Registration on C & P

REGISTERING HINTS for a hand fed platen:
1 Make sure that every sheet is fed accurately into very stable lay pins.
2 Don’t push the sheet excessively against the lay pins and bruise the edge as this will wear the edge for subsequent colours.
3 Pushing the sheet excessively against the pins may cause it to bounce away from the pins.
4 Hopefully, you have quoted on the use of a substantial stock that doesn’t behave too flimsily.
5 If the paper is thin and/or prone to curling along the bottom two lay pins, you might need to remove the inclination to curl by using the brass finger on the pin and so limit the slip and looseness when laying on the lay pins, making the paper lay completely flat against the tympan. If your lay pins are of a primitive/home made variety, strips of slightly upward curling card can be stuck to the tympan to help the sheet lay flat. If the paper lays loose and curls in the lays it will minutely alter the position of the image on the sheet, and if the sheet doesn’t lay consistently the same it will never register.
6 Plan to print the register part of the form close to the 3 lay pins, because any stretch or shrinkage on the paper due to moisture or dryness in the atmosphere will be at its minimum nearest the pins.
7 Try to let your paper cure in the room it will be printed and try to print on a climatically stable day.
8 When placing the forme in the type bed of the machine make sure it is always firmly pressed and located to one consistent side of the bed. You are probably aware of the looseness possible in the type bed for easy removal of the forme. Keep the bed and forme clean of dust and oil for consistency.
9 Use the same chase for the different colours.
10 Cleverly made up formes, and if mechanically safe, can use Notting style quoins to make minor register adjustments within the forme without removing from the press
11 The friskets need to be positioned and adjusted to stabilize the paper during the feeding operation so as not to dislodge the paper from the lay pins and during impression.
12 Slow the machine down to a controllable speed.
13 Multi colour jobs requiring close registration deserve to be printed on quality stable stocks tending towards the non-porous type. Don’t be mis-lead in thinking that a cheap or porous stock will save the client money, because in the end it will cost you, the printer, money and profits instead.
In Australia, we have a saying “horses for courses”.
14 There must be more hints, but they’ve slipped my mind for the moment
William Amer, Australian
Compositor and Machine Minder

William,
Thank you for the good tips…

Could you also mention a few hints about measuring and lining up plates without registration marks? Each magnesium, wood mounted plate (type-high) i have for 2 color are very different/inconsistent in size making for reforming/lining up very challenging… ideas/tips, please?

Dawn, New Mexican (USA)
illustrator/designer
novice letterpress printer

To add a thought to the great and thorough list above is to always put your quoins toward the same sides each time.

Typically when I’m standing at the imposing stone I use the quoins against the bottom (toward me) and the left side. Then when I put the chase into the C & P the coin is at the top (pushing essentially toward the side of the chase that is locked in the most and on the right side pushing the type toward the registration pins.

If I have the room in the chase I always try to use a long piece of metal furniture along all four sides to try and distribute the pressure to the case as wide as possible. That way you don’t risk bowing the center of the chase’s side a lot. Even small amounts of extra pressure can then cause the type to move a small amount.

To Dawn in New Mexico,
thanks for your “thanks”.
A simple method of registering plates on odd size bases is to get a wooden “t” square and attach a sheet of flexible, but stable clear film to one of the arms, it could have fine graph lines printed on it. Find the block in your set which will give you the most points to help register other colours and lock it into place along with the other components of the forme. Pull machine proofs and position this colour till right in the machine.
Take the forme out of the machine, clean it of ink!
Take the t square and attached film and lay it over the forme at the bottom left corner, re-ink the block component only and take a thumb proof on the film. [Remembering that in letterpress we read upside down, left to right and the top images of the forme are closest to your belt/tummy.]
Then in another same size/same machine chase position the second colour under the clear plastic thumb proof and lock it into position. With a little practise the second colour is now ready for makeready and then printing. When the register is made to your satisfaction under the film, unlock the forme and drop in a 2 or 1.5 lead space in your make up, this will move the newly positioned second colour out of register by those two points and your trained eye will be able to see if the newly made space between the key colour/proof and the second block is equal in all points of contact. Don’t forget to remove the 1.5/2pt lead ‘coz the machine makeready person will blow his top and you’ll cop a kick up the backside for costing the proprietor money!!
A good compositor will makeready as much as possible before it gets to the machine because, as like today, the old machine would not be allowed to be idle and unproductive for too long. By having Notting quoins on all sides of the block, the finest adjustments can be made with just the slightest squeeze, but remember to have the forme in that constant place in the machine bed.
If your machine is very busy with another minder/operator, you can use galleys and impose all the colours in preparation for those first key colour proofs.
Of course the ideal is to relay and reregister the plates on new wood, using the same techniques as described above.
Finally, if the formes are made of a single block each colour and large enough, try placing Notting quoins 2 to a side near the block corners, [being 8 quoins]. This will allow you the opportunity to “swing/twist” the position of the block to get register.
Good comping, William Amer, Australian
Compositor and machine minder.