UPM finesse papers from Kymi mill in HSWO printing

- How the get the best out of UPM finesse in HSWO printing -

Content

page1 UPM Finesse papers ..............................................................................................2

2 UPM Finesse in pre press ......................................................................................3

Screening .......................................................................................................3

UCR or GCR, examples ................................................................................6

Print densities and ink demand .....................................................................9

3 Drying of UPM Finesse in HSWO ......................................................................10

4 Printing materials .................................................................................................13

Printing inks.................................................................................................13

Fountain solution ........................................................................................14

Printing blankets and plates........................................................................15

5 Conditioning and handling of paper.....................................................................16

6 Web tension in printing........................................................................................18

7 Directive recommendations for UPM Finesse matt..............................................19

8 Directive recommendations for UPM Finesse gloss and premium silk................20

9 Summary of directive recommendations for UPM Finesse WFC papers.............21

edited 21.12.2008 Teuvo Leppänen & Stéphane Petit-Gras

page 1

1 UPM Finesse papers from Kymi mill

UPM Finesse from Kymi mill is a wood free coated paper with different finishing differing by paper gloss, surface smoothness and basis weight. "Wood free" means that only chemical fibres are used in furnish of paper, assuring the high brightness and archiving properties of paper, besides the needed strength properties and surface properties assuring a good printability in HSWO. UPM Finesse is coated with blade doctoring and with several coating layers giving high smoothness and evenness of paper surface. UPM Finesse papers and their technical specifications are presented in Table 1.

Table 1. UPM Finesse reel grades from Kymi mill and their technical specifications.

Paper gradebasis weight g/m²

Gloss Hunter (%)

Brightness D65 (%)

Whiteness CIE (%)

Opacity ISO (%)

Bulkcm3/g

Roughness PPS10 m

UPM Finesse gloss8090

100115130150

656668686868

989898989898

130130130130130130

92.593.595.096.097.098.0

0.800.800.800.800.800.80

1.01.01.01.01.01.0

UPM Finesse premium silk8090

100115130150

404042444444

989898989898

130130130130130130

93.594.596.097.098.099.0

0.840.840.840.840.840.84

2.02.02.02.02.02.0

UPM Finesse matt8090

100115130

2023242425

9797979797

130130130130130

93.095.096.097.098.0

0.850.850.850.850.85

2.42.22.22.22.2

The main differences in papers, besides the basis weight, are gloss and roughness. The premium silk and matt grades have higher opacity than glossy papers in the same basis weight due to the better light scattering (non-glossy papers are also bulkier).

page 2

2 UPM Finesse in pre press

Screening

UPM Finesse is relatively high in ink setting speed, which has the benefit of low dot gain in printing, which again makes high print contrast and good detail rendering possible. Too high ink setting speed of paper (with quickly setting printing ink) can increase the tack of ink in printing nip and cause picking and it can increase the risk for back-trap (carry over) piling, especially if the printing speed is low enough.

Dot gain of UPM Finesse grades (CMYK average)60 lpcm round dot in 20% and 70%, square in 50% -

MurrayDavies equation

0

10

19

12

00

13

22

16

00

16

26

22

00

5

10

15

20

25

30

0 10 20 30 40 50 60 70 80 90 100

dot area%

do

t g

ain

%

UPM Finesse gloss

UPM Finesse premiumsilk

UPM Finesse matt

Fig. 1. Average dot gain of CMYK tones for UPM Finesse papers from Kymi mill.

The dot gain in 50% halftones in each primary colour with UPM Finesse grades are presented in Fig. 2 (the average dot gain in 50% halftone in Fig. 1 is from this). The dot gain can be increased if the feeding of fountain solution is high (printing ink has high emulsification rate). UPM Finesse Gloss is the most sensitive for increased dot gain with high amount of dampening "water" feed, because it has low water absorption properties. UPM Finesse gloss and UPM Finesse Premium Silk in some extent are also sensitive for uneven printing in the form of water repellance mottle if the feeding of fountain solution is high. This can happen especially in the cases where printing inks have low emulsification rate and extra water feed causes film water on the surfaces of ink forme rollers or on the printing plates.

page 3

Dot gain of 50% halftones

1922

26

1922

26

1720

2421

24

28

1922

26

0

5

10

15

20

25

30

UPM Finesse gloss UPM Finessepremium silk

UPM Finesse matt

do

t g

ain

%

cyan

magenta

yellow

black

average

Fig. 2. Dot gain of 50% halftone areas for UPM Finesse papers from Kymi.

The screen rulings to be used for different UPM Finesse grades are determined by the dot gain. The recommendations for the screen rulings with AM screening and with round dots are:

UPM Finesse gloss 70 - 80 lpcm (180 - 200 lpi)UPM Finesse premium silk 60 - 70 lpcm (150 - 180 lpi)UPM Finesse matt 54 - 60 lpcm (140 - 150 lpi)

With the presented dot gains and screen rulings the printable tone areas of primary colours with UPM Finesse papers are:

UPM Finesse gloss 3% - 97%UPM Finesse premium silk 3% - 96%UPM Finesse matt 4% - 96%

If the red hues (skin etc.) do not require otherwise, the screen angles should be as close as possible to the rational angles of 15°/75° (cyan/magenta), 75°/15° (magenta/cyan), 0°(yellow) and 45°(black) in order to form a regular rosette and avoid moiré patterns in neutral grey tones (see Fig. 3).

If there are needs for proper colour rendering without moiré patterns in reddish and brownish (skin) tones, then the following screen angles should be used: cyan 15°/75° - magenta 45° - yellow 0° - black 75°/15°.

page 4

Fig. 3. Traditional screen angles for a regular rosette in printing.

The dot gain in UPM Finesse is different when stochastic screening is used. With 20 micron sized dots the average dot gain change in FM screening compared to dot gain with AM type of screening are for UPM Finesse papers:

- in 20% halftone +4% higher dot gain than with AM screening- in 50% halftone -2% lower dot gain than with AM screening- in 70% halftone +3% higher dot gain than with AM screening

If the stochastic (FM) screening is used, then the control of screening is done with the pixel size or resolution used in exposure of printing plate in CTP. The typical dot size to be used in FM screening with different UPM Finesse papers can be calculated on the basis of screen rulings used in AM:

PaperAM screen ruling, lpcm

FM pixel size (microns) with 16x16 dither matrix

FM pixel size (microns) with 8x8 dither matrix

UPM Finesse gloss 70 9 18UPM Finesse premium silk 60 10 21UPM Finesse matt 54 12 23

The dot gain curves with FM screening and UPM Finesse will come later because of lack of information at the moment. There is some directive information about the dot gain of UPM Finesse papers in FM screening compared to AM screening:

PaperDot gain in AM 20% halftone

Dot gain in FM 20% halftone

Dot gain in AM 50% halftone

Dot gain in FM 50% halftone

Dot gain in AM 70% halftone

Dot gain in FM 70% halftone

UPM Finesse gloss 10 12 19 21 12 15UPM Finesse premium silk 13 17 22 25 16 21UPM Finesse matt 16 22 26 30 22 29

Dot gain is higher and the tone gradation more flat with FM screening compared to AM screening.

page 5

UCR or GCR, examples

UPM Finesse papers can "tolerate" heavy inking in printing, but the best of papers can be achieved with pre press operations utilising Under Colour Removal (UCR) or Grey Component Replacement (GCR). UCR must be used, if there appear problems of heavy black areas printed with all primary colours in the form of poor ink trapping, smearing or even ink areas peeling off. With high ink coverage the blistering and fluting problems are more easily occurring as well.

Many advertisers and printers working with WFC papers recommend the Total Ink Coverage (TIC) to be 280% at the maximum or some recommend even less, and all recommend definitely TIC to be below 300%, even if the recommendations for UPM Finesse are still over that (from 300-320%).

Full UCR vs. Traditional colour separation

95

68

85

58

85

58

80

100

0

20

40

60

80

100

120

Traditional UCR

Do

t a

rea

% cyan

magenta

yellow

black

TIC = 285%TIC = 345%

+ 20

- 27

Fig. 4. Full Under Colour Removal, effect to the Total Ink Coverage (TIC), maintaining grey balance and print densities.

If colour separation in pre press is done with full UCR as in the example case presented in Figure 4, it is possible to reduce the Total Ink Coverage from 345% to 285% and still maintain the target densities and grey balance. The relation of CMY grey of 27% corresponding to the 20% grey with black is based on neutral grey combination C30%M25%Y25% = K20%. In mid tones this relation is C50%M40%Y40% = K35%.

UCR and GCR offer also cost savings for the printers in the form of lower material and energy costs, without talking about environmental benefits.

page 6

60% UCR vs. Traditional colour separation

95

7985

69

85

6980

92

0102030405060708090

100

Traditional UCR

Do

t a

rea

% cyan

magenta

yellow

black

TIC = 309%TIC = 345%

+ 12

- 16

Fig. 5. Under Colour Removal of 60%, effect to the Total Ink Coverage (TIC), maintaining grey balance and print densities.

If there is no peeling-off, smearing or ink trapping problems the printer is seldom using 100% UCR, but just to assure the grey balance and "safe" inking. Very typical maximum levels are from 60% to 70% UCR. With 60% UCR it is possible - again in the example presented in Figure 5 - to reduce Total Ink Coverage from 345% to 309%, still maintaining grey balance and target densities in printing.

Grey Component Replacement (GCR) is used to print CMY grey tones with black colour in all tone areas from light to dark (UCR is working only in dark areas). GCR is based on so called acromatic colour separation, where all grey tones are meant to be printed with black and only colour tones differing from grey with CMY combinations. GCR as an operation is based on optical densities for each colour, normally based on the possible minimum and maximum densities of black in printing. The GCR as an operation in pre press can be done for instance with the following procedure:

Dk = (1 - G) x Dk,min + G x Dk,max ,where

Dk = density of black, G = level of GCR (0.0-1.0), Dk,min = possible minimum black and Dk,max

= possible maximum black. Typically, the level of GCR is from 60% to 80%. Using GCR (this might happen sometimes using UCR, too) the printer might run into the situation that the deepness of dark tones is too low or wrong in colour ("deep blue black") - in this case Under Colour Addition (UCA) is used to enhance the wanted dark tones.

page 7

Effect of Full GCR to Dot Area of primary colours

74 %

0 %

94 %

70 %

100 %

86 %

0 %

91 %

0 %

20 %

40 %

60 %

80 %

100 %

120 %

area, start area with GCR

do

t a

rea

% cyan

magenta

yellow

black

TIC = 268% TIC = 248%

Fig. 6. Effect of full (all of the weakest colour in CMY grey combination replaced by black) Grey Component Replacement to Total Ink Coverage.

GCR is not as effective tool to decrease TIC as UCR, but it has the benefit of more pure colour tones when avoiding so called secondary and impure reflections of the overlapping CMY grey tones. GCR is calculated normally according to the densities and based often to the tone gradation where equal densities of cyan, magenta and yellow form neutral grey in printing. In Fig. 7. there is an example of the changes in optical densities of cyan, magenta, yellow and black with full GCR similar as presented in Fig. 6.

Full GCR, effect based on densities

0,55

0,00

1,05

0,50

1,30

0,75

0,00

0,97

0,00

0,20

0,40

0,60

0,80

1,00

1,20

1,40

ODr ODr with GCR

Op

tic

al

De

ns

ity

Cyan

Magenta

Yellow

Black

Fig. 7. Effect of full GCR (Optical Density of 0.55 dimished from cyan, magenta and yellow - replaced with OD of 0.97 in black) to the print densities.

page 8

Print densities and ink demand

The grey balance, dot gain (print contrast) and colour formation determine the proper print densities for each paper. For UPM Finesse papers the recommended print densities are (ANSI, with polarising filter):

Table 2. Target print densities for UPM Finesse papers from Kymi mill.

Paper grade Cyan (C)

Magenta (M)

Yellow (Y)

Black/Key (K)

UPM Finesse gloss 1.65 1.60 1.45 1.90UPM Finesse premium silk 1.60 1.55 1.35 1.80UPM Finesse matt 1.50 1.45 1.30 1.70

The ink demand (ink mileage in printed copies) of UPM Finesse papers have been measured in different test printings done in labs and in pilot plants. The average ink demand values for UPM Finesse papers according to the tests are:

Paper Grade Ink demand in a constant density UPM Finesse gloss 1.10 g/m², D1.7UPM Finesse premium silk 1.20 g/m², D1.7UPM Finesse matt 1.35 g/m², D1.7

Ink demand of UPM Finesse papers

0,5

0,7

0,9

1,1

1,3

1,5

1,7

1,9

0,7 0,9 1,1 1,3 1,5 1,7 1,9 2,1 2,3

Print density (black)

Ink

dem

and

g/m

²

UPM Finesse gloss

UPM Finesse premium silk

UPM Finesse matt1,09

1,20

1,35

Fig. 8. Ink Mileage (Ink Demand) of UPM Finesse papers from Kymi, black ink.

page 9

3 Drying of UPM Finesse in HSWO

The drying in HSWO printing is effected by the following factors of papers and drying process:

moisture content of paper ink coverage in printing internal bonding strength of paper against blistering drying profile = weighing of drying between different chambers limitations in a dryer (length vs. printing speed, afterburner operation, control of

chambers)

The recommended web temperature in drying is 135°C in exit or in camera (in drying zone) and the drying should happen in one (1) second. This should be possible if the Total Ink Coverage is 300% or less. If the drying temperatures can be controlled between different chambers, then the drying should happen mostly in the first chambers - typically the hot air temperatures in drying with three (3) chamber dryers could be: 1st chamber 260°C - 2nd chamber 190°C - 3rd chamber 160°C. UPM Finesse papers should be dried with front weighed profiles, but avoiding the higher web temperature than 135°C (in exit or in camera). The peak temperatures for UPM Finesse gloss and premium silk is 150°C and for UPM Finesse matt 155°C. Even if these peak temperatures are possible they might cause decrease in print quality, mainly in printed gloss, especially if they are not cooled properly.

Drying temperatures of HSWO dryer in different phases from front-heavy drying to even profile drying

targeting web temperature of 135 °C

100110120130140150160170180190200210220230240250260

1 2 3 4 5 6 7

Ho

t a

ir t

em

per

atu

re °

C

1.chamber

2.chamber

3.chamber

4.chamber

Fig. 9. Possible hot air temperatures in HSWO drying targeting Tweb of 135 °C and going from front weighted drying to even drying profiles in different drying chambers.

page 10

Even if UPM Finesse is not containing mechanical fibres, too high drying temperatures can cause the loss of print gloss - especially, if the chilling is not effective enough. The web temperature after chilling should be 23 °C or below in order to achieve a proper print gloss and avoid smearing. The chilling of printed web should also be done with the proper profiling of temperature decrease. If the chilling is done with four (4) chill rolls the typical profiling is used: 1. 40% - 2. 25% - 3. 20% - 4. 15% of needed cooling. The cooling of printed paper to the level of 23°C or lower should happen in the same time than drying, that is about in one second.

The cracking of paper at the fold is depending on the ink coverage, drying temperature, folded tensile strength of paper, and the moisture content of paper before folding. If paper is too dry (dried too heavily or not re-moistened properly after drying), the tensile strength in cross direction of paper web can be too low. It seems to be so, that even if the cracking is mainly a problem of papers with high basis weight, all coated papers loose strength if they are too dry (see Fig. 10).

Tensile strength at fold vs. web temperature

0,00

0,20

0,40

0,60

0,80

1,00

1,20

1,40

1,60

1,80

90 100 110 120 130 140 150 160

Temperature °C

Ten

sile

str

eng

th a

t fo

lded

pap

er

kN/m

80 g

90 g

100 g

115 g

Fig. 10. Folded tensile strength dependance about drying temperature in HSWO, 0.60 is a critical level.

If the drying could be done with 10°C lower web temperature it would increase the cracking tolerance of paper about 20%. It is important to work on proper ink and fount amounts. It is also critical how well paper is getting the moisture back after drying, in order to avoid cracking either in a folder or in finishing (stitching of pages). This can be assured by moistening showers in folder area, spraying moisture with glue to the main fold of web before former folder, by silicone application and by assuring that chilling rollers are cool enough to condensate humidity onto paper (requires that the conditions in printing are not too dry).

page 11

Moisture content vs. folded tensile strength of UPM Finesse

0,00

0,50

1,00

1,50

2,00

2,50

1,0 2,0 3,0 4,0 5,0

moisture content %

fold

ed

te

ns

ile

kN

/m

Fig. 11. Folded tensile strength is depending on the moisture content of paper, red line is a critical level.

Drying windows of UPM Finesse papers

100 100105 105 110 110 110 110

115

160150

145

160 155 150

165 165160

60

50

40

55

45

40

55 55

45

0

20

40

60

80

100

120

140

160

180

70-80 90-110 115-130 70-80 90-110 115-130 70-80 90-115 130-150

Paper grade and basis weight

We

b t

em

pe

ratu

re °

C

0

10

20

30

40

50

60

70

just dry, nonsmearing, justscuffing temperatureblisteringtemperature

Drying window

UPM Finesse gloss UPM Finesse premium silk UPM Finesse matt

Fig. 12. Drying windows as web temperatures for UPM Finesse papers.

The lowest temperature to be used in drying can also depend on the dryer type. If the afterburner is integrated, then to reach 100 °C as Tweb could be difficult. In general, the VOCs are not burned effectively if the drying temperature is too low. This limit seems to be quite often 100 °C as a web temperature.

page 12

4 Printing materials

Printing inks

In order to get the best out of UPM Finesse papers, there are recommended things connected to the printing inks and fountain solutions. The proper ink trapping can be achieved, if the tack sequence of inks is lowering, following the principle: "print on tackier" - especially, when printing CMY colour combinations. The tack difference between consecutive printing inks should be 5%-10%, and the colour sequence in printing C-M-Y-K or K-C-M-Y. When printing the blue colours (cyan + magenta), the trapping of magenta on cyan is essential. With UPM Finesse Gloss this can be achieved with the printing inks of "the same tack" with the help of fast ink setting, but with the silk and matt grades the lowering tack sequence is needed. Typical and "easy to remember" rule for the relative tack sequence of the printing inks in K-C-M-Y printing sequence is: 10 - 9 - 8 - 7 (though black, K, could be lower).

Typical tack sequence in HSWO inks

150,0

160,0

170,0

180,0

190,0

200,0

210,0

Black Cyan Magenta yellow

Fig. 13. Tack sequence of HSWO inks: "print on tackier"; Difference from 5% to 10% is

needed at least with CMY coloured inks and definately with cyan (C) and magenta (M).

The best print quality with UPM Finesse gloss can be achieved with medium fast setting inks - with too fast setting inks there is a loss of print gloss due to "too ready surface before drying" (UPM Finesse gloss is a fast setting paper) - and there might be piling and unevenness problems, too.

The emulsification properties of the printing inks are very important for the ink-water balance and the quality in printing. This has a role in wetting of printing plates properly, too - especially with CTP plates, which have been grained differently than the traditional photomechanical offset plates. The emulsification rate in a saturation (measured with distilled water) should not exceed 60% but should be over 35% in order to avoid toning and difficult start-up in printing. The printing inks should have also good fount releasing properties and

page 13

contain small enough amount of residual fount ("water"), when emulsion is broken by transferring ink-fount emulsion through former rollers onto the printing plate. The emulsification rate of the inks could be asked from an ink manufacturer, because it is quite difficult to measure in production conditions.

As said earlier, UPM Finesse papers, especially UPM Finesse gloss, are more hydrophobic than hydrophilic papers. If the printing ink is emulsifying more than 60% of fount in ink-water balance situation with hydrophobic papers this can lead to two types of problems: dot gain is (too) high and in the long run ink might start piling on the rubber blankets (piling on each printing unit not back-trapping).

Too low usage of fountain solution with UPM Finesse papers is not so big problem than too high usage. In the cases, where the printer might want to use lower densities or really low total ink amount then there is a risk for toning with the inks of low emulsification, especially with CTP plates. There is not enough fount / water to keep the printing plate "open".

Fountain solution

Fountain solution is a very important factor for the print quality and especially when printing on paper, which is normally quite "water friendly" material. The following properties in "fount" are effecting to its absorption, emulsifying and wetting properties:

Temperature (in a tray and former rollers) Surface tension, polarity Viscosity Acidity, pH Hardness Conductivity Solubility

The fountain solution, which is used in most of the HSWO printing presses in Europe are containing tap water + additives. The best solution would be achieved by using Reverse Osmosis (RE) cleaning system to make pure base water and put certain salts and additives to control the final properties of fountain solution. There are two kinds of fountain solutions used: alcohol based (with isopropyl alcohol) and non alcohol ("alcofree") based. In "alcofree" fountain solutions isopropyl alcohol is replaced by other additives, which are not in all cases more environmental friendly than IPA, but causing less VOCs in printing.

page 14

When printing on UPM Finesse papers the following properties of fountain solutions have at least proved to be working in most of the HSWO processes:

Temperature in a fountain tray 12-15 °C (target 12 °C) Acidity, pH 5.2 - 5.5 (target 5.3) Conductivity 500 - 3000 S/cm (target 1100 S/cm) Hardness 5 - 15 °dH (target 8 °dH) Alcohol content (if used) 8% - 10% (target 8%) Additive content 2.5% - 3.5% (target 3%), suppliers instructions should be obeyed still Max. 10% overfeeding in a start After a successful start, fount feeding max. 3% over toning limit (after setting of rollers) "Feeding as less as possible"

Printing blankets and plates

UPM Finesse papers are meant for high quality printing. All properties in rubber blankets promoting high quality are recommended: high smoothness, some compressibility but hard enough, neutral feeding, easy releasing.

Printing plates are chosen today on the terms of printing process, CTP, inking and quality. Papers do not normally set any demands for printing plates.

page 15

5 Conditioning and handling of paper

In order to avoid the quality problems connected to the physical anisotropy of paper, the paper reels to be printed should be handled and conditioned properly. The paper is made in the mill to be used in a certain conditions by the temperature and moisture. In these conditions the strength properties and mechanical behaviour of paper can be predicted. The conditioning time of paper which is required before printing is depending on the temperature difference of paper and the print hall and on the diameter of the paper reel. How the paper is moistening or drying in a print hall is depending somewhat on the moisture difference of paper reel and print hall, but mainly on the hysteresis (relation of absolute moisture content in a paper against relative humidity conditions) behaviour and history of paper.

Hysteresis of paper in 22°C

0,0

5,0

10,0

15,0

20,0

25,0

30,0

35,0

0 10 20 30 40 50 60 70 80 90 100

RH%

AH

% w etting

dry ing

Fig. 14. Hysteresis behaviour of paper: different behaviour with the same absolute moisture content (different elongation etc.)

The best situation for the paper would be "standard conditions" with controlled conditioning, which is of course not possible taking into consideration the different seasons and global differences in printing conditions. Anyway, in order to avoid the biggest problems due to different conditions inside the wrapped paper reel compared to the print hall, the following conditioning times presented in Fig. 15 connected to the temperature differences should be used.

page 16

Conditioning times of paper

0

20

40

60

80

100

120

3 6 9 12 15 18 21 25 30

temperature difference °C

ho

urs

0,2 m³ / Ø 250 mm

0,5 m³/ Ø 400 mm

1 m³ / Ø 550 mm

2 m³ / Ø 800 mm

3 m³ / Ø 1000 mm

4 m³ / Ø 1125 mm

5 m³ / Ø 1250 mm

Fig. 15. Conditioning times of paper (reels = diameter, pallet = volume); Temperature differences typically between the red lines.

The conditioning of the paper reels should happen the edge covers off but other wrappings still on in the same conditions as in a printing machine.

Example. If 125 cm diameter reel is in a warehouse with the temperature of 14 °C and to be printed in a print hall where the temperature is 22 °C, then the required conditioning time is approximately 24 hours.

page 17

6 Web tension in printing

UPM sheet 21

UPM HSWO PapersTensile strength vs basis weight

1,5

2,5

3,5

4,5

5,5

6,5

30 36 42 48 54 60 66 72 78 84 90 96 102 108 114 120 126 132

Grammage g/m²

Ten

sile

str

eng

th m

d k

N/m

TD

NEWS/INP

SC

MFC

LWC

MWC

WFC

Maximum peak tension in printing could be = Tensile strength md / 6

Fig. 16. Tensile strength in machine direction of UPM papers.

The maximum recommended tension in printing could be one sixth of tensile strength of paper in machine direction. With UPM Finesse 90 gsm paper this means the peak web tension about 750 N/m. This tension should be enough for all UPM Finesse papers in HSWO printing, even if recommended for 90 gsm grade.

page 18

7 Directive recommendations for UPM Finesse matt

UPM sheet 19

UPM Finesse matt from Kymi millpaper category: WFC

Coated woodfree -perfect image print out- paper for HSWO printing

Coated fine paper, machine- and softcalendered, matt Furnish: chemical pulp, fillers, sizing Available in basis weights of 80 – 130 g/m² Brightness 97%, Opacity range 93 – 98%

To be noted in printing, recommendations

Screen ruling 60 – 80 lpcm (70 lpcm) Best result with high snap HSWO inks, high rub resistance

in the inks recommended Ink demand 1.3 – 1.4 g/m² for print density of D1.7 Black UCR or GCR recommended, maximum TAC 300%-310% Directive target print densities, ISO Status E / DIN + pol.:

C1.50-M1.45-Y1.30-B1.70 Average dot gain in 50% halftone of black: 16-18% Peak web temperature in drying < 155°C,

but lowest possible temperature recommended

Fig. 17. Directive recommendations for HSWO printing of UPM Finesse matt.

page 19

8 Directive recommendations for UPM Finesse gloss and UPM Finesse premium silk

UPM sheet 20

UPM Finesse gloss, UPM Finesse premium silkpaper category: WFC

Coated woodfree -finest art on top- paper for HSWO printing

Coated fine paper, super- and softcalendered, gloss and silk

Furnished by chemical pulp, fillers, sizing Available in basis weights of 70 – 250 g/m² Brightness range 98 - 100%, Opacity range 91 – 100%

To be noted in printing, recommendations

Screen ruling 60 – 80 lpcm (70 lpcm) Best result with high snap HSWO inks

Ink demand 1.1 g/m² for print density of D1.7 Black UCR or GCR recommended, maximum TAC 320-330% Directive target print densities, ISO Status E / DIN + pol.:

Silk: C1.60-M1.55-Y1.35-B1.80Gloss: C1.65-M1.60-Y1.45-B1.90

Average dot gain in 50% halftone of black: 14-16% Peak web temperature in drying < 150°C,

but lowest possible temperature recommended

gloss

premium silk

Fig. 18. Directive recommendations for HSWO printing of UPM Finesse gloss and premium silk.

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9 Summary, directive recommendations for UPM Finesse WFC papers

UPM sheet 23

Summary of basic print recommendations forUPM HSWO papers

160 °C

160 °C

155 °C

750 N/m

750 N/m

750 N/m

ISO 12647-2 PT2

ISO 12647-2 PT2

ISO 12647-2 PT2

ISOcoated

ISOcoated

ISOcoated

300%

310%

310%

54-70 lpcm (60)

54-70 lpcm (60)

60-80 lpcm (70)

UPM Finessematt

UPM Finessebulky matt

UPM Finessepremium silk

WFC matt

150 °C750 N/mISO 12647-2 PT1ISOcoated320%60-80 lpcm (70)UPM Finessegloss

WFC gloss

160 °C

160 °C

700 N/m

700 N/m

ISO 12647-2 PT4

ISO 12647-2 PT4

ISOuncoated

ISOuncoated290%

300%

54-70 lpcm (60)

54-70 lpcm (60)

UPM Fine

UPM Fine SC

WFU matt

silk

150 °C650 N/mISO 12647-2 PT1ISOcoated320%60-80 lpcm (70)UPM Star HMWC gloss

155 °C650 N/mISO 12647-2 PT2ISOcoated290%54-70 lpcm (60)UPM Star M HMWC matt

Peak

web temp.

Peak (directive)

web tension

RecommendedISO print standard

Recommended

ISO-ICC profile

Recomm.

TAC%

Recommendedscreen ruling

Paper

brand

Papercategory

Notice: TAC%, paper grades and standards do not fully match

Fig. 19. Directive general recommendations for HSWO printing of UPM Finesse papers.

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