Whether the platen press is driven by a motor or a foot powered treadle, be safe. Your hands should always be clear of the platen as soon as it begins to close. Gordon-style presses, like the Chandler and Price, have a “dwell”–a brief pause–when open, which allows sufficient time to place a sheet of paper on the platen. Older, cheaper platen jobbers (colloquially known as snappers) open and close continuously and are therefore more dangerous. If the sheet of paper slips or fails to seat in the guides, do not reach in to make a quick adjustment. It is only a piece of paper and not nearly as valuable as your hand. Never go after a piece of mis-laid paper as the press begins to close!

Inking the Press

With a motor-driven platen press, you can ink up the press while locking up the chase. Always begin with very little ink because it is easier to add more than it is to have to take off ink before you even begin the press run. Put a little ink on the ink knife and smooth it down the left side of the ink disk. Running the ink down the left side of the disk helps it distribute more evenly if your form is already in the press. Then let the press run, inking up the rollers as you continue with your lock up. With a treadle press, you can ink up before or after you have completed the lock up.

Locking up the Chase

The furniture in the chase should serve the same purpose as the composing stick does for type: holding it on both sides and at top and bottom. With a platen press, it is especially important to make sure that each line of type is uniformly snug so that no type or spaces fall out or work up. Your form should be complete and ready to lock up when you place it in the chase. In other words, if you have different elements or blocks of type, or combinations of type and cuts, the entire form should be laid out, measured and tied up at the bank. Then it should be moved or transferred to the imposing stone as one unit. When it is necessary to move type (from the composing stick to a galley, from the galley to the imposing stone or bed of the press), always slide it from one place to another rather than picking it up.

Regardless of the shape of the form, the lock up must be done with regard to the shape of the paper; the long side of paper coincides with the long side of the chase. The form should remain tied up until the last possible moment to avoid any accidents. If you want to be able to read the printed sheet as it comes off the press, lock up the form upside down. Whenever possible lock up the type near the center of the chase.

Because the gauge pins will go on the tympan paper of the press on the left and bottom of the platen, the quoins should go on the right and top of the form so that you are locking into your guides. With Hemple (wedge shaped) quoins make sure that the half nearest the type points towards the solid side of the form since the quoin moves. With high-speed quoins, this isn’t an issue. If the type has been set in reference to the length of furniture, in pica increments of fives and tens, it makes a lock up faster and easier.

At the top and right of the form, place a reglet or narrow piece of furniture in between the form and the quoin. Check to be sure the quoins are completely loose when you begin the lock up. Keeping in mind the placement of the paper, center the form in the chase as much as the paper will allow. On a press sheet where the type will only be on one half or the other, this may not be possible.

Working out from the form, put the same length of furniture as the form, then proceed to add progressively longer pieces of furniture until they touch the chase on top and bottom and each side. The corner areas of the chase probably do not have any furniture, so that the locked up form is secured with furniture in a kind of cross shape, i.e. “+.” Once the furniture is all in place, untie the form. There is probably some wiggle room which can be filled in at top and right with leads, slugs, or reglets.

When it’s not possible to add any more furniture or reglet to the lock up, tighten the quoins just enough that they don’t slip or slide. Then use a small planer (which gives more “feel” than a large planer)–a wooden block covered on one side with felt or leather–and gently tap each area of the form. Be sure to wipe the face of the planer with your hand to ensure that it is clean before placing it on the type. Using the handle of the quoin key, rap on the planer, then lift it and move it to the next area. Pick up the planer to move it around rather than sliding it to avoid scratching the type or image. The point of planing down your type and/or image is to make sure everything is on the same plane and level. To this end, make sure the lockup surface is clean and completely free of debris before beginning the lock up process.

Alternate between planing down and tightening each quoin, at the top and right side, until the chase is locked up. Gradually tighten the quoin, using only your thumb and one finger, not the whole hand or fist, to turn the quoin key. Turn the quoin key about 10 or 15 minutes as on a clock face as you alternate with planing. This prevents the whole form from buckling. The form is sufficiently tight in the chase when you can no longer tighten the quoins without exerting too much pressure.

At this point, don’t just pick up the chase to put it in the press. First you must check to make sure the form is locked up securely—this is known as checking to see if the form “lifts.” Place the quoin key under one corner of the chase to raise it off of the imposing stone; using your fingers, gently but firmly press on every line, every image, every quoin and every piece of furniture. You can feel movement if something is loose. If nothing moves, proceed to pick up the chase. If any type or spacing material moves, you must unlock the quoins, add a brass or copper to the loose line or lines and perform the lock up again. Be careful not to add too much material to the loose line or it will cause the lines on either side to become loose.

After everything is completely secure, brush the form lightly, front and back, to remove any dirt or particulates and then stand up the chase and brush the back of the form as well. Before laying the form down again, wipe the imposing stone clean with a rag.

Now you are ready to put the chase in the press.

Positioning the Chase in the Press

The orientation of the quoins in the chase should remain at the top and the right sides. Standing in front of the press, lift the chase so that it is against the bed and rests on the lower ledge. Steady the top of the chase with your left hand. With your right hand at the top of the bed, lift up the spring lever that secures the top of the chase. Be careful not to wrap your fingers completely around the spring lever as it is quite strong and can catch your fingers before it secures the chase. Some smaller presses have a lever that is pressed down with your thumb to lift the catch. In either case, when the lever is raised, push the top of the chase against the bed, release the lever and the chase is secure.

Taking a Proof

Always begin with very little packing under the tympan paper to avoid damaging or smashing anything from too much impression. The tympan paper should be clear of all guide pins, tape, etc. Tympan paper can be used multiple times as long as the new areas to be printed are smooth. Tape a piece of acetate or mylar to the top of the tympan, even as high as the top bale, if necessary. For larger presses it isn’t necessary to have a full sized sheet of acetate or mylar, just one large enough to clear the printed area and accommodate the adjustment of the margins of the paper to be printed.

Whether a motor driven or treadle driven press, proofs are taken by turning the flywheel by hand. It saves wear and tear on the motor by having to turn it on and off repeatedly while refining the impression and position.

Turn the press over (meaning rotate the flywheel away from you and by hand so that the platen closes and opens again, coming to rest with the rollers at the lowest possible position) so that an impression is made on the acetate or mylar. This may require several tries until there is adequate packing under the tympan for the impression to show. This is much better than beginning with too much packing and smashing your type and/or image because of too much pressure. Once there is an image on the acetate/mylar, the paper to be printed is placed under it and moved until it is in the desired position. It is helpful to draw vertical and horizontal lines for straight orientation, or lines drawn where the first and last lines should be, or whatever other pre-drawn aids might help in positioning the paper under the printed proof. Once the paper is in position, tape it on the right hand side. The tape shouldn’t be very tacky, just enough to hold the paper but so that it will pull off easily without damaging the tympan sheet. Rub the tape on your shirt to pick up some lint and that usually removes enough of its tackiness. With the paper taped in position, the acetate/mylar can be removed. Wipe the proof impression off with a dry rag and it is ready to use again.

Setting the Guide Pins

There will be two guide pins on the bottom of the platen and one on the left side. The most common guide pins are Kort or Gardner Adjustable Quad Guides. These have little teeth to grip the tympan paper, two brass arms on either side which open and close the “mouth” and a tongue to hold the printed sheet down. The part that opens widest is the part put in the tympan paper, to allow room for adjustment. Make a slit in the tympan paper about a quarter of an inch away from the edge of the paper to be printed. Having enough room to adjust guide pins allows the paper to be straightened as necessary.

Once the guide pins are in position, turn over the press slowly by hand, standing to the side to check to make sure the guide pins clear the form and will not smash anything. This can happen when printing with an aluminum or magnetic base and the paper will be close to an edge of the base, or if the paper is small and printing near the edge of the form. Also, be sure the brass tongue of the guide is not sticking out too far so that it interferes with anything. If you want any type and/or image to bleed off the edge of the paper, the correct way to do this is to print on a larger sheet than the finished size and then cut the paper down to size when all printing is complete.

If everything is clear, then roll the press over (still by hand) and print on the paper. While still in the early stages of proofing, any paper of the same weight can be cut to press sheet size and used for makeready press sheets if the actual press sheets are valuable or in short supply.

Adjusting Impression

It would be nothing short of a miracle if the first proofs were perfect impressions. There are usually uneven areas of printing at first. The lighter areas need to be built up. We are not taking into account the inking yet, just the impression of the type or image on the paper. While the correct amount of impression is debatable and will vary from project to project, a good starting point is just enough impression that it is visible when the sheet is held to a raking light, but not so much that it is prominent on the back of the sheet.

The impression is built up carefully and gradually with varying thicknesses of paper, acetate, mylar, card stock, etc. Once the overall impression is as good as can be but certain areas are not yet printing evenly, thin bits of smaller paper can be used under, or over, those areas. To be accurate, print on the tympan paper and then place the thin pieces directly under, or over, the areas which need building up. Tearing the paper used for make ready, rather than cutting it gives it feathered edges which do not cause drastic differences in the impression. These thin pieces can be secured with thin paste or glue sticks applied thinly. If the make-ready is under the tympan paper, the ink then needs to be cleaned off the tympan paper with type wash. Sometimes, there is only one letter or one line causing trouble. You can cut a thin piece of tape the size of the letter(s) or line(s) and place it directly over the printed area on the tympan paper. The rest of the ink on the tympan needs to be cleaned away with type wash, but be careful not to remove the tape as you do it.

The makeready might require several layers to finally achieve an even overall impression. If the makeready, whether paper and/or tape, is on top of the tympan paper, a sheet of acetate/mylar can be placed over the whole area so that the paper can be fed to the guides without catching on anything. In that case, a piece of packing must be removed from under the tympan paper so there is not too much impression.

Adjusting Ink

There should be very little ink on the ink plate and rollers when beginning makeready. Once an even impression is achieved, the inking is evened out. Sometimes, as the printing progresses the ink lays on unevenly and unpredictably. A number of things that can cause this are addressed in floor model platen troubleshooting.

It is always safest and best to leave the chase out of the press while it is being inked up. That avoids over-inking the form. However, small amounts of ink can be dabbed on the ink disk while the press is in motion and after the chase is in the press, if the ink is put on just past where the rollers pass over the form, at around 6:30 or 7:00 on a clock face. Adding small amounts of ink in this way allows the ink to be distributed evenly by the rollers before it passes over the form again. A small Speedball brayer is very handy for adding ink to the ink disk. Just roll out some ink in a thick layer on a piece of marble tile and add regularly to the disk as described above.

Placement of Grippers

Grippers are not always necessary but can be very useful when the paper is slipping or sticking to the rollers, as can happen with text-weight stock or a large form. To begin the set-up on the press, the grippers should be removed from the press or moved all the way to the farthest sides of the press. If they become necessary, they can still remain entirely outside the printed area, even entirely outside the printed sheet. All that is required is a rubber band or string between the two gripper bars, taking care that they do not interfere with the type/image being printed. More than one band may be used between the grippers. Special metal fingers were sold that clip onto the grippers. Gripper fingers reach in from the side to help pull off the printed sheet.

Feeding Techniques

Letterpress printing is a right-handed world. The guides on the press will be at the bottom and on the left. That means it is the right hand that feeds the paper into the press and the left hand that takes it out of the press. The faster the left hand removes the paper, the more time the right hand has to place the paper. The paper should be swept into the guides in a diagonal motion that pushes the paper into the corner of the bottom guide and the left guide.

Practice getting a rhythm to feeding the paper before you pull the impression lever. If the press has a variable speed, begin with it somewhat slower rather than faster.

Have a stack of paper convenient to your right hand. Not all presses have feed tables, but have something about level with the feed table that is attached to the press so that your stack is easily within reach. Begin with a piece of paper in your right hand. Extend both hands, elbows straight, holding them just above where the press closes. If your elbows are bent, then your hands are pulled back and they won’t be in position to place the paper when the platen opens. Holding your hands just above where the press closes, the left hand should be under the right hand. That way, just as soon as the press begins to open, the left hand can reach in quickly and pull the printed sheet out as the right hand is moving the new paper into position almost simultaneously. Fasten a folded strip of coarse sandpaper over the middle finger of the left hand and you will not only pick up the printed sheet more easily, you will be much less likely to smear the wet ink.

If a paper slips or you don’t get a paper in the press in time, do not reach back into the press to correct the mistake. It is only a piece of paper. Instead, simply push the impression lever (also known as the throw-off lever) away quickly (don’t slam it). That way, nothing gets printed on the tympan paper. A platen press thrown off impression will still crush your hand if it is between platen and press bed when the press closes. If the tympan paper does get printed on, stop the press and clean the tympan paper with type wash. Print a couple of scrap sheets to make sure everything is clean on the back of the sheet. Then continue printing.

Of course, feeding the paper into the press one sheet at a time by hand is only as easy as being able to pick up the paper from the stack. It helps to fan the paper a bit so that the edges stick out for easy picking. Stretch a large rubber band or two across the feed table to keep the pile of paper from vibrating off and falling. Wearing latex rubber surgical gloves can be helpful because they help grab the paper more easily. There are also rubber fingers which can do the same, but sometimes these fall off. A flat can (printers liked Copenhagen tins) with a folded bit of cotton rag and saturated with Glycerin can be placed near the feed board. A touch of Glycerin on the fingers helps keep them tacky.

Stacking Printed Sheets

As you take the paper off the press with your left hand, it is usually okay just to stack the paper one on top of the other and keep the press going. This works if there is not a lot of ink on the press because of a large printed area, or if you are not printing on paper that will set off easily from the front of one sheet to the back of the one on top of it (coated paper often has this issue). If you are stacking the paper, take great care in jogging up the printed stack so that you do not rub or smudge any printed areas. Do not put any pressure on the stack until you are sure the ink is dry. This means you must often wait at least until the next day to cut or trim any freshly printed sheets to avoid offsetting the ink.

Slip-sheeting is a method of inserting a thin, unprinted sheet of stock between printed pieces in order to avoid set-off. If you are printing by yourself and the paper needs to be slip-sheeted, print one sheet, push the impression lever away, slip-sheet the printed paper, pull the impression lever, print, and so on. Run the press at a comfortable speed (if you have a variable speed motor) or let more than one turn of the flywheel go by as you slip-sheet with the impression lever off.

Old record racks which can sometimes be found in thrift stores are good for holding printed sheets. You can get 20-50 sheets per rack depending on how many 45s or LPs it once held.

Removing the Chase

To remove the chase, use your left hand to brace the top of the chase and then, with your right hand, release the lever holding the chase. Allow the chase to lean forward as you release the lever. With a hand on either side of the chase, lift it up and clear of the press.

Clearing the Tympan

Once the chase is removed, remove all guide pins from the tympan paper. Remove any make ready and packing from on top of or underneath the tympan sheet. This avoids any unpleasant surprises and accidents the next time you put a newly locked up form in the press.

Cleaning the Press

Printers use many different things to clean the ink off a press which includes the ink plate and the rollers, not to mention the ink knives and, possibly, brayers.

For a non-toxic, low VOC alternative, you can go to your kitchen cabinet and get a bottle of vegetable oil or Crisco. There will be some oily residue which will yet have to be cleaned up with a solvent. A commonly used, effective solvent is California Wash. It pretty much does the job on the metal parts and will not harm rubber or composition rollers. Crisco may be preferable to vegetable oil, as it won’t drip down into the press. Eco House, a low-VOC printmaking solvent from Canada, or even rubbing alcohol, may be used to remove the residue from the rollers.

If you are going to quickly switch to another color and there is a residue of solvent on the press, Rubber Rejuvenator can be used to remove any final residue of ink and solvent. It evaporates quickly but not as fast as type wash. A non-scientist’s rule-of-thumb is that the more quickly something evaporates, the more toxic it is. An organic vapors mask is a good thing to have in the studio as well as protective gloves. The filter on the mask may have to be replaced from time to time (when you can smell the solvents, it is time to change the filter). When the gloves get holes in them, change the gloves.

Type wash can clean things other than type like polymer plates, photoengravings, linoleum blocks, wood engravings, etc. Do not use type wash to clean the press. It evaporates so quickly that it will not clean large areas efficiently. It may also cause rubber rollers to shrink and harden.

Wipe the ink plate first by placing a rag spread open over the entire surface of the ink plate. Then saturate the rag with the solvent of your choice. Wipe the ink plate clean, including the edges. Then fold the rag carefully into a neat bundle and, standing by the side of the press and with the rollers at their lowest possible position, wipe all surfaces of the rollers that you can reach. When you have done that, rotate the flywheel so that the rollers come up a bit and wipe all areas on all the rollers that you can reach. Keep doing that and by the time the rollers reach the ink plate, they should be pretty clean. Wipe all surfaces with a clean, dry rag in the same order taking not to leave lint on the rollers.

You may also apply a few sheets of scrap paper or newsprint onto the disk and roll the rollers carefully over the sheets to remove as much excess ink as possible before starting in with the rags.

After cleaning the press, remember to leave the rollers in the lowest possible position, or remove them entirely to relax the saddle arm springs and make sure they are thoroughly clean.

Resources

Ralph W. and Edwin Polk, The Practice of Printing, Seventh Edition, Peoria, Illinois, 1971.
C.W. Hague, Printing and Allied Graphic Arts, Milwaukee, 1957.