HOW TO PRESS COMIC BOOKS

 Following the order of operations when pressing comic books is critical because each step prepares the book for the next, and performing them out of sequence can permanently lock in defects, weaken paper fibers, or create new damage that cannot be reversed. Inspection prevents wasted effort on books that cannot be safely improved, while documentation establishes a clear condition baseline. Dry cleaning and stain removal must occur before humidity and heat, as pressing first can set dirt and oils deeper into the paper. Humidification makes fibers pliable, which is essential for effective dent removal and successful pressing. Pressing too early, skipping rest periods, or rushing storage and shipping increases the risk of reversion, gloss damage, or warping. In short, the process is cumulative and technical; respecting the order ensures consistent results, protects the book’s structural integrity, and preserves maximum collectible value, as outlined in my 2025 book,  Comic Book CPR: First Edition. 

Pressing isn’t just about machines — it’s also about the space you work in. Paper is highly sensitive to temperature and humidity, which means the environment around your press can directly affect your results. The ideal range for pressing is 70–75°F (21–24°C) with a relative humidity of 40–50%. This range keeps the paper fibers flexible enough to relax during pressing, but not so damp that they swell or wrinkle.

 If your room is too humid, the paper can absorb excess moisture, which often leads to problems like spine waves, rippling, or even mold growth if books are left unchecked. On the other hand, if your environment is too dry, the paper becomes brittle and less responsive to pressing, which increases the risk of tears, split spines, or color rub. 

 Another important concept is reversion — this happens when a book looks great right after pressing but slowly begins to “bounce back” to its previous shape. Reversion is often caused by pressing in unstable conditions where the temperature or humidity fluctuates. A consistent environment ensures that when the fibers are reset during pressing, they stay that way.

 · Digital hygrometer/thermometer – to monitor temperature and humidity.

· Dehumidifier or humidifier – to keep relative humidity steady around 40–50%.

· Stable room temperature (70–75°F) – avoid hot attics, garages, or damp basements.

· Air purifier– keeps dust and particles away from books during cleaning and pressing.

· No direct sunlight – sunlight can cause heat fluctuations and fade inks.

· Climate consistency – don’t move books in and out of humid vs. dry spaces during pressing.

· Avoid “problem rooms” – open loft areas, high foot traffic zones, kitchens, bathrooms, and laundry rooms all cause big swings in humidity and should never be used for pressing or storing comics.

 After pressing, the paper fibers of a comic are in a “reset” state. They’ve been relaxed and flattened by heat and pressure, but they need time in a stable environment to fully settle. If you rush a book straight to grading or toss it back into an unstable storage space, you risk defects slowly returning.

Here’s what we recommend:

· Cooling/Settling Period: Let your freshly pressed book rest for at least 24–48 hours in a controlled environment before bagging and boarding. This allows the paper fibers to stabilize naturally at room conditions. Some advanced pressers give high-value books a full 3–5 days before handling or shipping.

· Environment: Keep the book in a 70–75°F room with 40–50% RH (same as your pressing setup). Avoid humid basements, hot attics, or rooms with fluctuating air conditions. Stability is the key to preventing reversion.

· Flat, Supported Storage: Store the comic flat between clean, dry backing boards (no pressure, just support) or inside a bag and board with a full-size backer. Some collectors stack a light, even weight (like another flat board) on top to encourage the book to stay flat while it settles.

· Avoid Immediate Shipment: Mailing right after pressing is risky — comics can be exposed to heat, humidity, or pressure during transit, which may undo your work. Waiting a few days before packaging helps the fibers “remember” their pressed state.

· Longer Holds for Problem Books: If the comic had severe waves, stacking curls, or stubborn dents, give it a bit more rest — up to a week — before grading. Patience here means better long-term results.

· Simple press (minor bends/waves): Wait 2–3 days.

· Heavy press (major ripples/curls): Wait 5–7 days.

· Always ship in stable climate: Avoid mailing during extreme hot or humid weather if possible.

 Use the pressure adjustment knob for pressing books at the correct pressure.  

1. Counterclockwise reverses pressure. Clockwise increases pressure.

2. Control adjustment knob with main hand.

3. PRO TIP: Use weak handto press handle clamp down. 

4. Your weak hand should easily lock in the closed position. If there is resistance, turn knob counterclockwise.

5. It takes time and practice to master this technique through experience. 

6. Always use light pressure on the clamp.

Do not turn adjustment knob while press machine is in the closed and lockedposition. 

 It should be noted that on most dry mount press machines, the adjustment knob located at top center of unit has 2 adjustment knobs. The larger outside knob you will turn counterclockwise to loosen the inside smaller knob. The inside smaller knob you will turn counterclockwise to increase pressure. You will turn the lower outside knob clockwise to tighten up the inside smaller knob. It’s the opposite of how a clamshell and swing arm press machine operates.

INTERIOR PAPERSTOCK (INTERIOR PAGES OF BOOK)

· 65 LB CARDSTOCK PAPER (Primary stacking layer, underneath covers or after pages 1 or 2)

· 110 LB CARDSTOCK PAPER (Staple protection, insert protection)

· 20 LB INKJET COPY PAPER (Secondary stacking layer, underneath covers or after pages 1 or 2)

· SILICONE RELEASE PAPER (Dent removal, before any insert envelope adhesive backing strip)

· NONE  (Reset underhanging covers)

CENTERFOLD PROTECTION (CENTER OF BOOK)

· MAGAZINE-SIZE BACKER BOARD (Single)

· TWO MAGAZINE-SIZED BACKER BOARDS (Double)

· FULL-BACK (Substitute for using two magazine-sized backer boards)

· 65 LB CARDSTOCK PAPER (Prestige Format, Squarebounds, Giant Sized glued spines)

EXTERIOR PAPER STOCK (OUTSIDE BOOK COVERS)

· 20 LB INKJET COPY PAPER (All press stages on all comic books and magazines)

· SILICONE RELEASE PAPER (Dent removal)

· 110 LB CARDSTOCK PAPER (Die cut covers, gimmick covers, embossed covers)

EXTERIOR CARD STOCK (OUTSIDE BOOK COVERS)

· MAGAZINE-SIZE BACKER BOARD (Top and bottom outermost stacking layers)

INSERT PROTECTION (BEFORE AND AFTER EACH INSERT PAGE)

· 65 LB CARDSTOCK PAPER (Recommended for most inserts)

· 110 LB CARDSTOCK PAPER (Recommended for DC Comics digital code squares)

· 20 LB INKJET COPY PAPER (5 sheets, if you do not have 65 lb cardstock paper)

EXTERIOR RIGIDITY (OUTSIDE THE EXTERIOR CARD STOCK LAYERS)

· STAINLESS STEEL PLATES (x2) (All press stages on all comic books and magazines)

· ALUMINUM PLATES (x2) (All press stages on all comic books and magazines)

· ½” or ¼”  THICK FOAM BOARD (Flattening spines – cover side down, staples up)

· THREE MAGAZINE BACKER BOARDS (x2) (Recommended if you don’t have plates)

Place the book cover with the most defects facing up towards top platen of press machine.  Most books do not require flipping. Thicker books like magazine sized comic books will require flipping and repeating Basic Press, due to the slow transfer of heat to the other side of book. If flipping is required, place the book cover with the most defects facing down first before the flip/repeat.

WHEN TO FLIP BOOKS, AND WHY

Most 32-page comic books do not need to be flipped (unless there are a lot of defects on both covers). Plenty of heat exchange permeates from the top cover through the whole book to the bottom cover within 10-15 minutes of heat. Certain books require flipping and repeating the heat press cycle process to properly heat the other side of the comic book. When dealing with a stacking curl, you place the book in press machine first with the bend facing up towards the top platen (typically, the front cover). When the first heat cycle is done and you flip the book, now the stacking curl bend is facing down.  You do not have to replace all the interior stacking layers during the flip. We do this so when the book is in a state of cooldown in the press machine for 18-24 hours, this keeps the bend facing down the longest while the paper stabilizes in its new position. Do keep in mind that these books may have to be repressed a second or even a third time for truly stubborn bends or folds when dealing with thicker binding. 

Let’s review which types of books should be flipped to repeat the heat cycle on the other side of the book:

· Comics with a large number of various defects on both covers

· Comic books that exceed 32 pages

· Stacking Curls (any)

· Squarebound glued and/or stapled spines

· Magazine-sized comic books

· Prestige Format graphic novel comic books

Sometimes a comic becomes oversaturated—either from improper humidification, storage in damp conditions, or accidental water exposure. Oversaturation causes the paper fibers to swell unevenly, creating rippling across the cover and pages, often most visible along the spine as spine waves. These defects make the book look warped and unstable, and if not corrected properly, they can return even after pressing.  

For all cold pressing, make sure you are using aluminum, galvanized, or stainless-steel plates to prevent rust from forming. Rust will appear on the book and your plates when using normal cold rolled steel plates.

1. Controlled Oversaturation (12–24 hours)

“Fight fire with fire.” Place the comic back into a humidity tank with a gallon of boiled water for 12–24 hours. This step may sound counterintuitive, but the goal is to re-soften the paper fibers evenly throughout the book. By bringing the book to a uniformly pliable state, you “reset” the paper, making it easier to reshape.

2. Cold Press (48 hours)

Transfer the oversaturated book directly into the press machine with interior stacking layers and press without heat for 2 full days. Cold pressing allows the fibers to slowly flatten under pressure while excess moisture dissipates gradually. Because no heat is applied, the fibers are not “sealed” too soon—this gives them time to relax and bond back into a flat, permanent position.

3. Final Humidity Tank (1 hour)

After the cold press, return the book to the humidity tank for a short 1-hour session. This re-introduces a mild level of flexibility into the fibers, preparing the comic for the final press.

4. Normal Heat Press (24 hours)

Perform a standard heated press and afterwards leave the book in the press machine for 24 hours before removing. This final step locks the flatness into place, sealing the fibers and ensuring the rippling and spine waves do not return.

Cold pressing works because it gives time for the paper fibers to realign and compress evenly under pressure, without the sudden expansion and contraction that heat can cause. When a book is oversaturated, applying heat too early can trap moisture, create new waves, or even damage the foil and inks. By pressing cold for an extended period, the fibers dry flat and stabilize naturally. Then, when you follow with a normal humidification and heat press, the fibers are already “trained” to stay flat — making the fix permanent. To learn more about the procedure, read Comic Book CPR: First Edition in Chapter 17 and follow the instructions for “Oversaturated Books”.