Homebrew_PCBs

I'm using laser transparencies for photoresist boards and I would like to
test a real photographic film image. I understand real film has solid black
this is excellent at blocking light. Can anyone suggest a type of place
that can do photonegatives from a .jpg or .bmp? Can a CVS or Riteaid do
this?

Jeff

On Tue, 12 Apr 2016 17:13:31 -0400, you wrote:

>I'm using laser transparencies for photoresist boards and I would like to
>test a real photographic film image. I understand real film has solid black
>this is excellent at blocking light. Can anyone suggest a type of place
>that can do photonegatives from a .jpg or .bmp? Can a CVS or Riteaid do
>this?

You want a professional place, one that does drawings, engineering
prints, and the like. They're likely to have the ability to make the
image. Photolithographers, for instance. Riteaid or CVS barely know
how to develop Tri-x Pan.

Harvey

>
>Jeff

On Tue, 12 Apr 2016 18:20:56 -0700, you wrote:

>I did a bit of this in my college days. We used orthographic film
>(Kodalith, I think) that was not sensitive to reds and had very high
>contrast.

It was kodalith. It may no longer be available. You had a two part
developer that was used to give you that almost step contrast. If you
developed it in Dektol it would give you a gray scale.

>It was fairly easy to use for me and give great results. I made
>contact prints from mylars taped with Bishop tapes and pad layouts. I used
>it under a ruby light with a carbon filament. (Something my Dad had in his
>basement photo area, along with an old enlarger and developing trays.) Ahh!
>The good old days.

You forgot the 8x10 view camera....

This gave you a negative, and you had to use that with something like
Kodak KPR... nasty stuff.

Harvey

>
>
>
>Andy
>
>
>
>From: Homebrew_PCBs@yahoogroups.com [mailto:Homebrew_PCBs@yahoogroups.com]
>Sent: Tuesday, April 12, 2016 4:23 PM
>To: Homebrew_PCBs@yahoogroups.com
>Subject: RE: [Homebrew_PCBs] images for photoresist
>
>
>
>
>
>That is simple to develop.i haven't done it in a while but it was d76
>developer , stop bath and fixer . you have to work in total dark until the
>fixer. If the size is 8 by 10 you could put it in a photo processing drum
>and let a motor do it for you. You would just need to drain the chemicals at
>the proper time.
>
>A friend of mine used to do it with lithograph film . I don't think it was
>as touchy and it could be handled under a yellow light if I recall.
>
>
>
>From: Homebrew_PCBs@yahoogroups.com [mailto:Homebrew! _PCBs@yahoogroups.com]
>
>Sent: Tuesday, April 12, 2016 5:24 PM
>To: Homebrew_PCBs@yahoogroups.com
>Subject: Re: [Homebrew_PCBs] images for photoresist
>
>
>
>
>
>On Tue, 12 Apr 2016 17:13:31 -0400, you wrote:
>
>>I'm using laser transparencies for photoresist boards and I would like to
>>test a real photographic film image. I understand real film has solid black
>>this is excellent at blocking light. Can anyone suggest a type of place
>>that can do photonegatives from a .jpg or .bmp? Can a CVS or Riteaid do
>>this?
>
>You want a professional place, one that does drawings, engineering
>prints, and the like. They're likely to have the ability to make the
>image. Photolithographers, for instance. Riteaid or CVS barely know
>how t! o develop Tri-x Pan.
>
>Harvey
>
>>
>>Jeff
>
>

On Tue, 12 Apr 2016 19:22:39 -0400, you wrote:

>That is simple to develop.i haven't done it in a while but it was d76
>developer , stop bath and fixer . you have to work in total dark until the
>fixer. If the size is 8 by 10 you could put it in a photo processing drum
>and let a motor do it for you. You would just need to drain the chemicals at
>the proper time.
>
>A friend of mine used to do it with lithograph film . I don't think it was
>as touchy and it could be handled under a yellow light if I recall.

Kodak Kodalith, 2 part developer, stop and fixer. Red light is fine.

gave almost a complete black and complete transparent, wonderful
stuff. However, there were two types, the line and the dot. Dot was
used for newspaper photographs, and line is what you wanted.

Harvey

>
>
>
>From: Homebrew_PCBs@yahoogroups.com [mailto:Homebrew_PCBs@yahoogroups.com]
>Sent: Tuesday, April 12, 2016 5:24 PM
>To: Homebrew_PCBs@yahoogroups.com
>Subject: Re: [Homebrew_PCBs] images for photoresist
>
>
>
>
>
>On Tue, 12 Apr 2016 17:13:31 -0400, you wrote:
>
>>I'm using laser transparencies for photoresist boards and I would like to
>>test a real photographic film image. I understand real film has solid black
>>this is excellent at blocking light. Can anyone suggest a type of place
>>that can do photonegatives from a .jpg or .bmp? Can a CVS or Riteaid do
>>this?
>
>You want a professional place, one that does drawings, engineering
>prints, and the like. They're likely to have the ability to make the
>image. Photolithographers, for instance. Riteaid or CVS barely know
>how to develop Tri-x Pan.
>
>Harvey
>
>>
>>Jeff
>
>

Way back in my hand taping days before CAD layout tools, we would lay a board out using Mylar film, ruby tape and Bishop dip and doughnut  pads. This was done at 2:1 then sent to an industrial photo house to be reduced 2:1 on lito-film. IIRC it  was about $20 to $50 for a set of negatives and more if you wanted a set of contact positives.   I saved some cost at home by doing my own contact positives.  Making the contact prints was fairly easy -- just a couple pieces of glass to clamp the films together, a darkroom safe light, some slow litho-film, developer and fixer.  Took around 20 minutes to do the entire process.   The positives were used with boards spin coated with Shipley AZ111 positive resist, exposed then etched.  Turn around for the photo house was 24 hours but you could pay for 1 hour service if you were in a rush.  Eventually all the photo houses switched over to laser plotters once PCB CAD systems became available.  Even the photo plotting houses went by the way side once the PCB fabricators started to accept digital Gerber input files.

You can still buy litho-film, the developer and fixer from places like Freestyle Photographic Supplies. Though the web site seems to be down.  The ideal thing would be to build your own photo plotter

Criag

On 13 Apr 2016 12:58:28 -0700, you wrote:

>Way back in my hand taping days before CAD layout tools, we would lay a board out using Mylar film, ruby tape and Bishop dip and doughnut pads. This was done at 2:1 then sent to an industrial photo house to be reduced 2:1 on lito-film. IIRC it was about $20 to $50 for a set of negatives and more if you wanted a set of contact positives.

There were two ways of doing this. One was to use black donuts and
black crepe paper tape. This would work well with one sided boards.

The other method was to use the black crepe for the pads, and then red
transparent and blue transparent tape for the other layers. Red tape
could be shot with Kodalith, because it was sensitive to blue only and
red was no light (hence opaque). Blue tape was shot with panchromatic
film with a red filter (making the blue drop out). Panchromatic film
was sensitive to all colors.

>I saved some cost at home by doing my own contact positives. Making the contact prints was fairly easy -- just a couple pieces of glass to clamp the films together, a darkroom safe light, some slow litho-film, developer and fixer. Took around 20 minutes to do the entire process. The positives were used with boards spin coated with Shipley AZ111 positive resist, exposed then etched. Turn around for the photo house was 24 hours but you could pay for 1 hour service if you were in a rush. Eventually all the photo houses switched over to laser plotters once PCB CAD systems became available. Even the photo plotting houses went by the way side
>once the PCB fabricators started to accept digital Gerber input files.

And it took a bit to get there. Good computers and all sorts of
stuff.

>
>You can still buy litho-film, the developer and fixer from places like Freestyle Photographic Supplies. Though the web site seems to be down. The ideal thing would be to build your own photo plotter

Or do toner transfer, or send out to China for the boards, etc....

Main problem is the sensitized board, which can be a bit dear.

Harvey

>
>Criag