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 Im misunderstanding the process, if I printed it as
>> is on my glossy paper and ironed it to the PCB copper, Id 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.
>>
>> > Im 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 Ive 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 its 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 Im 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!!
>> >
>> >
>>
>>
>>
>>
>>