Packing and impression

I was hoping someone could explain to me the influence of the hardness/softness of packing on the depth and sharpness of my impression.

I’m using photopolymer plate and having a blind emboss to do on a wedding invite soon.

I know I can control the impression with the impression lever on my Heidi but I understand from posts here that packing can have an effect?

Also, is there a protocol about which way around you print things, do I do the emboss before the inked plates or doesn’t it matter what comes first.

Thank you.

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I would print first, then emboss. I prefer a hard pack. I like to use enamel paper for packing because it is hard and holds up well under pressure. If you want a deep impression on the printing, you could put a piece of dental dam or an old offset blanket under your tympan paper. This is what I call soft packing, although I am sure others will pipe up soon with their methods.

Thank you Girl with a kluge, that’s helpful. I just did an impression test with the 360gms paper stock I’m planning to use for the invites, basically gently increasing the impression on the impression lever until I was happy.

Now the depth of the impression is nice and there is only very slight show through on the reverse. It could be a little sharper though…could the softness of the packing influence sharpness or is that just down to my paper stock?

Look at the printing under a loupe. Is the image bleeding? Print on a different paper and then you will know if it is the paper or something else.

My tests were without ink, just embossing so no bleeding.

The impressed bit just doesn’t look quite as sharply embossed as I have seen done online.

cannot help on embossing, in all my years of printing only been asked once about embossing a job and said I would not know where to start, but it did get me thinking if it would be possible to make a male and female die using polymer plates, negative film for one and positive film for the other, you could manipulate your image on a computer to give an outline or space around your type or image, I use magnetic bases and the polymer would have to be steel backed put one on the base and then the other one on top polymer to polymer, apply double sided tape to the top take a pull and hopefully this will stick to the tympan and release from the magnetic base. Perhaps this would work better on a hand platen or treadle but if you just had 1 sheet of tympan paper the and the polymer the grippers might clear it, this is all theory on my part I have never tried it but would love to know if this would be possible, also if like me you might dabble in engraving using pantograph engraving machines, you could in theory use positive film to make any type or image on a polymer plate and use that as your template for engraving, the possibilities could be endless but this is all untried as yet, any thoughts, John.

John you could certainly make a negative and positive polymer plate, I have no idea if that is something people do to get a better emboss.

For the wedding invite I have next week I had been hoping just to push the plate into the paper with a good impression on but my tests with the paper stock this week are fairly deep but not that sharp, thus this thread. I think if it’s sharp you don’t actually need so much depth of impression for it to look nice.

Maybe I haven’t chosen a soft enough paper stock.

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Of course photopolymer can be usd for matched male/female embossing dies, but for the female die you need a positive spread, not the same negative as used for the main plate.
No need for that if just doing a simple blind deboss. Use a suitable thick compressible stock and you don’t even need to think about soft packing. Soft packing will take the fibers and stretch them on the back of the sheet, where a hard packing will give sharper definition as the sheet is compressed.

Most brass embossing dies are designed to have a counter die made by molding a material into the die shape. There are materials made which can be mixed up and applied to a board mounted on the platen, covered with a thin plastic sheet, and then the press is closed on it to force the material into the die. When the press is opened after a brief dwell, the counter die is in exact register with the die itself, and contains all the detail of the die.

I have had some success with making photopolymer dies of the KM-73 plate material sold by Boxcar Press. It only has a .020” relief, which is ample for most embossing done without heat. I use a hot-melt stick in a heated gun to make the counter-die on the press, and can get excellent results when embossing some paper stocks. It takes a bit of experimentation, and you don’t want to pick a hotmelt stick which stays sticky (some of the 3M ones do). This will only work for fairly small images as the hotmelt will harden prior to closing the press if you need to cover too broad an area. I have had some success in doing such an image in stages, however.

After the press is opened again, simply trim off any of the counter-die material which has squeezed out at the edges of the die. I generally mount a sheet of cardboard or pressboard on the platen with double-stick tape on which to build the counter-die.

I have also use auto body putty (Bondo) to produce the counter-die, but it takes a longer dwell with the press closed to firm up. Make certain you use a barrier sheet of thin plastic material between the Bondo (or other material) and the die, so it will strip off the surface and not permanently bond the platen to the die!

If you use standard thickness photopolymer material, you most likely will not be able to “bottom out” the impression, and thus will not get a very sharp edged emboss.

Also make certain that you wedge the chase into a fixed position by inserting leads, reglets or wads of paper between the press and the edge of the chase so that it doesn’t shift during the run. If it shifts by a very small amount, you will crush either the die or the counter-die, and the embossing will suffer.

John Henry

there is a thick board that is layered that can be used to make the embossing counter, you close the press and it sticks to the platen then you have to cut away the board around the embossing , its a lot of work and time consuming but will work for a simple die. can’t remember what they call it or even where i got it, i think Astor Universal.