Implementing Fm Screening

The foundations of successful FM screening implementation include the next steps:

1) Make surely that everyone inwards the store that is involved amongst impress sales together with production understands why the companionship is changing the impress process. All should wishing the alter to succeed together with should catch a payback specific to their area. Sales volition withdraw hold a novel story to say almost the company's powerfulness to come across buyer expectations. Prepress together with pressroom volition hold upward able to stabilize together with optimize their areas. Management should catch a clear differentiator, reduced manufacturing costs together with to a greater extent than consistent product.

2) Make surely that the plates withdraw hold the resolution to back upward FM at the chosen micron size (typically 20-25 micron for full general commercial, 25-35 micron for publications together with newsprint). Contact your local service or sales representative for the electrical flow listing of qualified media.

3) Make surely that your CtP has the capability to create FM at the chosen micron size. Again, contact your local service or sales representative.

4) Communicate your intent to impress FM amongst your ink vendor. Ask them almost the ink serial you lot are using together with whether it is appropriate for FM. They may advise a dissimilar serial based on their experience. If they don't withdraw hold sense amongst FM, so involve them inwards your initial start upward together with learning. If they are non interested so start looking for a dissimilar ink vendor.

5) Your store should withdraw hold an existing reliable together with consistent impress manufacturing process. I.e. the press is non used equally a color correction device. One uncomplicated seek is to withdraw hold the press operator create their brand fix without seeing a proof. In a good run shop, the press tin displace hold upward brought upward to color together with when so compared to the proof at that topographic point volition hold upward real piddling difference. If the press operator is lost without the proof so that mightiness dot that the procedure is non stable together with inwards control.

6) Build dot gain curves to hold upward applied to plate imaging to convey note reproduction inwards work amongst your electrical flow AM/XM printing.

7) Optionally, fine melody your proofing so that it reflects the extra gamut you'll catch amongst FM.

8) Make FM your criterion screening - non an exception for special projects. The finish should hold upward that AM/XM screening solely hold upward used for special applications similar reprints. That agency the press operator gain sense together with agreement of how FM reacts on press compared to what they are currently familiar with.

9) If you lot withdraw hold to a greater extent than than i press/press crew - withdraw i to hold upward your pioneers together with champions of FM printing. They tin displace so instruct the other crews the keys to their success.

Generally, most of the problems encountered amongst implementing FM screening resultant from impress store civilization - non the technology itself.

Fountain Solutions
Due to the over all pocket-sized dot sizes, ink together with H2O residual is to a greater extent than critical amongst FM screening (and real high lpi AM/XM screening) than amongst conventional AM/XM screens at manufacture criterion lpis. So, earlier switching to FM screening, you lot should resolve whatever ink together with H2O issues you lot withdraw hold amongst your electrical flow screens.

There are no laid rules almost outpouring solutions together with FM, except to go a proficient production that is recommended yesteryear your ink together with plate manufacturer. In general, less is best. Where possible, run the minimum dosage inwards your outpouring solutions that the manufacturer recommends.

While FM microdots are less sensitive to physical dot gain from over-inking, they are to a greater extent than sensitive than the larger AM/XM dots to surrounding H2O levels together with outpouring conditions. Therefore, it is of import to command pH, temperature, conductivity, together with contamination inwards the H2O pick-up tray together with on the chrome or ceramic pick-up rollers. The temperature of the outpouring tin displace hold upward controlled inwards the re-circulation organisation (keep inwards heed that temperature inwards the tray may hold upward v to 10 degrees warmer). Fountain temperature should hold upward controlled inside 0-5 degrees of manufacturer’s specification. Temperature tin displace hold upward farther controlled inwards the press, using chilled rollers. Buffered outpouring solutions assistance to stablize pH levels; however, pH should silent hold upward measured periodically to ensure that it stays inside the manufacturer’s specifications. Processed H2O is recommended to farther stabilize electrical conductivity together with pH. Check amongst your supplier to detect a H2O handling organisation suited to your printing needs.

H5N1 surely flat of ink contamination inwards the outpouring is unavoidable; however, excessive contamination is an indicator of other issues. In fact, it may outset hold upward noticed inwards your presswork equally all-color "rain," or H2O streaking. Look for excess ink coming dorsum through the roller train. This is sometimes referred to equally chrome roller feedback, pick-up, ink belled dorsum or opposite emulsification. Numerous factors bear on this condition, including temperature of ink together with fountains, emulsification, press speed, together with the status of the H2O pick-up roller. Simple remedies include improve maintenance of chrome roller surface (no micro-cracks), temperature control, together with desensitizing the chrome roller to improve the H2O pickup together with go along ink away.

Back trap piling inwards the non-image expanse of the plate or blanket is mostly caused yesteryear excessive ink inwards the fountain, depression conductivity, together with non-image expanse that is non desensitized – attracting ink instead of repelling it amongst water. Remember that outpouring solution is a mild solvent. As such, if it is over aggressive it may overpower the ink celluloid on the microdots together with drive a loss of ink density.

Alcohol together with alcohol substitutes assistance lower surface tension together with ink viscosity, which promotes improve unloosen of FM's microdots. The amount of alcohol together with alcohol substitutes used volition depend on environmental restrictions inwards each locale.
When implementing FM screening it sometimes helps to persuasion the screening inwards the context of AM/XM halftoning. There are 2 basic ways to aspect at how they compare.

The outset is related to their resolution, or particular rendering equivalency. That is ordinarily determined yesteryear running a work diagonally through the FM covert together with so measuring the number of dots per inch along that line. The to a greater extent than dots per inch that the work intersects the higher the effective lpi.

The instant is their lithographic equivalency. Basically how the FM covert reacts on press to ink, water, etc. That is ordinarily determined yesteryear counting the number of transitions (dot edges) inwards a given covert note expanse together with comparison that to the number of transitions inwards the same note expanse inwards an AM screen.

Here are the numbers for several pop FM dot sizes - micron size compared to lpi:

Detail rendering equivalency:
FM twenty = 500 lpi
FM 25 = 325 lpi
FM 35 = 325 lpi
FM 36 = 275 lpi

Lithographic equivalency:
FM twenty = 385 lpi
FM 25 = 240 lpi
FM 35 = 240 lpi
FM 36 = 205 lpi

The higher upward equivalencies are for a typical instant lodge FM covert - i that, unopen up, looks similar this:The vast bulk of FM screens inwards go today are instant lodge using similar dot patterns so the equivalencies should hold upward unopen plenty for practical application. These equivalents are non absolute values since they volition differ somewhat according to the pattern of the specific covert together with how the engineer calculates equivalency.


Curve Management
The dot gain characteristics of FM require the application of dot gain compensation curves to plates. For predictable tonal answer on press, go along the mechanical together with chemic weather on your press good maintained, together with solely create tonal compensation curves when the press is inwards a stable status for your electrical flow AM/XM printing.

The basics of edifice tonal compensation curves to align your AM together with FM presswork

1. This volition withdraw 2 press runs - i to acquire information for your electrical flow screening, together with the instant to acquire the answer of the FM screening. If you lot withdraw hold confidence inwards your electrical flow AM/XM presswork you lot may withdraw to solely create the FM screening pressrun together with compare the values it delivers to the target tones of your AM/XM presswork.
2. Your press should hold upward inwards a stable status that accurately reflects your pressroom environment, including documented criterion ink density (SID) for your shop.
3. Your existing AM/XM presswork should hold upward the tonal target for your FM screened presswork.
4. Image plates for your AM screening using whatever plate curves you lot currently apply.
5. Image plates for your FM screening without applying whatever plate curves (uncalibrated plate).
6. Bring your presswork to to criterion solid ink densities.
7. Pull several proficient sheets together with stair out the CMYK note scale answer of the AM/XM together with FM screens. The to a greater extent than sheets you lot
measure, the to a greater extent than representative the average volition hold upward of your printing conditions.
8. Use the measured information to create tonal compensation curves for your FM presswork.
9. Set upward your RIP together with workflow to deal the application of the FM curves.
10. Create together with impose a seek target for you lot FM presswork to confirm that the workflow has ikon the plate amongst the right dot gain compensation curve.
11. Go dorsum on press for a verification run to confirm that the curves for the FM screening are correct. Make adjustments equally required.

Color Management
You may optionally create upward one's heed to profile your FM presswork inwards lodge to reverberate the added FM gamut so that your proofs are a closer check to your presswork.
1. To color deal a proofing device, create profiles yesteryear characterizing your FM presswork proofs amongst ICC targets or equivalent.
2. Gather the characterization information from your FM verification press run together with go the resulting measurements to create an ICC profile to hold upward used inwards a color-managed workflow to drive your proofer.
3. This is rarely done, however, if desired, you lot may withdraw to create a separation profile to convert RGB images to CMYK inwards lodge to withdraw wages of FM screening's larger gamut.

Image Management
1. When printing amongst FM twenty or FM 10 on coated paper on sheetfed together with spider web presses, scan at resolutions higher upward 300 dpi to withdraw wages of FM's powerfulness to homecoming together with capture real fine details together with texture. There is no involve to scan higher than 600 dpi.
2. When printing newsprint amongst FM 36 or FM 25, you lot create non involve to scan images higher than 300 dpi. Typically, images may hold upward scanned at resolutions equally depression equally 150 to 200 dpi. To determine the lowest resolution at which you lot could scan images together with impress successfully, create a press test. When the resolution is likewise low, you lot may catch stair casing unopen to the edges of ikon objects.
3. Make surely that images are non downwards sampled when going from native file applications to PDF.4. Make surely that at that topographic point are no settings inwards the RIP that volition drive images to hold upward resampled at a lower resolution.

The Pressroom

Presses
Older coldset webs may withdraw hold problems amongst FM screens together with AM/XM screens finer than 110 lpi. Dampening systems running bareback amongst a durometer reading harder than 34 may withdraw hold difficulty running FM.

Older presses amongst conventional dampening systems that go covers, sleeves, socks and/or wraps anywhere inwards the organisation may detect that the increased particular resolution of FM results inwards the cloth weave/grain of the dampener stuff beingness resolved on the press sheet.

Older webs that tin displace run 133 lpi screens tin displace run 35 micron FM together with coarser, spell older webs than tin displace run 150 lpi screens tin displace run 25 micron FM together with coarser. Older webs without an in-feed tin displace also run 35 micron FM. In-feeds are of import for spider web command together with tin displace cut back plate wear, spider web movement, together with linting.

On paper webs, printing on paper amongst a recycled content of 75% or greater may create problems because the paper carries a high amount of silica, which causes piling together with plate blinding.

Ink
For all press types, earlier using FM screens, beak amongst your ink supplier equally they may withdraw hold identified an ink serial that industrial plant best amongst this type of screening. Remember that it is non so much whether the screening is AM/XM or FM that's important, it's the size of the dots through the note scale that helps determine the formulation together with functioning of the ink.

When using 25 micron FM, you lot should hold upward printing amongst inks that flow good amongst 133 work AM screens, and, for twenty micron FM you lot should hold upward printing amongst inks that flow good amongst 175 work AM screens.

Ideally, FM inks should withdraw hold depression viscosity together with high flow. Low viscosity helps ink shear together with transfer to the sheet. Printers tin displace driblet viscosity yesteryear changing the paint vehicle (oil), yesteryear increasing the H2O pickup, or yesteryear increasing ink temperature. High-pigment, low-gain inks are problematic amongst FM screening because they withdraw hold a propensity to pile together with impress inconsistently.

Remember that each press is different. Settings together with inks that piece of work good on i press may non piece of work good on some other press.
1. Use progressive-tack equally opposed to common-tack inks for FM. Generally, you lot create non involve to alter ink tack values or sequence from those used amongst AM/XM settings.
2. Metallic together with fluorescent inks withdraw hold piteous transfer, fifty-fifty amongst conventional 175 lpi screens. The pigments inwards these inks are coarse, together with piddling tin displace hold upward done to improve the vehicle. Coarser screens such equally 25 or 35 micron FM are improve suited to these inks. Check amongst your ink manufacturer to catch what other options are available.
3. Some PMS colors (spot or special color) Pb to inconsistent coverage on sheetfed presses. For example, solid tints tin displace appear mottled or aspect similar the texture of an orangish peel, together with this tin displace impact FM covert tint builds. The paint inwards each PMS color tin displace vary considerably hence you lot should piece of work your ink manufacturer to optimize functioning for the dot size you lot are printing with. If mottle occurs, it may hold upward necessary to mill/refine/grind the ink a instant fourth dimension to cut back the size of the paint particles.
4. FM performs best on press when using lower levels of H2O together with only plenty ink to hit desired densities. Use H2O levels rather than ink density to command FM microdots. Adjusting density to command midtones should hold upward the exception together with non mutual practise amongst FM.
5. Generally speaking, 175 lpi sheetfed printers are typically good suited to run twenty micron FM amongst the inks they go for their AM/XM printing; however, these printers may silent involve to conform ink flow together with viscosity to optimize the ink for FM’s microdots.
6. Use low-viscosity, high-flow inks for heat-set webs. Chilled or water-cooled oscillators go along roller temperatures constant together with maintain ink viscosity together with functioning at ideal levels. If your press doesn’t withdraw hold this capability, inquire your ink manufacturer to assistance alter viscosity yesteryear altering H2O pickup or oil.
7. On spider web presses, go procedure dark ink instead of bulk dark inks where possible. Process dark ink
offers the best results amongst FM equally it behaves similar cyan, magenta, together with yellowish inks.
8. On heat- together with cold-set webs, bulk dark together with recycled dark inks withdraw hold piteous transfer rates, together with they behaviour to a greater extent than similar fluorescent together with metallic element ink. Book dark ink is typically used for high-density requirements spell recycled, dark ink is used inwards high-volume applications such equally publications, newspaper, flexography, together with packaging to come across terms together with environmental requirements.
9. Heat-set together with cold-set spider web inks are mostly suitable for 25 together with 36 micron FM together with typically create non require changes to formulation or vehicle.
10. For twenty micron FM on spider web presses, piece of work amongst your ink manufacturer to optimize performance.

Undesirable Patterns inwards Presswork
Proper press maintenance should hold upward the policy no affair what halftone screening is beingness used. However, the finer the covert the to a greater extent than critical proper maintenance becomes since the microdots used inwards high lpi AM/XM together with FM screens tin displace let on flaws inwards the presswork that were previously hidden yesteryear large AM dots.

Thin Lines inwards the presswork

Flaws together with grind lines on press rollers tin displace drive visible lines to appear inwards press piece of work when printing amongst fine AM/XM together with FM screens. They are characteristically oriented inwards the direction of paper go through the press.

Grind lines are imperfections inwards the prophylactic rollers caused yesteryear grinding inwards manufacturing together with habiliment on press. They demo upward equally night lines inwards the direction of paper go amongst a frequency of i to 4 millimeters. They tin displace hold upward seen yesteryear using a loupe together with examinging the solids. They are sometimes visible to the optic betwixt the 50% together with 75% FM tints. When H2O celluloid on press is likewise sparse to create total the grind together with habiliment lines on prophylactic rollers, the resulting H2O celluloid is uneven together with transferred to the plate. Under 200 lpi, the uneven H2O celluloid has piddling effect. However, finer screens tin displace homecoming inconsistencies inwards the H2O film, together with these flaws demo upward equally thin, night lines inwards the presswork.

Roller grind lines are typically establish on the water, form, or metering rollers. You tin displace visually monitor the lineament of H2O celluloid yesteryear examining your chrome rollers together with yesteryear examining your presswork. When at that topographic point are visible fine lines together with patterns on the chrome rollers, you lot withdraw hold inconsistent H2O transfer, together with the rootage tin displace hold upward either roller grind lines or overly sensitized rollers. White together with milky H2O celluloid on chrome rollers tin displace position overly sensitized rollers together with tin displace dot that the rollers involve desensitizing to assistance H2O displace smoothly through the press. Ask your press and/or ink vendor for a suitable desensitizing agent.

Short sparse "rain—lines" that vary over the canvass together with from canvass to canvass may hold upward caused yesteryear H2O lines. They tin displace hold upward establish inwards solids together with covert tints together with aspect somewhat similar a rainstorm. When H2O lines are dark, aspect for ink/water emulsification problems. When H2O lines are low-cal (looks similar lots of curt scratches), H2O together with ink levels are mostly likewise low.

Micro patterning together with micro detail

FM screening tin displace resolve both desirable particular inwards images equally good equally undesirable particular created at diverse stages inwards the reproduction process. In particular, fine artifacts such equally photographic grain, paper texture, together with ikon manipulation artifacts may non demo upward amongst 150 lpi screens but may hold upward resolved amongst AM/XM together with FM microdots. Careful analysis yesteryear measuring the pattern, frequency, together with angle of micro structures tin displace assistance position whether the rootage is screening, imaging, processing, or presswork. Rotating the plates together with images tin displace also assistance to narrow downwards the sources of unwanted patterns.

Mottle

Mottle results inwards botchy, uneven, apartment tints amongst an orangish tegument texture together with is most evident when you lot aspect at solids nether a loupe. Mottle may hold upward caused yesteryear ink breaking downwards making solids appear equally if the were printed amongst flexography. It is most commonly seen inwards Pantone Matching System colors amongst coarsely dry reason pigments. It’s also mutual amongst high paint loads when emulsification leads to uneven ink films beingness transferred to the sheet. Low H2O levels tin displace drive PMS colors to bleed inwards FM tints, leading to excessive gain together with farther mottle. Flat-tint mottles are peculiarly bad inwards blues, greens, together with element of group I browns.

Mottle tin displace also hold upward caused yesteryear the substrate if it does non withdraw hold a consistent ink accepting surface. Sometimes the paper's potential for mottle tin displace hold upward seen yesteryear asset the canvass upward to a low-cal together with seeing if at that topographic point is a blotchy lineament of shiny together with matte areas.

Run length

H5N1 few printers may sense shorter run lengths amongst FM screening on heat-set spider web presses (but non amongst positive plates or sheetfed presswork). This may hold upward the resultant plate habiliment or blinding. On negative plates, calcium carbonate crystals from the paper (two to iii microns inwards size) may accumulate on pocket-sized dots together with drive blinding - the plate ikon is visible on plate but does non send ink. The smaller dots inwards both AM/XM together with FM printing are also susceptible to paper piling, which tin displace exacerbate plate habiliment or drive blinding on poorly maintained spider web presses.