seen one for sale anywhere. Long gone. I got this from Michael Holley’s site.. and I doubt he’d loan me his or re-scan it (he doesn’t respond to emails anyway).
So I guess I just have to do what I can with what is available. I’m grateful Mr. Holley did endeavor to put these up back in the day. The project would be impossible otherwise!
From: Homebrew_PCBs@yahoogroups.com [mailto:Homebrew_PCBs@yahoogroups.com]
Sent: Thursday, March 31, 2016 11:47 AM
To: Homebrew_PCBs@yahoogroups.com
Subject: Re: [Homebrew_PCBs] Got some single side boards
You might be able to darken the blacks by scanning as a B & W (not gray scale) with the contrast turned up, and maybe the brightness turned down. A bit of experimentation will be required.
As for scaling, I find that the pdf files I download from Elektor, and others usually print out slightly off dimension. I play around with the scaling on the Adobe reader print function to get it as close as possible. The error is usually in the 1-3% range. The scanning I mentioned above might also have a small effect on the scaling. This gets compensated for at the same time. I also have seen where I have correct the dimension in the X direction, but the Y is slightly off. You can try the scanning again, but with the original rotated 90 degrees. If you have another printer available, you could try that. Otherwise, make the best compromise between the two.
(Another) Harvey
On 3/31/2016 10:28 AM, unclefalter@... [Homebrew_PCBs] wrote:
Picked up a bunch of these on ebay. Thought before I spend $400 I might as well see what I get with these and do some trial runs.
http://www.ebay.com/itm/361162323034?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT
I have a couple questions. I want to use, if possible, the original artwork provided to builders in 1973. Here is a sample of the mainframe artwork that I posted before:
http://www.swtpc.com/mholley/TV_Typewriter/page_18.pdf
This is literally all I have to work with, since an original copy of the artwork is impossible to get now. So questions:
1. Is it dark enough to be usable?
2. If not, what would be the best way to get it darker without altering it too much? I tried just ‘paint bucketing’ black onto it in Photoshop but it seeks out the less visible grey tones and ‘thickens’ the traces, and sometimes obliterates the drill holes.
3. I’m assuming using the toner transfer method I need to print the image in reverse? I assume this image was intended to be used with the presensitized boards, thus it would be printed on clear overhead film and laid on top for exposure.
4. What would be the best way to get it to print at the correct scale. On other artwork I’ve seen actual scales (or ruler edges) displayed. For some reason that is not done here. I guess these would have been printed on standard 8.5x11 pages or something as life size. But because these were scanned from pages of a magazine it’s not quite exact (I printed and compared to my ICs). I guess I could just scale it up a percent or so at a time, but I’m thinking there must be a more scientific way.
5. Anything else to consider?
Thanks guys!!