Weird spots in print

Hi all,

We are after a bit of help if anyone is familiar with our problem!
We are printing some postcards with some ink-heavy areas. We’re aware of the general salty look of letterpress and love it to bits but we are having problems with other, larger speckles coming up in the prints.

FYI, we are running a 1960 Heidelberg Windmill.

In most cases the specks are turning up in different parts of each print - we haven’t come across 2 exactly the same. It is not even across the whole print, rather localised to one section on each print, so it looks more like a mistake than a general letterpress quirk. Please see the images below for a better indication of what I’m talking about.

We have tried washing the rollers down twice thinking it could be a dust problem. I guess it still could be particles floating about in the air and settling onto the rollers but we are still a little unsure.

We’ve also rotated the rollers and have tried rotating the plate.

Our rollers are only a year or so old and don’t appear to have any wear on them as yet.

We can use less ink and run them all through twice to get a less speckled look but time is not on our side and there are quite a few to do. We’ve found it’s also harder to monitor the colour this way and it is important the prints stay close to their pantone match.

Has anyone had a similar issue and know of a way to fix the issue?

Claire & Mitch

image: photo9.JPG


image: photo10.JPG


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Just to add - we use rubber based Vanson inks

Looks like trash from the paper shavings getting in your ink.

Clean your press so lint pieces aren’t everywhere and back trim your paper to get a clean, debris free edge.

See if that helps.

Also, it’s not usually roller related. The windmill is blowing dust directly onto the plate.

What kind of paper are you using? I can’t imagine that paper dust would give such a broad problem in your ink coverage. For dust on the plate to create a problem like this it would have to suddenly blow on after the rollers pass over the plate, before the plate hits the paper. You would also be seeing a build-up of crud in your ink. I suspect the paper you are using is the problem, just not in the way described above.


Hi casmit & Paul,

Thanks for your answers. The paper is back trimmed by a local printshop and is always supplied beautifully cut so I’m not sure if that is the issue, though I will fan out the paper and make sure there is no debris.

The paper we are using is 600gsm (220lb) Lettra so it is quite toothy & porous. We use this paper alot and have only seen this issue twice, the first time wasn’t a great drama because the detail was so fine and the specks weren’t this noticeable.

had a problem few years ago with offset ltho-the ink rollers plucking paper fibre from the paper surface(Frabriano Rosapina, nice colour but very liittle size…….could be for you?…….so I just added tack reducer. Just a thought.

I’ve always been disappointed with Lettra. I know it is all in fashion to use it these days, but I find it to be a non-supple, almost brittle paper that doesn’t take ink well, especially on solids. Dampening might help it, but it is difficult to run it that way on a sheet-fed press. I prefer the Arches line for heavy, dry papers. Arches 88 prints beautifully, even if you are printing with a spoon (which I have done). Rives is a good brand, but does better dampened, as do most of the European mould-made papers. If you figure out that you are actually pulling fibers out of the paper I recommend a product called I.C.Compound Ink Corrective, it looks like a paste wax but blends with your ink without changing color and reduces the tack very nicely. I’ve been using it for 30+ years. They make a good hand cleaner too.


As I recall from my student days, the term is picking. The adhesive ink picks fiber from the paper. It messes up the paper and the ink.
The solution is to either reduce the tack sufficiently, or switch to a harder surface paper.

litho NVTI Certificate-Press Common Printing Faults: Sheets failing to separate and feed,
mis-register, non-drying of ink film,
set-off, picking and plucking, tail
end book, slur, paper stretch, fluffy,
roller repeat and ghosting, bleeding,
catch-up, scumming.
Practicals and
Demonstration with trainee

Hi all,

Thankyou for your comments. We’ve been tearing our hair out over this job! We only have limited windows of printing time in and around our day jobs but we have spent the whole weekend trying new methods. Our latest tests are the worst yet. The fibres look like worms and are all over the print. Not pretty! But we can actually tell they are fibres now so at least we know what we’re working with.

We are going to test another type of paper - maybe the gmund cotton as it is fairly accessible (next day delivery) and we’ll just have to ask the client nicely for an extension.

Paul, we’d like to try the arches but this job requires 600gsm stock (it’s double sided and client wants moderate amount of impression). Will give it a go for other jobs though! Thanks for your recommendation of an ink corrective - we will definitely order some and see how it goes.

For now we have used ‘230 ink conditioner’ by Hurst. It has reduced the tack heavily but has not reduced the specks or ‘picking’ in any way. Thanks inky for that term :)

Appreciate all your help!!

Fingers crossed we can sort this issue out before I have no hair left!!

i wonder if you hit the sheet with no rollers if it would compress the fibers then ink the form and hit it again?? never tried this before but what you got to loose. Usually reducing the tack does the trick.


Your mention of worms provides a clue I supect. You might try to blow your paper clean before you print.

Also wipe the rollers clean (with your hands or fiber free cloth) before applying ink.

Sounds like your fiber worms are being added to the mix through neglect. Once they attach to photopolymer they literally have to be rubbed off. Use a fast drying solvent for cleaning the form and fiber free cloths in wiping the form. Blow dry.



what do you use as a fast drying solvent? Been looking for a decent type wash.


When plate washes disappeared from the scene I started looking around for what the old fellows used. In Printing with the Handpress Lewis Allen recommended white gas. Today’s equivalent is Coleman’s Lantern Fuel. I’ve been promoting it ever since. Works great. It’s so commonplace it is dirt cheap compared to the discontinued plate washes. I can even get it at the local grocery store in the camping area.


Anybody know where to find the fuel? There’s one seller on Amazon selling it at what seems like a huge markup. Other retailers that do have the listing say “store only”.

If not online, where? I’ve seen the lanterns at Target but not the fuel. Nothing at Home Depot. Grocery stores in the NYC area don’t have camping areas unfortunately! We have EMS and REI stores now, maybe there…

The trade name is Naptha, and it can be purchased at hardware stores. White gas is a misnomer that leads people to actually buy gasoline which is full of carcinogens and dangerously flammable. Gasoline can ignite spontaneously. Naptha is flammable as well, and the fumes tend to accumulate near the floor, which can build-up and ignite if there is a spark, so use only in a ventilated area.


If you run out of everything to clean your type, try your wifes Nail varnish remover she might not appreciate it when she needs it but it works a treat, its in the shed dear.


Nail polish remover is usually Acetone which will also remove the paint from your press. I have found no real use for Acetone in a print shop, although touching it with your finger and instantly tasting it is a real trip.



Nail polish remover (acetone variants) might work on metal type but will destroy photopolymer plates with the mere touch.


And many nail polish formulas include oil which will leave a residue on metal type.


Naptha here in Australia is called ‘Shellite’ and can usually get it at any hardware store or camping store. Its what I use in my pump-up primus camp stove but also works as a super fast drying solvent. But as mentioned above, make sure there is plenty of ventilation.


I’m with inky on this one. My student days would also indicate picking or plucking. Inks a bit stiff so reduce the tack a little. I use Van Son inks on linocuts and have had this show up. Generally though the paper I use is very forgiving. (Rosapina)

Occasionally, you will see an effect like this when the ink is absorbed unevenly , those areas where the ink has not been absorbed show as little light blotches among the dark colour . A common problem when printing on ivory boards, usually cured with an underpin of lighter shade or change the material to something that dries back evenly
Running fibrous stock will as mentioned above have problems if not backtrimmed , if additive to the inks does not change matters then i would consider the different material route .


I’m sure you’ve solved the problem a while back now but, since I can’t tell from your pics I was wondering if you could use a bit more impression? Something that might solve a problem like this is Setswell Compound, an ink additive that increases the flow of ink across the printing surface without having to reducing the tack. It’s extremely useful for solids that do not contain small details.


re cleaning type

Where I worked, hot metal stopped on November 22, 1975.

We used a cleaner called X55 to remove ink from metal type; the name is probably a Shell company product identifier. Also used for cleaning Lino matrices and keyboard cams, etc. Highly flammable; a friend using a somewhat similar product burned down his house. On one occasion we were supplied with X40, which seemed more volatile. It was rumoured that, in another town, someone used X55 as automotive fuel, illegally, during wartime petrol rationing.

It is claimed that a compositor in Melbourne, Australia, noticed the cooling effect of the solvent then used, thought about it, probably conferred with friends, and mechanical refrigeration was developed; this led to Australia’s trade sending frozen meat to Europe. It is claimed that, earlier, ice was imported from North America to Australia to be sold in premises selling alcohol for consumption (we call them pubs, abbreviation of public house). When a rich drinker left his ice after consuming the alcohol, other men fought for possession of the ice.

Naptha, Coleman’s Spirit, White Spirit were all known (and I remember seeing them used) in Australia. One different kind of heating stove used kerosene, but needed pre-heating; some lino pots ran on kero for fuel, and I heard an apprentice burned down the premises because of a failure to correctly light the petroleum-fuelled (gasoline) lino pots.

The fumes of most cleaners are dangerous. One of my friends has just been in hospital to have a tumour removed from the bladder, possiblly originating in some of the dangerous chemicals used, but we cannot be certain.


We get the coleman kerosene at walmart, comes in a little blue jug..its only like two bucks……

Coleman fuel (white gas) and kerosene are two entirely different things, and very few stoves are designed to burn both.

I think they use this as more of a lantern oil than a stove fuel.
We use it for cleaning up the jackets and such…Looks like this…

image: DSC04683.JPG


i never saw coleman keroscene before, i thought they only had the gallon containers of coleman fuel (white gas).

I prefer not to have more flammables on hand than I have safety containers. Kerosene is the only one I buy by the gallon, the rest I purchase by the quart at my local hardware store. I use:

Kerosene as a general cleaning solvent. It evaporates slowly so it is not great for a wash-up while your job is on the press. But it does evaporate over night.

Naptha is a good general type wash; quick evaporating and strong enough for most cleaning. If I am running a job and need to wash the rollers I will use Kerosene for a general wash-up followed by a quick cleaning of the rollers with Naptha, so I’ll be ready to run without a lot of paper loss. Most commercial roller/press washes are about 75% Naptha with other oils and solvents added to slow down evaporation. Naptha = White Gas = Coleman Fuel

Odorless Mineral Spirits I have a bit of a problem with because the lack of odor makes you think you aren’t breathing in bad fumes, but you are. I still use it when other people are present who might be offended by the odor of Kerosene. I don’t find it any more effective than Kerosene, but it does evaporate slightly faster.

Denatured Alcohol is great for cleaning tympans after a miss-feed, it evaporates very quickly so it doesn’t buckle the tympans. It also is great for cleaning old, dirty wood furniture, I don’t know why it works so well for that one job, but it does. Because it evaporates so quickly it is very flammable, so caution should be used around spark producing machinery.

Lacquer Thinner is the strongest and most flammable of all the solvents I use. I find it very good for cleaning very dirty type, but it is very nasty to breathe so I use it very sparingly, and move the rags outdoors after use until they dry. It will remove paint. Even a drop of it will soften paint and finishes, so try not to use it around presses or cabinets. I have used it on wood type, and it will remove the shellac coating very quickly, making the surface absorb ink (necessitating a re-coating of the type). I use it to remove the paint from old type cases prior to repainting more than anything else.

After 30+ years of being involved with letterpress printing I have not had much need for any other solvent. I must add that if I had a high-speed press I would spring for an appropriate wash-up solution; something that didn’t evaporate too quickly with a good ink cutting quality. Keep your solvents in appropriate safety containers, and if you keep more than a gallon of anything most fire departments demand that you have a fire-proof cabinet.

Do not use commercial gasoline as a cleaning solvent. It is loaded with carcinogens and is incredibly flammable.



Ha. A picture certainly is worth a thousand words! I’ve seen this for sale. Is it odorless by chance? Of all the solvents I’ve used, kerosene is the only one whose smell I cannot tolerate. Plus it takes so long to dry and leaves an oily film it seems useless as a rubber roller wash. Is this different?


Gerald-emailed you some info..

Wierd. Revise that to: “Coleman Stove Fuel” is white gas, kerosene is lantern fuel. I’ve never seen a solvent used on type or press that was blue, except for one litho plate cleaner. You don’t want to wash presses with a solvent that has been colored—unless you are just printing black next. Get some other kerosene for rollers where slow-drying characteristics degrade rubber less, get white gas for type and plates where you don’t want any residue.
I don’t mind the smell of regular kerosene, but deodorized kerosene bothers me. I think that’s because it is deodorized for combustion, not for use as a room-temperature vapor.

The Kerosene is not blue, although you can buy some lamp fuels that are colored. Kerosene is sold and stored industry wide in blue containers. Gasoline (not white gas which is Naptha) is sold and stored in red containers.


Hi there. Mitch here, Claire’s partner with Ruby’s Tuesday. Thanks everybody for the help throughout this.

We’ve had the same wormy trouble on a second job using paper from the same order batch, and at this point we think we’ve narrowed it down to one of two things - the paper (as suggested quite a few times - the more we use lettra 600, the more we are looking at alternatives) and the rollers.

New rollers are on their way this week, and our four current ones are going to be reconditioned, so it’ll be interesting to see if there is any difference there.

We have a feeling that the stock has been guillotined down from mill sheets in too tall stacks, which would explain the edges of the sheets, they aren’t in great condition - there is an unusual amount of ‘dandruff’ and other tidbits flying about when they go through our windmill from the ragged edges. We tried an alternative supplier and it might just have to be chalked up to a lesson learnt, move on and don’t make the same mistake twice.