Grafica News - November 2007

CAZA'S WORKSHOPS IN INDIA
My first ever programmes at DMI



Michel Caza, an international expert, visited India's only one and a brand new institute for screen printing technology Dhirubhai Mistry Institute for Print Education, Research & Training near Mumbai few months ago. DMI was set up by Grafica Flextronica, a leading manufacturer of screen printing machines and other equipments. The purpose of his visit was to conduct two 3-day workshops which was well attended by over 60 people each.

Says Caza in his own words, "the purpose of my visit between December 4th and 9th was to manage on behalf of FESPA two three days long workshop. Here we go..."

WORKSHOP 1: 'Four Color Halftone Fine Line Screen Printing (150 LPI)'

December 4-6, 2006

  • How to achieve 150 LPI screen ruling by screen printing process and maintain color consistency as per original
  • What are the prepress parameters and screen making system
  • How to maintain consistency on press while printing (color sequence, press parameters, etc...)

For this session, accuracy, precision, high technology control, scientific approach of technical problems are the key words.

31 attendants (a little too much when we come in practical workshop) work : everybody must be able to see in detail each operation, and in the screen making room, it was a little «tight».

The diversity of applications used by the attendants w as extremely interesting : graphic decals, glass, textile, packaging containers, toys printing, etc.) and I tried to find solutions to each of the problems posed by those so different applications. Alternately, during three full days, theory and, mostly , practice in the workshop part, a clean room we entered with shoes-cover , white apron and cap in this “clean room” ! - More than unusual in a School !

Day one :
Morning,(2 H 30 ) using the Conference room facilities, explanations about the necessity to reduce the number of parameters (120 of which 90 are 'variables'). How to 'simplify' the whole job and to control every detail in principle - prepress, films, dots, fabric, frame, tension, emulsion, coating, substrates, inks, squeegee and flood bar, other printing parameters, printing sequences, UV curing parameters, etc.

Afternoon (4H) in the School of Printing (next door to Conference hall) and with the 'demonstrative help' of the students we could work on screen tension (23-25 N/cm), gluing, preparing the fabric, coating (emulsion coating), ghost images reclaiming, squeegee sharpening, UV ink preparation:

Day two :
This day was dedicated to prepress work and Color management - Morning, how to establish ICC profile in the 'Caza's way, cheap - and how to work on an image to make it a good 'selling tool' for the customer , demonstration of Photoshop work on an image.(3H). Afternoon a long session about the use of the Profile Maker 5.0 of Greta Macbeth an other expensive, unfortunately - manner to build « automatically » a compensated ICC profiles related to screen printing (4 H)

Day three :
Morning - A mix of practical and theoretical sessions. Printing made by the students with attendants present: following different sequences : CM and MC, 150 lines/inch. In between prints, screen setting and so on, some theoretical session in the conference room about ink thixotropy, prepress workflow (TIF, EPS, data transfer, embedded files, etc...(3H)

Afternoon - End of printing : YK and KY on the CM and MC printed in the morning to show if my sequence MCKY ('Cazaway process') was the best. The demonstration was evident and, according to the chosen image this MCKY (magenta, cyan, black, yellow) gave the best result.

Demonstration of visual moiré research, exposure and washing of the screens. After this a theoretical session about moiré problems and solutions, study of compensation density curves (3H). Then 1 hour was dedicated to the feedback and analysis (very positive) of the three days workshop by the attendants.

TECHNICAL PARAMETERS According to the principle of « reduction of the parameters », we had the following technical elements to take care of :

  • Correction of the curves (ICC profile) made with the Profile Maker 5.0 Gretag Macbeth
  • Films made on Agfa image setter in 150 lines/in (elliptical dots 2).
  • Screen fabric 180/27 Sefar yellow stretched at 23 N/cm
  • Emulsion, one single coat substrate side (thin edge for the coater tray on the fully automatic coating machine GF- 3040 EC of Grafica with Dirasol 902 dual cure Sericol.
  • Exposure : 125 impulsions of light (+ or one impulsion/second) on Grafica's GF-3040 EXCB/A angular contact box.
  • Mat coated paper 250gr - 56 x 71 cm (22 x 28 inches)
  • Ink, UV mat 8 MK from Encres Dubuit
  • Squeegee blade : Serilor 90-65- 90 shore from Fimor - printing angle 75°.
  • Printing on semi-automatic Grafica clamshell press GF-3040 (30 x 40 inches), with 2 mm off contact.
  • Squeegee speed 20 M / minute
  • Speed of flood bar (of 500 μ thickness) : 10 M / minute

UV Curing on a Jet Air Dryer Combo (multiple drying) unit Grafica (Air pulsed, UV , cooling) here UV was used at 120 W/cm, one lamp and at a speed of 45 M/minute.

WORKSHOP 2 - Art screen printing using stochastic grains

December 7-9, 2006

11 attendants, an excellent number for practical work, especially on something as movable and sometimes « bizarre » as Fine art printing.

  • Selection of right stochastic grain
  • What should be the right densities for printing
  • What are the prepress parameter and screen making system
  • How to maintain consistency on press while printing and achieve the color work, «adaptation» or «reproduction» of an piece of art

For this session, very different motivation : we are in full art and if a certain a lot as matter of fact amount of technology is quite necessary, the notion of « art » with all the spirit of freedom in creative expression that it means and that will be one of the « messages » to transmit to attendants.

The technical data were identical to the ones seen above for the first workshop at the exception of the paper, here a 25% rag art paper of 50 x 70 cm, 350 gr, and, of course, the wished variations in the exposure times of the different screens.

It started with a long conference to explain and show the history of art screen printing, its specificity if compared with industrial screen printing, its deontology, the huge difference between an « original serigraphy », an « art reproduction », an « art poster ». The old technologies from the beginning of our century , the movement in direction of the use of modern analogue photographic first, then digital, to create or reproduce (to very different things) images from the contemporary or/and older artistical expressions.

All those notions like it is the case in China as I could realize in my long Ningbo Conference are not yet familiar for the Indian screen printers.

I also explained the « sequence of printing », the principle of digital stochastic films as a successor of my « continuous tone technology (1963) first, then grained contact screens, analogue scanner random system and finally stochastic imaging through image setter from the digital principle and algorithms.

The principle of the « addition » of transparent colors to build up the image in successive printing that can go from 7 to 18 according to the wished and... financial possibilities of the artists or editors.

The 4 films used were made using a Gevaert Image setter with a 14μ grain size Crystal Raster. (it seems impossible, as most screen printers printing stochastic start at 65μ grain). But my technology allows it.

I also had to explain how, working with only 4 stochastic films (CMYK), we will make different screens :

  • First : 1 cyan, + 1 magenta, + 1 yellow for the light tone with an exposure of 15 impulsions of light
  • Then 1 magenta, + 1 yellow and + 1 cyan for the mid and dark tones with an exposure of 100 impulse,
  • And finally one black (100 impulsions) and a very dark magenta (500 impulsions). = 8 printed colors with 4 films, only playing with the exposure times of the screens.

We prepared the screens and show all details of it like in the first workshop (tension, preparing, coating, exposing, developing, etc.

This image was my « personal interpretation » of the abstract creation of an Indian painter : I widely explained that an « original serigraphy » was a recreation, not a « reproduction ». Also that a serigraphy must be, by definition, hand signed by the artist (then of course alive), printed in a limited and numbered edition and never reprinted !

Day one
Morning (3H), a long conference to explain and show the history of art screen printing, its specificity if compared with industrial screen printing, its deontology , the huge difference between an 'original serigr aphy', an ' art reproduction', an 'art poster'. The old technologies from the beginning of our century , the mov ement in direction of the use of modern analog photogr aphic first, then digital, to create or reproduce (to very different things) images from the contempor ary or/and older artistical expressions. All those notions like it is the ca se in China as I could realize in m y long Ningbo Conference are not y et familiar for the Indian screen printers.

Afternoon, I explained the 'sequence of printing', the principle of digital stochastic films as a successor of my 'continuous tone technology (1963) first, then grained contact screens, analog scanner random system and finally stochastic imaging through image setter from the digital principle and algorithms. The principle of the 'addition' of transparent colors to build up the image in successive printing that can go from 7 to 18 according to the wished and... financial possibilities of the artists or editors.

The 4 films used were made using a Gevaert Image setter with a 14μ grain size Crystal Raster. (it seems impossible, as most screen printers printing stochastic start at 65μ grain)... But my technology allows it.

I also had to explain how , working with only 4 stochastic films (CMYK), we will make different screens :

  • First : 1 cyan, + 1 magenta, + 1 yellow for the light tone with an exposure of 15 impulsions of light
  • Then 1 magenta, + 1 y ellow and + 1 cyan for the mid and dark tones with an exposure of 100 impulse,
  • And finally one black (100 impulsions) and a very dark magenta (500 impulsions). = 8 printed colors with 4 films, only playing with the exposure times of the screens.

We prepared the screens and show all details of it like in the first workshop (tension, preparing, coating, exposing, developing, etc.

Day two
Morning, we started printing the three first colors (high lights) with the same 8 MK ink but with densities around 0.50 with some slight modifications to give a balanced grey.

At the same time, we were preparing the second set of screens (mid/dark tones) and, as we shall do during the two remaining days, make in alternately some seminar sessions about for example the use of Photoshop and Illustrator or Corel Draw as a creation tool for artists or screen printers working for and with artists.

We show how to adjust the ink densities using transparent base and I tried to explain the 'pure feeling' that will give you the notion of the densities to print, the exposure time of the different screens, the pressure to apply while printing, the relativity and personalization of the judgment of the eye with each person. A gap and big difference with the scientific approach in process printing and 'artistical expression'....Not so easy to explain !

In the afternoon, the 3 mid/dark tones printing also showing and explaining how different can be an image made with 14μ films more or less exposed when screening.

Same thing with the densities that jumped from 0.50 to 1.00.

Making of the two last screens (black and very dark magenta) and showing how you can also play with the pressure of the water jet to literally 'paint' on the screen to increase the density in some place for example. We had also to add a slight correction in a part of the light magenta that was too 'feeble' because of an insufficient partial washing of the screen

Day three
In the morning we printed the two last colors black at O .70 (no 'pure black but only shadows in the image') and the last touch with a screen-printing. Again, don't forget that the gr aphic applications are only a quart of the screen-printing applications.

Let us be realistic : digital printing took some parts of the market and will take more of small screen printing companies, but when the companies using it are basically screen printers (and in the world they control 50% of the wide format digital printing), y ou simply use an other technology to open a new mark et that was not possible be fore, mostly for cost reasons.

T o end, I like to repeat my ' credo' : we are not anymore 'printe rs', screen, digital, or ev en offset or flexo ... W e are 'image mak ers and services providers' and we must know a lot about man y things : this is our future and to find it we need to imagine and create it : it does not 'pre-exist', it is in our hands, br ain and dreams.

As an expert what are your feedback/suggestion to Indian screen printers?
My answer is partly self -contained abov e ! But I should add that you will ha ve to work in differe nt directions : some 'niche' applications can be extremely profitable, both for small and for big companies. F or some others, they will hav e to produce fast, relativ ely cheap , in big quantities : this will need inv estments, a certain size and financial aptitudes. F or some other , the marke t will be at the local scale... But in all the cases, it will be very competitiv e and hard : don't forget that, unfortunately , there is alwa ys someone to produce « bad and cheap » and some customers to buy it... Ev en if it is for a short moment and gener ally ends with a commercial catastrophe both for the printer and his customer !

But, believe me a gain, your future goe s through Quality and the digital images I sa w in Mumbai at the moment of the elections are so poor and so bad that I should never v ote for the poor people shown on the banners ! So , don't do it !

T ry to control your work if you ha ve the equipment and desire for it - from the v ery beginning (creation), to the very end (shipping). The more control you will hav e, the easiest it will be for the customer who speak only to 'one single person', and for y ou because you can choose your products and act as well in mark eting as in production for your customer: think 'global' and you will also mak e more money!

This is a modal.

Reveal makes these very easy to summon and dismiss. The close button is simple an anchor with a unicode character icon and a class of close-reveal-modal. Clicking anywhere outside the modal will also dismiss it.

×