Skip to content
Discebo.dk

§ 19

Screen printing: colour consumption from weave

How many litres of paint should I mix for the run?

Answer: In screen printing, the mesh determines how much ink is laid down. The mesh supplier specifies the mesh's theoretical ink volume Vth in cm³/m² (open area × thread thickness), and 1 cm³/m² equals a wet layer of 1 µm. According to SEFAR's handbook for screen printers, the theoretical coverage is 1000 ÷ Vth square metres per litre, corrected by a factor S for the substrate's absorbency (0.5-1.0) and a factor V for dilution (1.0-1.2). The calculator converts the printed area in the run to litres of ink.

Formula

Teoretisk farvevolumen Vth (cm³/m²) = åbent areal (%) × vævets tykkelse (µm) ÷ 100 (står i vævets datablad)

Dækningsevne (m²/l) = 1000 ÷ Vth × S × V (SEFAR: S = 0,5-1,0 for sugende underlag, V = 1,0-1,2 for fortynding)

Trykt areal = motivets areal × farveandel × antal tryk

Farveforbrug (l) = trykt areal ÷ dækningsevne

Symbols and units in the formula
SymbolMeaningUnit
vthTissue's theoretical colour volume (Vth from data sheet)cm³/m²
trykt_arealMotif area per piece (width × height)cm²
daekningShare of the subject that is colour%
antalNumber of prints (items)stk
s_faktorCorrection for substrate absorbency (S)
v_faktorCorrection for dilution (V)
=Paint consumptionl
=Paint consumption in mlml
=Coveragem²/l
=Total printed aream²

Validity and source

Source
SEFAR Handbook for Screen Printers: m²/l = 1000 ÷ Vth × S × V

Does not apply when

  • Theoretical consumption for one print with one colour. Spillage in the frame, in the colour cup and at startup is additional, and a textile print with two strokes (print-flash-print) counts as two prints. Always use Vth from the datasheet for the exact fabric the frame is stretched with.

Worked example

The calculator's own default values inserted. The figures are calculated with exactly the formula the tool uses.

Substituted

  • Tissue's theoretical colour volume (Vth from data sheet)18 cm³/m²
  • Motif area per piece (width × height)600 cm²
  • Share of the subject that is colour60 %
  • Number of prints (items)500 stk
  • Correction for substrate absorbency (S)0.80
  • Correction for dilution (V)1

Giver

  • Paint consumption0.40 l
  • Paint consumption in ml405 ml
  • Coverage44.4 m²/l
  • Total printed area18.0 m²

Members only

The calculator itself is locked

Create a free user account to unlock all articles, calculators, templates and range — and get access to quizzes and classes. It takes less than a minute: name, email and a password. No payment card.

Create free user →Log in

Want to try something first? See what you can use without an account — the junior zone, the encyclopedia, the videos and more.

Sådan bruger du den

Før et serigrafijob på T-shirts, skilte eller plast skal du blande farve nok til hele oplaget, men ikke så meget, at resten skal kasseres. Vævets farvevolumen styrer, hvor meget farve der lægges på. Beregneren bruger SEFARs formel til at regne fra væv og motiv til liter.

Step by step

  1. Find vævets teoretiske farvevolumen Vth i databladet, fx 18 cm³/m².
  2. Mål motivets bredde × højde og vurdér, hvor stor en del der faktisk er farve.
  3. Vælg S efter underlaget: tæt til 1,0 for plast og bestrøget materiale, ned mod 0,5 for sugende tekstil. V er 1,0 for ufortyndet farve.
  4. Beregneren regner dækningsevnen i m²/l og deler det trykte areal med den.

Typical errors

  • At bruge Vth fra et andet væv end det, rammen er spændt med.
  • At regne hele motivets firkant som farve. Brug den andel, der faktisk dækkes.
  • At glemme farven i rammen og i koppen. Bland lidt ekstra oven i resultatet.

Examples from everyday life

Logo på 500 T-shirts

En håndboldklub bestiller 500 T-shirts med et brystlogo på 20 × 30 cm, hvor ca. 60 % er farve. Vævet er et 120-34 med Vth 18 cm³/m², og bomuld suger, så du sætter S til 0,8.

Tissue's theoretical colour volume (Vth from data sheet)
18 cm³/m²
Motif area per piece (width × height)
600 cm²
Share of the subject that is colour
60 %
Number of prints (items)
500 pcs
Correction for substrate absorbency (S)
0.8
Correction for dilution (V)
1

It means: Du skal bruge ca. 0.4 l farve, altså 405 ml. Dækningsevnen er 44.4 m²/l, og det trykte areal er 18 m².

Skilte i plast

En vognmand skal have 200 skilte i PVC med tekst på 40 × 25 cm, hvor 25 % er farve. Vævet har Vth 12 cm³/m², og plast suger ikke (S = 1,0).

Tissue's theoretical colour volume (Vth from data sheet)
12 cm³/m²
Motif area per piece (width × height)
1,000 cm²
Share of the subject that is colour
25 %
Number of prints (items)
200 pcs
Correction for substrate absorbency (S)
1
Correction for dilution (V)
1

It means: Jobbet bruger kun 60 ml farve. Dækningsevnen er 83.3 m²/l, så bland en lille portion og hold resten til næste job.

Hvid underfarve på mørke trøjer

200 sorte hættetrøjer skal have et motiv på 30 × 35 cm, som er 70 % farve, med hvid underfarve gennem et groft væv med Vth 35 cm³/m². Trøjerne suger meget (S = 0,6).

Tissue's theoretical colour volume (Vth from data sheet)
35 cm³/m²
Motif area per piece (width × height)
1,050 cm²
Share of the subject that is colour
70 %
Number of prints (items)
200 pcs
Correction for substrate absorbency (S)
0.6
Correction for dilution (V)
1

It means: Underfarven alene kræver ca. 0.86 l, fordi det grove væv og det sugende stof giver en dækningsevne på kun 17.1 m²/l.

Rule of thumb

Med Vth 20 dækker 1 liter teoretisk 50 m² på et underlag, der ikke suger.

How to check the answer

Trykt areal ÷ dækningsevne skal give forbruget i liter.