Tips of the Trade

Problem	Probable Cause & Suggestions
BLINDING Parts of image not printing	1. Weak or worn image on plate. 2. Ink dried on plate 3. Dampener solution too acid 4. Plate or blanket over packed 5. Form roller setting too heavy
CATCH-UP Radial band of ink in non-print areas.	1. Not enough dampener solution 2. Dirty or dry dampener rollers 3. Ink form roller(s) are set too tightly on one end.
COLOR MATCHING Printed piece does not match proof / colors have incorrect hue.	1. Color Sequence on Quad Stack not correct ~Station all inks from the bottom deck CMYK. This typically corrects reds that look orange and better predicatable flesh tones. 2. Ink pigment may be too strong in a particular color ~Contact ink manufacturer, ask to test different strengths of each color
DOT GAIN / PRE-PRESS Unable to match proofs, halftones appear plugged. (See also dot gain / press)	1. Plate over exposed. ~Check exposure / use stouffer scale 2. Film has low D-max ~Set output device to acheive proper manufacturer film D-max 3. Poor or indadequate vacuum in plate burner ~ Check plate burner frame from vacuum leaks / vacuum pumps are working to peak volume. Allow ample time for vacuum to pull negative to plate - 20 seconds 4. Poor film quality ~Soft dot film vs. hard do film can make a difference. 5. No dot gain curve has been applied to output device to accommodate for normal press gains. ~Conduct output device linerization to press and measure dot gain per tint step; apply this data to the output device as a curve.
DOT GAIN / PRESS Tones appear muddy / image lacks sharpness	1. Ink densities too high ~Set inks according to SNAP specs for either newspaper or commercial printing 2. Too much dampener ~Reduce water dial until non-image areas take on ink; take water down a little at a time 3. Incorrect blanket packing ~Check and adjust to proper blanket height 4. Poor ink body / low viscosity ~Try a stiffer ink 5. Glazed blankets ~ Use a deglazing solvent to remove varnish or replace blankets 6. Ink rollers out of adjustment or set incorrectly ~set ink stripes to WPC specs - 3/16" - 1/4"
FILL-UP Type or halftone screens plugging with ink	1. Too much ink. 2. Greasy or dirty ink. 3. Form roller settings too heavy 4. Plate and blanket over-packed. 5. Not enough dampener solution 6. Worn plate (check plate surface for scratches, burnishing).
GRAININESS Grainy, gray or weak printing	1. Not enough ink. 2. Not enough impression. 3. Glazed blankets 4. Weak or worn image on plate 5. Weak ink 6. Form roller setting too high
INK CONTAMINATION Color inks seem to get contaminated from another color during production.	1. Ink keys not shut off outside the printable area of the web allowing excess ink to travel from blanket to blanket into each deck ink rollers and ink fountain. ~Before press start preset ink keys to web width and plate image area to eliminate excess ink from traveling to other decks. 2. The spray interrupts on the water baffle are open beyond the web width allowing excess water to mix wtih ink pigment and to travel deck to deck. ~Close spray interrupts where web width ends. Closing the interrupt halfway at the edge of the web will also help ink/water balance of print on the edge of the web
INK EMULSIFICATION / WATER LOGGING Print appears splotchy in tones / areas do not accept ink	1. Unable to set even densities across sheet. Ink leaving splotches on sheet ~Check ink rollers, make sure stripes are set correctly. Inspect ink oscillator roller, make sure that it is moving from side to side. 2. Accumulation of water in ink fountain. ~Check ink rollers / dampener roller settings, adjust if needed. Reduce water feed. 3. Conductivity too high ~Reduce concentration of fountain solution, bring conductivity down.
LINTING Accumulation of paper fibers building up onto plates, blankets, and/or ink rollers	1. Ink too tacky for paper stock ~Consult ink manufacturer to adjust ink for less tack. 2. Too much water reaching paper during operation ~Adjust for lowest possible ink and water balance 3. Improper concentration of fountain solution ~Check conductivity and adjust fountain solution according to manufacturer specs over tap water 4. Improperly packed blanket heights ~Check and repack blanket cylinders to correct height. Low cylinder height will increase linting problems 5. Excessive lint on newsprint ~When possible, reverse direction of roll unwind; consult paper manufacturer.
MOTTLING Solid areas not uniform in density / colors apear splotchy	1. Incorrect ink / water balance ~Adjust ink & water for proper balance, remember less is best. 2. Improperly set rollers, glazed or worn & hard rollers ~Check and adjust roller stripes, check durometer of roller for excessive hardness, deglaze or replace bad rollers. 3. Improper blanket-to-blanket or plate-to-blanket settings and blanket height. ~Check blanket and packing height for proper specs and check cylinder settings, adjust if needed.
PICKING AND HICKIES White spots on solid areas and black spots in white areas or printed page. (See also "Linting" and "Rub-off")	1. Ink too stiff or tacky, pulling particles of paper from the web. 2. Excess lint on paper stock. 3. Foreign particles in ink. 4. Dirty inking or dampener rollers. 5. Dirty blankets. 6. Tacky blanket surfaces.
POOR / WEAK SOLIDS Gray / weak solids that lack density or color lacks lift.	1. Low Blanket Height ~Repack blankets ot proper height 2. Incorrect plate-to-blanket & blanket-to-blanket settings ~Check and adjust settings that are not to WPC specs 3. Glazed / polished blanket surface ~Use a deglazing solvent to remove varnish or replace blankets 4. Incorrect ink and water balance ~Adjust ink and water to a minimum without scumming 5. Too much fountain solution ~Adjust concentration in water tanks / check conductivity & set to recommended amount over tap water.
REGISTRATION PROBLEMS Difficulty in alighning separations; side-so-side register / fan-out	1. Web tension ~Adjust reel so that dancer roller is lifted off of block. Be sure that spring has enough tension applied so that cable is taut. Set a web guide roller to a stationary position and back off brake - this will help prestretch the web before entering the unit. 2. Too much water; web stretching. Wet sheet coming off folder ~Reduce water feed 3. Blanket compatibility ~Blankets may not be compatible with equipment. Some testing may be needed if you change suppliers. A 3-ply comopresible works well with the Quad-Stack. 4. Web wrinkles / creasing ~Loosen reel brake some ~high moisture content in paper (talk to supplier) ~clean web guide rollers 5. Not enough pull out of equipment to folder ~adjust trolleys and nippers to accomodate even web draw. Inspect trolleys and nippers and replace if worn.
ROLLER OVERSPRAY / MISTING Excessive amount of ink splattered inside roller pans	1. Improperly set, hard, or worn ink rollers ~Check roller stripes, roller durometer and flared rollers. 2. Improper ink and water balance ~Adjust for proper balance, less is best 3. Ink viscosity too low ~Check with ink manufacturer for better formulation regarding this problem 4. Improper fountain solution concentration ~Check conductivity and adjust fountain solution according to manufacturer specs over tap water 5. Excessive ink on rollers ~Check print with densitometer and adjust if ink keys were too high.
RUB-OFF Accumulation of paper fibers building up onto plates, blankets, and/or ink rollers	1. Incorrect ink & water balance ~Adjust press for proper balance, less is best 2. Ink densities too high ~Check printed piece with densitiometer, adjust press where needed to carry less ink 3. Improper concentration of fountain solution ~Check conductivity, adjust fountain solution concentration accordingly. 4. Poor maintenance; rollers, blankets, & impressions ~Devise good maintenance practices. Stay on schedule according to usage per manufacturer's specs. 5. Non absorbent stock ~Consult paper supplier / manufacturer 6. Not using a low-rub ink ~Consult ink supplier for low-rub inks
SCUMMING Areas of non-printed surface taking ink For more indepth discussion of scumming issues when moving from a narrow web to a wider one, please visit the following forum page: click here	1. Incorrect ink & water balance ~Adjust for proper balance. Less is best 2. Poor water system maintenance ~water tray has debris in it blocking pan roller from picking up water ~Thoroughly clean water system by removing water baffle and wiping water pan clean 3. Spray interrupt closed in area(s) that are scumming ~Be sure (during make-ready) that the spray interrupts have been adjusted to the web width 4. Bad brush or pan roller bearings. Brush roller may wobble causing loss of contact ~Replace bad or worn bearings as needed 5. Brush roller not making sufficient contact with pan roller ~Adjust eccentrics on brush roller to correct specs, check along entire roller: look for worn bristles; replace brush of required. 6. Improper concentration of fountain solution ~Check conductivity and adjust fountain solution according to manufacturer specs over tap water. 7. Poor plate storage; plates exposed to extreme heat, moisture or light ~Store plates in a cool, (not below freezing), dry and dark condition. 8. Poor hard rollers / incorrectly set rollers ~Adjust rollers to proper stripes and check roller hardness with durometer; replace if necessary
SHOW THROUGH / OFFSETTING Reverse side of printed page visible	1. Insufficient opacity in newsprint ~Change to more opaque newsprint, talk to paper supplier 2. Impression too heavy / blanket height incorrect ~Adjust impression to correct specs and check blanket height for proper packing height. 3. Ink limits (TAC) set too high from pre press ~Set TAC, total area coverage, to the 220% - 240% range for separations 4. Ink densities set too high ~Set densities to SNAP specs and use a densitometer.
SLURRING / DOUBLING Bands of blurred image appearing across Web. Print appears blurred on leading or trailing edge of image	1. Improper dampener solution. 2. Ink dried on plate. 3. Blanket under or over packed. ~Check blankets at each deck for proper blanket torque 4. Form rollers incorrectly set. 5. Roller sprockets or bearings worn. 6. Loose blanket 7. Web guiding roller not turning freely 8. Too much brake at the reel, dancer roller bottomed out ~Loosen brake so that the dancer roller is free. 9. Dancer roller is surging up and down ~Caliper shoes may be glazed; remove and rough up surface, have turned down or replace 10. Web guide rollers not turning freely ~Check for bad bearings and replace 11. Bearers too tight ~Check that all bearers on each deck are set to 1/32" with aluminum foil.
STREAKING Streaks appearing across the web.	1. Ink form rollers set too lightly. 2. Hardened or glazed form rollers, use Varn "Revital" or equivalent to renew surface. 3. Poor balance between ink and dampener solution. 4. Improper pressure setting.
STRIPPING Uneven printed image, rollers refusing to take image. (See also "ink emulsification")	1. Inking roller glazed. 2. Dampener solution too strong and emulsifying ink. 3. Improper ink formulation. 4. Incorrect roller setting.
TINTING / TONING Light tint or wash appearing over the entire sheet. Emulsified ink transferred to the sheet appearing gray or tinted.	1. Improper concentration of fountain (dampener) solution ~Check conductivity and adjust fountain solution according to manufacturer specs over tap water. 2. Improper ink & water balance / excessive ink and water will emulsify in ink train ~Adjust ink and water balance to minimum for optimal print 3. Thin ink / ink bleeds into water fountain ~Cunsult with ink manufacturer 4. Improperly stored plates ~Store plates in areas of low humidity 5. Improperly coated or developed plates. ~Test plate processing by running an unexposed plate through processor and then expose plate with negative on burner, burn the plate 3 times longer than normal. Then reprocess the plate, look for an image appearing. If image is visible, the plate is most likely the cause. ~Check chemistry in processor / replace, slow down processor to allow longer developtment time. Contact plate supplier. 6. Improperly set ink rollers. (Rollers that are set too tight can create this problem) ~Set ink stripes throughout the ink train to the proper setings - 3/16" - 1/4". 7. Check local water supply.
LOOSE WEB Web runs loosely between unit and folder	1. Ink too tacky. 2. Blankets over packed. 3. Lint builds up on blankets. 4. Nipping rollers set too loose. 5. Trolleys set incorrectly. 6. Not enough brake.
WEB BREAKS Web breaks during start up or normal operation of machinery	1. Too much dampener solution during start-up. ~Turn down main water control so that water doesn't gather at the plate gap. 2. Web tension incorrectly set / reel brake set too tight ~Back off the brake so that dance roller has free movement. 3. Blankets incorrectly installed ~make sure tha all blankets are installed on the cylinder with the same arrow direction as indicated on the back of the blanket. 4. Faults in paper ~Contact paper supplier
WEB OVER-FEED Difficulty in maintaining even web alignment into folder / weboiverfeed between decks	1. Web tension Adjust reel so that dancer roller is lifted off of block. Be sure that spring has enough tension applied so that cable is taut. Set a web guide roller under QS to a stationary position and back off brake. 2. Blanket compatibility ~Blankets may not be compatible with equipment. Some testing may be needed if you change suppliers. A 3-ply compressible works well with the Quad-Stack. 3. Blankets not torqued down correctly on each deck (QS) ~Check blankets for proper torque, feel blanket as it bends into the gap - you shouldn't feel "air" gap between blanket and cylinder, if so, adjust torque. 4. Not enough pull out of equipment to folder ~Adjust trolleys and nippers to accomodate even web draw. Inspect trolleys and nippers. Replace if worn.

TIPS OF THE TRADE