photographing vellums

[John Larkin]

We're only a bit into the 21st century, so I still draw schematics on
D-size vellum, but I'm finally giving up on the old diazo/ammonia
blueline machine to make copies for other people.

These drawings photograph poorly, but I've found a way that works
pretty well: tape them to a window backwards, so they photograph by
transmission rather than by reflection. Transmission is the way that
the blueline machine worked. Low room light helps.

https://www.dropbox.com/s/s84vehtr5uyk2s5/Vellum_Window.JPG?raw=1

Irfanview can flip and tweak the image and make a pretty good pic.

I'm not sure why backwards helps, but it seems to.




--

John Larkin Highland Technology, Inc

lunatic fringe electronics

 

[Jan Panteltje]

On a sunny day (Tue, 02 Jul 2019 08:12:12 -0700) it happened John Larkin
<jjlarkin@highlandtechnology.com> wrote in
<s2smhehnd8q4lneghdhus9skniov3pkf86@4ax.com>:

We're only a bit into the 21st century, so I still draw schematics on
D-size vellum, but I'm finally giving up on the old diazo/ammonia
blueline machine to make copies for other people.

These drawings photograph poorly, but I've found a way that works
pretty well: tape them to a window backwards, so they photograph by
transmission rather than by reflection. Transmission is the way that
the blueline machine worked. Low room light helps.

https://www.dropbox.com/s/s84vehtr5uyk2s5/Vellum_Window.JPG?raw=1

Irfanview can flip and tweak the image and make a pretty good pic.

I'm not sure why backwards helps, but it seems to.

Yes cameras are good for that.
Does it also work when you hang it in front of a monitor that displays white?
I have no 'vellum' here to try, a white rxvt in Linux makes a nice white screen.
Adjustable brightness at that.

I use 'xv' in Linux to modify pictures.

 

[Winfield Hill]

John Larkin wrote...

We're only a bit into the 21st century, so I still draw
schematics on D-size vellum, ...

https://www.dropbox.com/s/s84vehtr5uyk2s5/Vellum_Window.JPG?raw=1

What, is that a drafting table? I moved mine out
of my lab over 25 years ago. Hmm, I didn't see
a drafting machine.


--
Thanks,
- Win

 

[John Larkin]

On 2 Jul 2019 08:44:54 -0700, Winfield Hill <winfieldhill@yahoo.com>
wrote:

John Larkin wrote...

We're only a bit into the 21st century, so I still draw
schematics on D-size vellum, ...

https://www.dropbox.com/s/s84vehtr5uyk2s5/Vellum_Window.JPG?raw=1

What, is that a drafting table? I moved mine out
of my lab over 25 years ago. Hmm, I didn't see
a drafting machine.

Yes, that's in fact a custom-built drafting table. I like to sit or
stand there, look at the birds and plants [1], and draw. I find
drawing with a good pencil a lot faster and more creative than working
on a screen.

I do use some design automation, an electric pencil sharpener and an
electric eraser.

I use blue-grid paper and follow the lines, so I don't need a drafting
machine. Looks fine.


[1] and ambulances. We're a few blocks from the Zuckerberg [2] SF
General Hospital, the major trauma center around here.

[2] He bought it for his wife.



--

John Larkin Highland Technology, Inc

lunatic fringe electronics

 

[John Larkin]

On Tue, 2 Jul 2019 19:14:05 +0200, Arie de Muynck
<no.spam@no.spam.org> wrote:

On 2019-07-02 18:02, John Larkin wrote:
On 2 Jul 2019 08:44:54 -0700, Winfield Hill <winfieldhill@yahoo.com
wrote:

John Larkin wrote...

We're only a bit into the 21st century, so I still draw
schematics on D-size vellum, ...

https://www.dropbox.com/s/s84vehtr5uyk2s5/Vellum_Window.JPG?raw=1

What, is that a drafting table? I moved mine out
of my lab over 25 years ago. Hmm, I didn't see
a drafting machine.

Yes, that's in fact a custom-built drafting table. I like to sit or
stand there, look at the birds and plants [1], and draw. I find
drawing with a good pencil a lot faster and more creative than working
on a screen.

I do use some design automation, an electric pencil sharpener and an
electric eraser.

I use blue-grid paper and follow the lines, so I don't need a drafting
machine. Looks fine.

Maybe an alternative idea: 30 years ago I used to draw on A3 sized
sheets of paper, printed for us with very thin blue lines, 5x5mm grid.
They had a black title block and edge with 1-2-3 and A-B-C markings.
When photocopying the blue lines disappeared. Pencil lines became black,
good enough for first discussions with clients. Also did the 3-D
drawings on those, looked fine.
Of course later they were inked, on real drawing paper laid over the
paper drawing.

Arie

I give my hand-drawn schematics to my PCB layout guy, who enters them
into PADS and then does the board layout. He often has to create new
library parts, which I don't have to do while I'm designing. I leave a
lot of design notes on my vellums, that would clutter up a CAD
schematic.




--

John Larkin Highland Technology, Inc
picosecond timing precision measurement

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com

 

[Arie de Muynck]

On 2019-07-02 18:02, John Larkin wrote:

On 2 Jul 2019 08:44:54 -0700, Winfield Hill <winfieldhill@yahoo.com
wrote:

John Larkin wrote...

We're only a bit into the 21st century, so I still draw
schematics on D-size vellum, ...

https://www.dropbox.com/s/s84vehtr5uyk2s5/Vellum_Window.JPG?raw=1

What, is that a drafting table? I moved mine out
of my lab over 25 years ago. Hmm, I didn't see
a drafting machine.

Yes, that's in fact a custom-built drafting table. I like to sit or
stand there, look at the birds and plants [1], and draw. I find
drawing with a good pencil a lot faster and more creative than working
on a screen.

I do use some design automation, an electric pencil sharpener and an
electric eraser.

I use blue-grid paper and follow the lines, so I don't need a drafting
machine. Looks fine.

Maybe an alternative idea: 30 years ago I used to draw on A3 sized
sheets of paper, printed for us with very thin blue lines, 5x5mm grid.
They had a black title block and edge with 1-2-3 and A-B-C markings.
When photocopying the blue lines disappeared. Pencil lines became black,
good enough for first discussions with clients. Also did the 3-D
drawings on those, looked fine.
Of course later they were inked, on real drawing paper laid over the
paper drawing.

Arie

 

[Bill Sloman]

On Tuesday, July 2, 2019 at 7:27:44 PM UTC+2, John Larkin wrote:

On Tue, 2 Jul 2019 19:14:05 +0200, Arie de Muynck
no.spam@no.spam.org> wrote:

On 2019-07-02 18:02, John Larkin wrote:
On 2 Jul 2019 08:44:54 -0700, Winfield Hill <winfieldhill@yahoo.com
wrote:

John Larkin wrote...

We're only a bit into the 21st century, so I still draw
schematics on D-size vellum, ...

<snipped more antiquated practices>

I give my hand-drawn schematics to my PCB layout guy, who enters them
into PADS and then does the board layout. He often has to create new
library parts, which I don't have to do while I'm designing. I leave a
lot of design notes on my vellums, that would clutter up a CAD
schematic.

That's odd. Computer aided design usually lets you hide design notes so they only clutter up the schematic when you turn them on. The philosophy is that the schematic just presents the information that the viewer needs - it reflects the net-list and displays it in a way that's more or less human-comprehensible - but there can be a whole data-base behind it (including all the printed circuit layout information) which really would clutter up the schematic if your tried to display it all.

--
Bill Sloman, Sydney

 

I use a Brother MFC6490CW all-in-one, and it produces good scans of B-size vellum drawings. $300, no chips in the ink cartridges, no worries.

Cheers

Phil Hobbs

 

[Clifford Heath]

On 3/7/19 1:12 am, John Larkin wrote:

We're only a bit into the 21st century, so I still draw schematics on
D-size vellum, but I'm finally giving up on the old diazo/ammonia
blueline machine to make copies for other people.

These drawings photograph poorly, but I've found a way that works
pretty well: tape them to a window backwards, so they photograph by
transmission rather than by reflection. Transmission is the way that
the blueline machine worked. Low room light helps.

https://www.dropbox.com/s/s84vehtr5uyk2s5/Vellum_Window.JPG?raw=1

Irfanview can flip and tweak the image and make a pretty good pic.

I'm not sure why backwards helps, but it seems to.

It's because pencil produces a lot of top-surface reflection.

I'm always dissatisfied with photos or scans of pencil drawings for that
reason. Even after you apply a radical brightness/contrast adjustment
they're just no-where as good as if done in ink.

Maybe if could be better if you use radical side-lighting, like below 30
degrees of incidence.

Clifford Heath.