Topic: What type of paper is this?

[dtkell]

... one could easily remove all of the "tooth" from the surface leaving a shiny plastic that virtually nothing could stick to.

Then you are forced to use some spray matte fixative in order to draw on the shiny surface.
I can smell the stuff just thinking about it!
(I have to watch it before I pass-out!)

[Dinosaur]

There was actually one pencil I found that would write on mylar that had been "detoothed".  A Stabilo pencil of the red variety would do an acceptable patch job on nearly any abused surface.  If you had one that had really been polished, the black Stabilo would work on anything even glass.  The reds could hold a respectable chisel point but the black ones needed a new point after only a few words or lines.

[daron]

Ah, I see I took the first answer too quickly. Sorry to doubt you Chuck. As for what you guys seem to be calling diazo, which I'm not doubting, I have that in two varieties: Blue LINE and Blue PRINT. I never knew there was a difference. The first time I saw the Blue PRINT, I thought it looked like someone was doing there drafting with a scratchboard knife. Why would anyone put that much lead or ink on the paper, I wondered? Then I found mylars that printed as negative for this purpose. I still wonder why anyone would do this. Anyway, thanks everyone for the input. I'm learning more about manual drafting than I ever will need. As well, I'm learning more about the history of the buildings at this school I'm working at. I've only been there a week and with some of the pictures I've seen, some things give me the chills and a haunting feeling. This is the school website if anyone cares.

[Dinosaur]

That blue print you have may have been created with an older oil emulsion process.  The blue line prints are made with the newer ammonia sensitive paper.  I have seen the oil emulsion printers in one or two shops gathering dust but the last time I saw one working was 1970 in my senior drafting class.  We just retired our ammonia based machine this summer.  The reversed sheets you observed were made that way to use the finished print as a base background for a new drawing sort of like Michael suggested.  It was like an xref or locking the background layers to put new work like for an electrical or mechanical plan or the structural steel set.  It allowed changes for the associated design work without damaging the backgrounds.  The pin bars that were mentioned took this a step further and had a methodology very similar to today's layering system for CAD work.  These drawings commonly had 3 or more sheets stacked together and had to be printed with a vacuum frame to assure all of the sheet were printed correctly.

[daron]

Oil emulsion? Maybe that accounts for the weird oily stench on some of the plans I have to go through, huh?

[Dinosaur]

Could be . . . you may find another relic in those plans as well.  Find a sheet with a large section of notes; if these look like they were typed but there is no evidence of an applied "stickyback" they may have been typed directly onto the drawing.  I worked in one shop that had acquired an old Veritype machine that was essentially a huge manual typewriter with a carriage large enough to load a full size drawing.  A weird thing to behold, but it sure beat the snot out of lettering notes by hand or with a Leroy set.

[daron]

WOW! That would be an amazing piece of technology to see. Must have looked like an elephant sitting on a chair. Must have been hard to load the paper and set correctly.

[LE]

Could be . . . you may find another relic in those plans as well.  Find a sheet with a large section of notes; if these look like they were typed but there is no evidence of an applied "stickyback" they may have been typed directly onto the drawing.  I worked in one shop that had acquired an old Veritype machine that was essentially a huge manual typewriter with a carriage large enough to load a full size drawing.  A weird thing to behold, but it sure beat the snot out of lettering notes by hand or with a Leroy set.

no words..... Man, and I started doing technical drafting in 1972... so, that is dated to ? 1889?

for me, mylar was named by the brand name "albanene, herculene.... etc..." but you guys are older than me....

[M-dub]

Some of Dinosaur's early work? 

[LE]

Some of Dinosaur's early work? 

maybe, he did the chisel designs first.... too....

[M-dub]

Yeah, anything in theSwamp where he's referring to a "Tablet", it ain't no digitizer! 

[Dinosaur]

okey dokey FINE ! . . .
laugh it up on the old geezer, but he comes through with a PICTURE of the beast to offer as proof he is not as senile as his user name might suggest.

[deegeecees]

okey dokey FINE ! . . .
laugh it up on the old geezer, but he comes through with a PICTURE of the beast to offer as proof he is not as senile as his user name might suggest.

Oooooo, snaAAP!

[Dinosaur]

Oooooo, snaAAP!

Sorry, I didn't intend to be "snippish" . . . it has been a long  . . . life . . . at least the last two weeks of it anyway.  I was just happy to finally find a picture of the fool thing to convince myself it was a real memory.

[Dent Cermak]

Diazo is really a generic name for copy media that was processed in an ammonia machine. You could do blue prints or sepia prints. Some of the better copy media was indeed on a mylar base. And, y'all, pin graphics rocked!! We did our drawings in the negative engraving method preparing an overlay for each item in the drawing. Then we could make color prints using a color proof system or a contact composite positive using photoscreens to screen the images. looked good to turn out a mylar copy with the contours screened. Made it easier to read.