Inking Problems with Cranes Lettra


I’m having problems printing decently on Cranes Lettra. I’ve supplied my local printers with mag blocks and some Lettra, and they had had the job running this afternoon on an old Heidelberg. And it looks like this – see attachments. I’d like it looking clear and clean, with a slight impression, and without the squidged ‘outlining’ effect. Are we using the wrong inks? Or too much ink? Or too little pressure? Any ideas?



image: one.jpg


image: two.jpg


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Lettra has problems but it looks to me like you need to adjust the height of the rails — that sort of slur will happen when they’re sitting too low.
I don’t know the precise terms for it but have a look at both sides of the press and you’ll see the rail adjustment, a top and bottom point on both sides with a +/- and the ability to adjust out and in after loosening the hex bolt. You’ll want to adjust it out (towards the + if I remember correctly but it will be obvious). It will take some fine-tuning but you should have a crisp impression once it’s fixed.
A secondary concern may be ink that is too loose but the bleed suggests the rails are to blame.

3 more things:
— could be too much ink even after the rail adjustment
— probably obvious but keep the rail height consistent at the four adjustment points
— clean up the rails, gunk can accumulate

Yeah, it looks like too much ink, rollers are too low, and it also appears that the ink could be too thin. Make sure you are using a good stiff ink. If it runs freely off the knife, its too thin. And like Pearl mentioned, make sure the rails are clean and dry. You can also apply a thin coat of spray powder on the rails to give them some traction. You may also want to slow the press down to about 2600 as well, at least until you get the problem ironed out.
And make sure the cut has no residue left on it from the etching process.
I am curious about the ink though. What are you using?

Hi Everyone,

Thanks for all your thoughts, much appreciated. The ink, I think, may be normal Litho ink – I’m not the printer, but I think it is. Is this the problem?


If in fact the ink is suspect, it is only a part of the problem, The rollers are still too low.
The reason the ink is peaking my interest, is because in your pictures, it appears that there is too much ink, as well as not enough ink on the same impression, like it’s being “squidged” (a printing term I wasn’t familiar with until your post) off the cut.
If the problem contiues after these suggestions, I’ll teach you some 4 letter printing terms that might help. But for sure, Lettra isn’t at fault here.

Hi Bill, Hi Pearl,

Thanks for your advice. Much appreciated. I’ll pass it on to the printers on Monday. I made up the term squidged! When you say the rollers are too low on the rails, what does this mean for the ink? That it’s over inking? Or inking the sides of the relief parts of the block? Is it inking and pushing the ink away from the type face? I will tell the guys to sort the roller height out, and use a nice thick ink. Is there something they can add to the ink to make it thicker? Or is it a case of using proper letterpress inks? Is it better to have a transparent ink or an opaque one?



The rails are adjustable, so when the rollers are too low, the rail adjustments are set too low. In your case, they may be set ridiculously low and as you said, really pushing the ink off the type face and onto the shoulders.

Regarding ink, there are things to add to the ink to make it thicker, but it can be an extreme measure when most inks work fine as is. As far as “proper” letterpress inks, they are few and far between these days. A modern day ink that resembles the letterpress inks of old is Charbonnel. It is marketed as etching ink. Most oil and rubber base inks do work fine, but I have seen them thinned down too far with additives or mixing.
In my opinion, opaque inks are better, as they hold out the desired color better, but the majority of inks on the market these days are transparent, and usually work fine too.
If you have trouble getting your point across to the pressman working on this project, look up my info here, and have him call me. I’d be happy to help.

Hi Bill & Pearl,

Thanks for all your help, much appreciated. All sorted!