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Got some single side boards

Got some single side boards

2016-03-31 by unclefalter@...

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!!

 


Re: Got some single side boards

2016-03-31 by unclefalter@...

Oh.. I just discovered I can use my Minolta Di200's (big combo photocopier/printer/scanner) darken feature to photocopy the artwork darker almost perfectly.  Would the Di200's toner be alright for the purposes of etching?

Re: [Homebrew_PCBs] Got some single side boards

2016-03-31 by Harvey White

On 31 Mar 2016 10:28:53 -0700, you 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 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 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:
>
> Is it dark enough to be usable?

I wouldn't be happy with it, no.

> 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.

Change the color palette to monochrome, and then use a very fine brush
to cover the holes, that's one way.


> I’m assuming using the toner transfer method I need to print the image in reverse?

No, the dark area is the toner which is transferred directly. These
are fine.

>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.

Nope, not at all.

Taken down to a photo/graphics shot and converted into a negative on
kodalith film, then printed on KPR sensitized boards.

OR

Same process and use a positive acting system, where you coat the
board completely with resist, print the positive pattern, develop it,
then tin plate the board, remove the resist, then use ammonium
persulfate or something that leaves tin alone and eats copper.

So depends on what you wanted.


> 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.

Take an IC on the board and generate from it a measurement, or use the
board edges as a scale. Then scale it up to the desired size from
that.

> Anything else to consider?

It looks as if the paper when scanned was not completely flat, so that
can be a small problem. If you could find a back issue of the
magazine and then scan from that, it would be a lot better.

Harvey

>
> Thanks guys!!
>
>

Re: [Homebrew_PCBs] Got some single side boards

2016-03-31 by Harvey Altstadter

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!!

 



RE: [Homebrew_PCBs] Got some single side boards

2016-04-01 by Brad

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!!

 

 

 

RE: [Homebrew_PCBs] Got some single side boards

2016-04-01 by Brad

Sorry, what I meant by print the image in reverse is I assume I need to ‘mirror it’.  Unless I’m misunderstanding the process, if I printed it as is on my glossy paper and ironed it to the PCB copper, I’d end up with an image that was backwards.

 

From: Homebrew_PCBs@yahoogroups.com [mailto:Homebrew_PCBs@yahoogroups.com]
Sent: Thursday, March 31, 2016 10:54 AM
To: Homebrew_PCBs@yahoogroups.com
Subject: Re: [Homebrew_PCBs] Got some single side boards

 

 

On 31 Mar 2016 10:28:53 -0700, you 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 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 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:
>
> Is it dark enough to be usable?

I wouldn't be happy with it, no.

> 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.

Change the color palette to monochrome, and then use a very fine brush
to cover the holes, that's one way.

> I’m assuming using the toner transfer method I need to print the image in reverse?

No, the dark area is the toner which is transferred directly. These
are fine.

>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.

Nope, not at all.

Taken down to a photo/graphics shot and converted into a negative on
kodalith film, then printed on KPR sensitized boards.

OR

Same process and use a positive acting system, where you coat the
board completely with resist, print the positive pattern, develop it,
then tin plate the board, remove the resist, then use ammonium
persulfate or something that leaves tin alone and eats copper.

So depends on what you wanted.

> 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.

Take an IC on the board and generate from it a measurement, or use the
board edges as a scale. Then scale it up to the desired size from
that.

> Anything else to consider?

It looks as if the paper when scanned was not completely flat, so that
can be a small problem. If you could find a back issue of the
magazine and then scan from that, it would be a lot better.

Harvey

>
> Thanks guys!!
>
>

Re: [Homebrew_PCBs] Got some single side boards

2016-04-01 by Stefan Trethan

Typically PCBs are designed today "looking through" the top side.
So you would print the bottom side out without mirroring for toner transfer. Even for photoprocess there is the argument made to put the ink on the board side, so the light doesn't stray while going through the transparency.

However there is text on your layout, and it is not mirrored, so yes you must mirror it before printing.

ST

On Fri, Apr 1, 2016 at 6:54 AM, 'Brad' unclefalter@... [Homebrew_PCBs] <Homebrew_PCBs@yahoogroups.com> wrote:


Sorry, what I meant by print the image in reverse is I assume I need to ‘mirror it’.  Unless I’m misunderstanding the process, if I printed it as is on my glossy paper and ironed it to the PCB copper, I’d end up with an image that was backwards.

T

From: Homebrew_PCBs@yahoogroups.com [mailto:Homebrew_PCBs@yahoogroups.com]
Sent: Thursday, March 31, 2016 10:54 AM
To: Homebrew_PCBs@yahoogroups.com
Subject: Re: [Homebrew_PCBs] Got some single sideTypi boards

 

 

On 31 Mar 2016 10:28:53 -0700, you 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 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 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:
>
> Is it dark enough to be usable?

I wouldn't be happy with it, no.

> 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.

Change the color palette to monochrome, and then use a very fine brush
to cover the holes, that's one way.

> I’m assuming using the toner transfer method I need to print the image in reverse?

No, the dark area is the toner which is transferred directly. These
are fine.

>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.

Nope, not at all.

Taken down to a photo/graphics shot and converted into a negative on
kodalith film, then printed on KPR sensitized boards.

OR

Same process and use a positive acting system, where you coat the
board completely with resist, print the positive pattern, develop it,
then tin plate the board, remove the resist, then use ammonium
persulfate or something that leaves tin alone and eats copper.

So depends on what you wanted.

> 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.

Take an IC on the board and generate from it a measurement, or use the
board edges as a scale. Then scale it up to the desired size from
that.

> Anything else to consider?

It looks as if the paper when scanned was not completely flat, so that
can be a small problem. If you could find a back issue of the
magazine and then scan from that, it would be a lot better.

Harvey

>
> Thanks guys!!
>
>




Re: [Homebrew_PCBs] Got some single side boards

2016-04-01 by Harvey White

On Fri, 1 Apr 2016 08:40:19 +0200, you wrote:

>Typically PCBs are designed today "looking through" the top side.
>So you would print the bottom side out without mirroring for toner
>transfer. Even for photoprocess there is the argument made to put the ink
>on the board side, so the light doesn't stray while going through the
>transparency.

For the boards I make, the bottom is not mirrored, the top is. (given
EAGLE). I also rotate the boards long way matching the long side of
the paper. By properly orienting the board (with mirroring when
needed) and rotating if needed, I match identical areas on the board's
top and bottom, giving the same orientation when printing. I figure
that if there is any irregularity across the printer (or up and down),
then having like areas matching will minimize problems with
registration. In eagle, the bottom is generally printed as is, and
the top is generally printed "upside down and mirrored".

Harvey

>
>However there is text on your layout, and it is not mirrored, so yes you
>must mirror it before printing.
>
>ST
>
>On Fri, Apr 1, 2016 at 6:54 AM, 'Brad' unclefalter@... [Homebrew_PCBs]
><Homebrew_PCBs@yahoogroups.com> wrote:
>
>>
>>
>> Sorry, what I meant by print the image in reverse is I assume I need to
>> ‘mirror it’. Unless I’m misunderstanding the process, if I printed it as
>> is on my glossy paper and ironed it to the PCB copper, I’d end up with an
>> image that was backwards.
>>
>> T
>>
>> *From:* Homebrew_PCBs@yahoogroups.com [mailto:
>> Homebrew_PCBs@yahoogroups.com]
>> *Sent:* Thursday, March 31, 2016 10:54 AM
>> *To:* Homebrew_PCBs@yahoogroups.com
>> *Subject:* Re: [Homebrew_PCBs] Got some single sideTypi boards
>>
>>
>>
>>
>>
>> On 31 Mar 2016 10:28:53 -0700, you 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
>> 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
>> 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:
>> >
>> > Is it dark enough to be usable?
>>
>> I wouldn't be happy with it, no.
>>
>> > 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.
>>
>> Change the color palette to monochrome, and then use a very fine brush
>> to cover the holes, that's one way.
>>
>> > I’m assuming using the toner transfer method I need to print the image
>> in reverse?
>>
>> No, the dark area is the toner which is transferred directly. These
>> are fine.
>>
>> >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.
>>
>> Nope, not at all.
>>
>> Taken down to a photo/graphics shot and converted into a negative on
>> kodalith film, then printed on KPR sensitized boards.
>>
>> OR
>>
>> Same process and use a positive acting system, where you coat the
>> board completely with resist, print the positive pattern, develop it,
>> then tin plate the board, remove the resist, then use ammonium
>> persulfate or something that leaves tin alone and eats copper.
>>
>> So depends on what you wanted.
>>
>> > 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.
>>
>> Take an IC on the board and generate from it a measurement, or use the
>> board edges as a scale. Then scale it up to the desired size from
>> that.
>>
>> > Anything else to consider?
>>
>> It looks as if the paper when scanned was not completely flat, so that
>> can be a small problem. If you could find a back issue of the
>> magazine and then scan from that, it would be a lot better.
>>
>> Harvey
>>
>> >
>> > Thanks guys!!
>> >
>> >
>>
>>
>>
>>
>>

Re: [Homebrew_PCBs] Got some single side boards

2016-04-01 by Harvey White

On Thu, 31 Mar 2016 21:54:50 -0700, you wrote:

>Sorry, what I meant by print the image in reverse is I assume I need to
>'mirror it'. Unless I'm misunderstanding the process, if I printed it as is
>on my glossy paper and ironed it to the PCB copper, I'd end up with an image
>that was backwards.
>

As was said, most PC boards are designed today looking from the top
through the board.

With the photoetch process, you just turned the board over to make the
text come out right, and typical designs were done on the bottom of
the board. The process *does* reverse the image, since from the
board's perspective you're flipping the image by turning it over.
Photoetch, no. Toner transfer, yes.

In eagle, the bottom layer is printed (and is designed mirrored, you
design the bottom layer through the board). So mirroring the bottom
layer is not needed, it's already done that way. Top? no, it must be
mirrored then printed, then it will come out correctly.

That's one good reason to always put text on a board, you can
immediately tell if it's going to be oriented correctly. In toner
transfer, *all* text (when you look at the printed transfer) should be
reversed.

Harvey


>
>
>From: Homebrew_PCBs@yahoogroups.com [mailto:Homebrew_PCBs@yahoogroups.com]
>Sent: Thursday, March 31, 2016 10:54 AM
>To: Homebrew_PCBs@yahoogroups.com
>Subject: Re: [Homebrew_PCBs] Got some single side boards
>
>
>
>
>
>On 31 Mar 2016 10:28:53 -0700, you 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
>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
>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:
>>
>> Is it dark enough to be usable?
>
>I wouldn't be happy with it, no.
>
>> 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.
>
>Change the color palette to monochrome, and then use a very fine brush
>to cover the holes, that's one way.
>
>> I'm assuming using the toner transfer method I need to print the image in
>reverse?
>
>No, the dark area is the toner which is transferred directly. These
>are fine.
>
>>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.
>
>Nope, not at all.
>
>Taken down to a photo/graphics shot and converted into a negative on
>kodalith film, then printed on KPR sensitized boards.
>
>OR
>
>Same process and use a positive acting system, where you coat the
>board completely with resist, print the positive pattern, develop it,
>then tin plate the board, remove the resist, then use ammonium
>persulfate or something that leaves tin alone and eats copper.
>
>So depends on what you wanted.
>
>> 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.
>
>Take an IC on the board and generate from it a measurement, or use the
>board edges as a scale. Then scale it up to the desired size from
>that.
>
>> Anything else to consider?
>
>It looks as if the paper when scanned was not completely flat, so that
>can be a small problem. If you could find a back issue of the
>magazine and then scan from that, it would be a lot better.
>
>Harvey
>
>>
>> Thanks guys!!
>>
>>
>
>

Re: Got some single side boards

2016-04-01 by alienrelics@...

Zoomed in, that looks pretty horrible. Lots of light and dark noise in the scan, wobbly edges because of it.

I'd export it into a format that you can import into your favorite PCB creating software, put it as a background image, and redraw it.

If you want it to look exactly as it does on the original boards (or as close as possible), then I'd bring it into CorelDraw or Illustrator as a background image and redraw it manually.

You can drag it and rotate it to get it lined up and sized correctly, and correct for any image warping.

I just exported it in PDFCreator (free) as a TIFF. PNG will also work, but don't use JPG because it just adds noise.

Here is an Electronic Survivor Shot PCB. I had one to repair that had water damage, so I just duplicated the PCB, moved over the IC, coil, and photodiodes, and replaced the other parts with new. In my case, I cut this on a vinyl cutter so there was no fill. It didn't take terribly long to do this.


Steve Greenfield AE7HD