What is a "pressed" poster?

[Dread_Pirate_Mel]

It's obviously a process of flattening folded posters but how does it work and how much does it cost?  This "pressed" BFT looks great:

[Harry Caul]

Here is how Bruce described it in another thread:

I read a cool scientific study once where scientists admit they have no clue why paper can be rolled for a minute, and lose all "memory" of it, but leave it rolled for a few hours and it starts to "remember" the roll. Just as odd, leave it flat under weight for a few days and it keeps it "memory", but leave it for a couple of months, and it loses its "memory" again!

I did not see it done, but here is almost surely how the Lawrence was "pressed". You put it in a drymount machine, but put paper and/or towels on each side, and set it to a very low heat for a very short time, and the folds greatly "relax" and practically disappear.

If you think it is strange that a $10K LOA was subjected to this, know that it was also done to the $97,000 King Kong one-sheet I auctioned at Christie's, which was the closest thing to a mint poster I could ever imagine!

Bruce

[Harry Caul]

By the way, I would be interested in hearing about how much this costs and who provides this service as well...

[crowzilla]

The process of gel-backing posters that some restorers are using now will also nearly flatten out all the fold-lines of a poster.
I see it being used more and more on inserts and half-sheets instead of paper-backing, and less frequently on one-sheets.

The dry-mount form of pressing initially became popular in comic-book circles nearly a decade ago and is slowly being used more and more by poster restorers.  The easiest and most frequent use of course is to press folded corners and lines on lobby cards.

[Harry Caul]

I'm reviving this thread in the hopes that someone has some more specific experience with this process.  I know someone at the local frame store who has access to a dry mount machine that can handle paper up to 42x60.  If we can get the process working, theoretically the only thing we couldn't press in one shot would be a french 1p.  For big posters like Italian 2p and 3-sheets, one could press each piece and then (acid free) tape them together.  The ultimate goal here would be to flatten and frame posters like 1-sheets, Italian 1ps, 3-sheets, etc... where the paper is still strong, but without the need for linen/paper backing.

So how exactly does this work?  There are four key aspects to using a dry mount press: time, temperature, moisture and pressure.

1) How should I prep the poster (if at all)?  Would you recommend using a deacidification spray first?

2) What temp should the machine be set to?  I think they can usually go as high as like 350 degrees F.

3) How long should the poster be pressed to flatten the poster without damaging it or making it brittle?

4) Should the poster be completely dry when it is pressed?  Or should I dampen it (or leave it damp from the deacidification spray if used)?

5) What pressure should be used?  I think most machines go up to like 13 psi.

6) What should I line the machine with (if anything)?  Bruce said paper or towels (!) above... if so, what kind of paper?  Acid free?  Buffered? 

If anyone can help I'll be sure to post the results of my experimentation here so others can have this done at their local framers.  This might be a good solution to avoid linen backing for cosmetic purposes... Thanks in advance!

[Dr Hackenbush]

I know when it comes to comics it's trial and error with regards to how much pressure and moisture.  That's why people that get into pressing comics practice on cheaper ones to fine tune the process.  If I remember correctly, they line the top and bottom of the press with an acid-free type of mylar, otherwise the pattern of the press will transfer to the comic.  I've seen the result of not lining it 

[jayn_j]

My parents were portrait photographers, and I learned dry mounting at a young age.  It was primarily used to mount photos to backing board, but we also used it to quickly flatten material that had curled as well.  We would also dry mount damaged photos for restoration.

Memory says that we ran the press at 250-275 degrees.  That seems right because you could touch the press, but didn't want to leave a finger there more than an instant.  We used cardboard to protect the photos.  If you placed them directly against the press, you stood the chance that the emulsion would peel off and stick to the press.  I imagine that acid free board would make more sense, but never foam board.  I don't have a good feel for timing.  For mounting, it was around 15-20 seconds.  For decurling, we would use a lower heat setting and keep it there several minutes.  The main advice is to experiment on junk posters.  I also figure that the rules are going to be different for the vintage pulp stock and the more recent glossy stock.

Please take all of this with a grain of salt as we were mostly concerned with proper display and nobody was thinking toward conservation.

[Harry Caul]

I know when it comes to comics it's trial and error with regards to how much pressure and moisture.  That's why people that get into pressing comics practice on cheaper ones to fine tune the process.  If I remember correctly, they line the top and bottom of the press with an acid-free type of mylar, otherwise the pattern of the press will transfer to the comic.  I've seen the result of not lining it 

Thanks Doc, I'll definitely experiment lining with mylar.  It also sounds like I need to extra careful that the folds are properly flattened before pressing so misfolds don't get pressed in permanently!

[Harry Caul]

My parents were portrait photographers, and I learned dry mounting at a young age.  It was primarily used to mount photos to backing board, but we also used it to quickly flatten material that had curled as well.  We would also dry mount damaged photos for restoration.

Memory says that we ran the press at 250-275 degrees.  That seems right because you could touch the press, but didn't want to leave a finger there more than an instant.  We used cardboard to protect the photos.  If you placed them directly against the press, you stood the chance that the emulsion would peel off and stick to the press.  I imagine that acid free board would make more sense, but never foam board.  I don't have a good feel for timing.  For mounting, it was around 15-20 seconds.  For decurling, we would use a lower heat setting and keep it there several minutes.  The main advice is to experiment on junk posters.  I also figure that the rules are going to be different for the vintage pulp stock and the more recent glossy stock.

Please take all of this with a grain of salt as we were mostly concerned with proper display and nobody was thinking toward conservation.

I appreciate all the thoughts Jay.  It definitely sounds like I'll need to experiment.  I'll be sure to control for paper type as well... I hadn't thought of that.   

Anyone else have experience pressing posters that can share their thoughts?

[Dread_Pirate_Mel]

John Davis at Poster Mountain was telling me about this process.  It is labor intensive so it's more expensive than linen-backing.  It's been a week or so but I believe he said you put the poster between heated water pads.  I'll ask him to send a more detailed description.