Blanket Cylinder packing: hard vs soft?

[GazKL440]

So what are your preferences and why?

We have been running soft packing for quite some time now, with the (perceived) benefit of giving the blanket a little more resistance to minor smashes. In this regard they seem beneficial: they'll take a hit and survive (until you put on a high-end job!) and swapping a blanket + under-blanket is a little less dicking around than hard packing sheets...

However....

We are getting a fair amount of dot gain, and given that plates/chemicals/stock etc have not really changed and mechanically both presses are reasonably sound and well within spec setting wise could our under blankets be adversely affecting our print?

Seat of the pants guess tells me (I don't have the equipment to give an accurate figure) we are seeing ~10% gain and we are having to compromise jobs a touch when printing: particularly skin tones in magenta heavy areas.... Do you keep the red panel "red" and make a face look sunburnt or back off your magenta and go slightly "orange" in the red panel?? Honestly it's time consuming and a judgement call I don't like having to make: especially at 3am with no one else there...

I've got some hard packing sheets on order and hope to run a back to back test (at least on the magenta unit), but I'd like some thoughts/opinions on the matter regardless....

Thanks in advance

 

[Cornishpastythighs]

Just some clarification, What are your 'soft' packings made of? Probably the hardest packing is a Permapack Plastic mylar packing which have given good results.

 

[Kaoticor]

I liked the soft packing for some of the reasons you mentioned, we found they also were able to take a few more hits. However, we decided not to use soft packings at our shop due to quality requirements. We got "patchy" spots on heavier ink areas and that is a no-go for us since we have to meet very high quality requirements. Changing out to a hard packing showed immediate improvements for us, so we discontinued soft here.

On your point about adversely affecting print, I thought it definitely did on our shop, but for us it was more of that "patchy" look than a dot gain shift.
I do feel like overall we print a more consistent product with hard packings, but that is only my opinion, not a fact!

-K

 

[GazKL440]

Just some clarification, What are your 'soft' packings made of? Probably the hardest packing is a Permapack Plastic mylar packing which have given good results.

Currently we run a single Bottcher 1.0mm under blanket, I've got some of the under packing board to trial on it tonight if I'm able...

 

[Disappointed]

We run semi-hard manilla under packing, this gives us the best dot generation and despite the very odd smash caused by a folded corner, i can usually go 6-9 months on a set. We could use a 1mm rubber u/b but the dot gain is pretty rough.

I must add that we run waterless so the manilla is fine for these periods.

 

[GazKL440]

We run semi-hard manilla under packing, this gives us the best dot generation and despite the very odd smash caused by a folded corner, i can usually go 6-9 months on a set. We could use a 1mm rubber u/b but the dot gain is pretty rough.

I must add that we run waterless so the manilla is fine for these periods.

Yep that's what I've got now.... The last lot of under blankets we got from Bottcher were the red/orange type with a very slick surface, as opposed to the flat grey ones we previously ran. Four times they slipped out of the clamps, even after I put in new screws and used a file to rough up the surface for better clamping. Not impressed.

I switched 2 units last night to packing board, and both myself and the other printer working agreed that there's a definite improvement in print and dot sharpness, even though the job we are running doesn't really show it too much.

Will replace the rest and report back when I put on a job that'll show any improvement a little more obviously.

 

[jbeniston]

My preference is for softer Packing under the blanket.
I think it helps to lessen shock marks by absorbing the shock caused by the cylinders coming together and separating during the printing cycle. Not forgetting that horrible, 1860's designed, contraption called an ink ductor.
I tried a very expensive plastic packing sheet that had a soft sort of sponge like core. It came from Switzerland. I used only one sheet per blanket and it lasted for six months before it had to be changed. It could be wiped clean too. I cannot for the life of me remember what it was called or where we got it. It was NOT permapak and it was not self adhesive ( although that was available as an option). I found it excellent.
Is your 10%gain purely mechanical or is it a combination of optical and mechanical gain. I find that trying for minimal dot gain is frustrating and counter productive in the end. I try to get all units within 4% and let the prepress handle the rest.
If your estimated 10% gain is mechanical then you have a problem either with prepress or your press. Most machines I find average 1-2% mechanical gain with the rest being optical.
The secret is really to get all the units the same or you run the risk of getting Hue shifts in favour of the unit with the highest gain.

 

[Cornishpastythighs]

Finito self-levelling blanket packing system

Here's a nice product

http://www.folex.com/htm/302/en/Homepage.htm

Here's a Swiss product

 

[Kaoticor]

Finito self-levelling blanket packing system

Here's a nice product

[

Cornish, have you used this product? It looks interesting... If so, do you like it?

 

[Cornishpastythighs]

No have not tried any of those packings.

 

[GazKL440]

Forgot to report back on the results of swapping to hard packing!!

Have ran a few jobs now with the harder packing under the blankets, and must say I'm reasonably happy with the results. I'm getting a sharper dot and visibly less dot gain (visual check only) which means matching a proof has become a much easier proposition, with much less compromise required to get the best result possible.

As I stated in the opening post, a lot of time was being wasted in the make ready process balancing acceptable skin tones against any red solids in a circumferential line... There was never really a happy medium to be found, as one or the other (or both) would not be spot on: and any printer knows that this sort of compromise is...... Irritating.

Now I can get both the solids and the half tones on the money with a minimum of fuss and a lot less stress!! It's a huge relief, not to mention the saving in time and waste.

The only loser here is the local bottle shop lol... Less beer required!!!

 

[Lukew]

I've only ever used the calibrated paper packing, guess this is considered hard packing.
I notice you say with the soft packing you had dot gain which made matching the proof difficult. like any change on the press, be it the type of ink / fountain solution / Blanket / packing etc, if your company requires the print to match a calibrated proof then the press needs to be re-fingerprinted with the dot gain curves adjusted if necessary.
As a printer you probably already know this but unfortunately trying to get management to allow it to be done can be as much fun as hitting your head against a brick wall.

 

[GazKL440]

I've only ever used the calibrated paper packing, guess this is considered hard packing.
I notice you say with the soft packing you had dot gain which made matching the proof difficult. like any change on the press, be it the type of ink / fountain solution / Blanket / packing etc, if your company requires the print to match a calibrated proof then the press needs to be re-fingerprinted with the dot gain curves adjusted if necessary.
As a printer you probably already know this but unfortunately trying to get management to allow it to be done can be as much fun as hitting your head against a brick wall.

Hit the nail on the head Luke. Working with pre press at my factory is an exercise in frustration.... Apparently imposition and plate making is the limit of our pre press, anything else results in "PDF, can't change it, your problem". Maybe I shouldn't have (less than diplomatically!) reminded him that "a few clicks and drags for you means hours of work for me!".... I'll have to work on the inter-factory harmony a little perhaps!

I did chat with the tech that looks after our CTP and processor, he assures me he can modify the curves in the plate maker (what foul wizardry is THIS??) and perhaps help us out. I'll inform him of the results we've achieved with packing, we will run some tests with his equipment and make a decision from there.

I'm pretty happy with the results so far, make ready time is much improved and the worry over compromising part A or part B of a job has lessened!