Making smaller pictures

I know nothing about darkroom equipment. I am interested in reducing
picture sizes. Specifically I make my own circuit boards, but I am
wanting switch over to photographic methods to be able work at smaller
sizes. The plan it to print an image to a transparency and then produce
a smaller image.

It looks like I would use a photographic enlarger, but I can not find
any information about how that would be used for image reduction.

Can someone point me in the right direction as far as literature or
equipment.

wrote

I know nothing about darkroom equipment. I am
interested in reducing picture sizes.


I think a camera is usually used. Is'nt a reduced
size image of your copy that is needed? Dan

On Fri, 21 Jan 2005 02:24:10 GMT, PGG
wrote:

Of course I've _never_ used it before as why
would I ever want to make a reduction of a 4x5 negative??

You wanted a wallet-sized photo ?


Regards,

John S. Douglas, Photographer - http://www.puresilver.org
Please remove the "_" when replying via email

On 20 Jan 2005 18:16:05 -0800, wrote:

I know nothing about darkroom equipment. I am interested in reducing
picture sizes. Specifically I make my own circuit boards, but I am
wanting switch over to photographic methods to be able work at smaller
sizes.

Rather than use photography, you might consider generating your PC art
with a laser printer. I have been able to produce art for .010 inch
lines with .010 inch spaces on translucent mylar. The mylar art is
contact printed on photo-sensitized PC board in the same way a
photographic negative would be . You need a PC layout program that
will produce the output format reqired for a laser printer. I use a
program called "Easy-PC for Windows" by Number One Systems.

Chris Ellinger
Ann Arbor, MI USA

I already use the toner transfer technique and have gotten great
results from it. Down .4mm pin spacings, even though that one was a
challenge. However I am looking to achieve better quality and also be
able to get down to smaller scales.

wrote

I know nothing about darkroom equipment. I am interested in reducing
picture sizes. Specifically I make my own circuit boards

It looks like I would use a photographic enlarger,
No. You need a reducer! Er, camera.

but I can not find any information about how that would be
used for image reduction.
Natch.

Can someone point me in the right direction as far as literature or
equipment.

What you are looking for is a 'process camera'. These are available
on ebay and from local printing shops for not very much money, a
few hundred dollars max. Some print shops will give one to you
for free if you will haul it away, but some cameras are 12 feet
long and weight is measured in tons: so look out!.

A small 14x18" camera capable of 3x reduction is what to look for.
nuArc VV1418's are quite common and very easy to use: two people,
or one with a hand cart, can move it. With a bit of disassembly it
will fit into a small station wagon, they are about 4.5 feet tall.
Agfa Repromasters are usually 20x24" and take up a bit more room,
but are also common. A process camera can make copies of both
reflective artwork (IJ/LJ printer) and transmissive artwork
(remember paper-crepe tape on mylar? - they can make a copy
of a piece of film is the useful feature).

A problem with photographic methods is that most do-it-yourself
PC boards have 'positive resist': as for exposing with printer-output
artwork. With a camera you will get a negative film that you will have
to contact print to another film to get a positive film.

If you are patient, and the material is _very_ sensitive, you can
expose the PCB directly in a process camera if the a/w is illuminated
with quartz-halogen lamps. This is a _lot_ less work for 1-of boards.
A process camera has a vacuum back and will just suck the PCB board to the
platen for exposing.

All that said...

If your board size is less than 4x5" then an enlarger can be used
as a copy camera: you put the film where the negative should go,
the artwork where the paper should go and illuminate the artwork
for 10-15 seconds with some bright lights. The lith film and
developer are easily available, and the film is not red sensitive
so you can see what you are doing with at bright red safelight.

_Do not_ try to use an ordinary camera for PCB work (unless you are OK with
really sloppy dimensions). Camera lenses have too much distortion.
Getting the camera _exactly parallel_ to the artwork is a PITA, though
it can be done with the ole' two mirror trick.

Enlargers and process cameras are made (or should be made) for precise
alignment.

--
Nicholas O. Lindan, Cleveland, Ohio
Consulting Engineer: Electronics; Informatics; Photonics.
Remove spaces etc. to reply: n o lindan at net com dot com
psst.. want to buy an f-stop timer? nolindan.com/da/fstop/

Thanks for the execellent explanation and information. I did see a
nuArc on ebay for $50 starting bid. Too bad it is in Massachusetts and
weighs 300lbs. However, the boards I make at most get to 4x5 so the
photographic enlarger would should work for a start.

For the photographic enlarger, do you think an lcd display could be
used in place of a copy of the image. Not sure if a backlit display
would be bright enough, but maybe an older reflective display. I
suppose contrast could be a problem as well.

I do not think that the issue of positive and negative would be a
problem. I could just print the image out opposite to the correct
display.

I also ordered a few books on darkroom techniques. Hopefully that will
increase my understanding of what all will be required to attempt this.



Nicholas O. Lindan wrote:
wrote

I know nothing about darkroom equipment. I am interested in
reducing
picture sizes. Specifically I make my own circuit boards

It looks like I would use a photographic enlarger,
No. You need a reducer! Er, camera.

but I can not find any information about how that would be
used for image reduction.
Natch.

Can someone point me in the right direction as far as literature or
equipment.

What you are looking for is a 'process camera'. These are available
on ebay and from local printing shops for not very much money, a
few hundred dollars max. Some print shops will give one to you
for free if you will haul it away, but some cameras are 12 feet
long and weight is measured in tons: so look out!.

A small 14x18" camera capable of 3x reduction is what to look for.
nuArc VV1418's are quite common and very easy to use: two people,
or one with a hand cart, can move it. With a bit of disassembly it
will fit into a small station wagon, they are about 4.5 feet tall.
Agfa Repromasters are usually 20x24" and take up a bit more room,
but are also common. A process camera can make copies of both
reflective artwork (IJ/LJ printer) and transmissive artwork
(remember paper-crepe tape on mylar? - they can make a copy
of a piece of film is the useful feature).

A problem with photographic methods is that most do-it-yourself
PC boards have 'positive resist': as for exposing with printer-output
artwork. With a camera you will get a negative film that you will
have
to contact print to another film to get a positive film.

If you are patient, and the material is _very_ sensitive, you can
expose the PCB directly in a process camera if the a/w is illuminated
with quartz-halogen lamps. This is a _lot_ less work for 1-of
boards.
A process camera has a vacuum back and will just suck the PCB board
to the
platen for exposing.

All that said...

If your board size is less than 4x5" then an enlarger can be used
as a copy camera: you put the film where the negative should go,
the artwork where the paper should go and illuminate the artwork
for 10-15 seconds with some bright lights. The lith film and
developer are easily available, and the film is not red sensitive
so you can see what you are doing with at bright red safelight.

_Do not_ try to use an ordinary camera for PCB work (unless you are
OK with
really sloppy dimensions). Camera lenses have too much distortion.
Getting the camera _exactly parallel_ to the artwork is a PITA,
though
it can be done with the ole' two mirror trick.

Enlargers and process cameras are made (or should be made) for
precise
alignment.

--
Nicholas O. Lindan, Cleveland, Ohio
Consulting Engineer: Electronics; Informatics; Photonics.
Remove spaces etc. to reply: n o lindan at net com dot com
psst.. want to buy an f-stop timer? nolindan.com/da/fstop/

wrote

For the photographic enlarger, do you think an lcd display could be
used in place of a copy of the image.

That's getting pretty low-rez, isn't it?

Not sure if a backlit display would be bright enough
but maybe an older reflective display. I
suppose contrast could be a problem as well.

I would not bother. And lith film is slower than treacle.

I do not think that the issue of positive and negative would be a
problem. I could just print the image out opposite to the correct
display.

I tried that. I failed. I use a LaserJet for output and the printer
just doesn't like make a uniform black over large areas. My Calcomp
1043 would just grind forever and run out of ink. And my software
won't work properly with the ink-jet I have.

I also ordered a few books on darkroom techniques. Hopefully that will
increase my understanding of what all will be required to attempt this.

It should. You may want to check your library for books on 'Pre-Press Graphic
Arts' and 'Lithography'.

I am sure Usenet/WWW has a group or two on home-brew PC boards where
you may get more (and better) advice.

It doesn't cost that much to have a service buruae take your Gerber
files and mail you back the films the next day. Probably less than
setting up a darkroom and enlarger or process camera. But it just
wouldn't be as much fun.

--
Nicholas O. Lindan, Cleveland, Ohio
Consulting Engineer: Electronics; Informatics; Photonics.
Remove spaces etc. to reply: n o lindan at net com dot com
psst.. want to buy an f-stop timer? nolindan.com/da/fstop/

Nicholas O. Lindan wrote:
javaguy11111

I am sure Usenet/WWW has a group or two on home-brew PC boards where
you may get more (and better) advice.

My question started out in the homebrew pcb group at
http://groups.yahoo.com/group/Homebrew_PCBs/

No one really had much information about the technique. A lot of people
have done printing to transparency and exposing, but no reduction
techniques.

Homebrew_PCBs is a very active and informative list. I am sure many
people in that group would be interested in hearing you describe the
technique in more detail. Pictures are good too.

I did find out there is a local art museum that offeres classes in
darkroom techniques. So I will sign up for that class when it is
offered in a few months. That should give me the best opportunity to
find out if this method is the way I really want to go.


It doesn't cost that much to have a service buruae take your Gerber
files and mail you back the films the next day. Probably less than
setting up a darkroom and enlarger or process camera. But it just
wouldn't be as much fun.

Agreed


--
Nicholas O. Lindan, Cleveland, Ohio
Consulting Engineer: Electronics; Informatics; Photonics.
Remove spaces etc. to reply: n o lindan at net com dot com
psst.. want to buy an f-stop timer? nolindan.com/da/fstop/

Two things, you need more extension between lens and carrier than you can
usually get on an Omega D-2 or D-3, Omega made extension bellows for both
units (Auxiliary Focus Units or some such name, I have one for each system)
to get more distance between lens and film plane (sort of like macro
photography). With enough extension you can use shorter focal length lenses
that will not normal "cover" a given negative size and that will yield even
more reduction. With a D-5 or Besseler MC-series there is "extra" bellows
length and auxiliary attachments are not normally need. For other enlargers
you can usually rig something to get the extra extension (I used the lid to
a spray paint can as a spacer between lensboard and lensmount on a D-2 one
time and attached the two boards with 2" long screws).

The second issue is focus. It is much easier to rack the lens out to the
approximate reduction needed and then focus by moving the enlarger up and
down the column than to try to focus using the bellows. Trust me, it
doesn't work since your reduction ration changes with changes in lens to
film plane distance. If you can't bring the enlarger head down far enough
to achieve focus raise the easel with paper boxes or books.

--
darkroommike

----------
wrote in message
oups.com...
I know nothing about darkroom equipment. I am interested in reducing
picture sizes. Specifically I make my own circuit boards, but I am
wanting switch over to photographic methods to be able work at smaller
sizes. The plan it to print an image to a transparency and then produce
a smaller image.

It looks like I would use a photographic enlarger, but I can not find
any information about how that would be used for image reduction.

Can someone point me in the right direction as far as literature or
equipment.