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Screen Printing onto Clay
Place your own designs onto clay, repeatedly at a low cost, using a simple technique - with RISO ScreenMaster it's easy.
The screen used for this process is RISO ScreenMaster 70 Mesh. RISO ScreenMaster is a combination of screen and stencil [polyester screen and saran film], with a coated [shiny] and uncoated side.
The design is imaged onto the screen by using a NEHOC Screen printing or Ceramic Printing Kit, PRINT GOCCO PG-5/ PG-11/ PG Arts/ B6 or B5 model, RISO SP-275 ScreenFax, Vistafax Thermal Copier [or similar] in a flash!
Let's explain the process of placing a two colour design onto clay, starting from a single piece of artwork/drawing
Producing your artwork
To gain the two colour separation, the artwork must be colour separated. After drawing or copying a suitable design, fix the original piece of artwork onto a light box [or similar]. Overlay a new sheet and trace all areas to be printed in the first colour from the original - creating your new piece of artwork. Overlay an additional sheet and trace the second part of your design
You now have the two colour separation artwork.
Remember that you MUST completely colour in areas black that you wish to reproduce as a solid area - DO NOT leave as a line drawing [unless desired].
Lay the completed tracings on top of the original and check for areas which may have been overlooked.
Preparing the Artwork
It is preferable to use photocopies for the 'imaging artwork' rather than carbon pen, because the original tracings can be kept for future use.
When access to a photocopier that will enlarge/ reduce the design is available, a single set of artwork can be used to reproduce a range of sizes i.e. dinner & bread plates.
Place the design onto the photocopier stage and copy at the lightest setting available before the design begins to lose quality. Even the lightest setting is enough carbon to image a screen - too much carbon can block the screen and create problems with very fine designs or solid areas. [see Artwork Clean-Up Information Sheet to cure such problems]. A light setting will also help eliminate 'spotting' that naturally occurs in some photocopiers due to age/ general use
After you have copied your design, check for 'spotting' or other unwanted marks. NB: If you touch up the design with correction fluid/ pen/ etc - YOU MUST MAKE A NEW COPY.
If the marks can be cut out by knife or scissors than do so - you will not need to make a new original.
NB: Ensure cuts are no closer than 2mm to edge of design.
Using your photocopied designs, image against the coated [shiny] side of the mesh on a PRINT GOCCO or previously mentioned thermal copier as per the models instructions
Repeat the process for the second part of the design
Place the plastic frame mounts on a flat surface, tape upwards, and remove cover from tape
Mount the imaged screens onto the plastic frame mounts as per standard procedure - Instructions for this are readily available. Ensure that the screen has no ripples but is not too tight/ buckled [the frame will bend] as over tightening may distort your image
Remove your artwork and your screen is ready for use
Combining any fabric printing reduce [water based] as a medium and powdered underglaze colours, make a fairly thick paste - peanut butter consistency
For stoneware, inks can be made using oxides for colourants and the same printing paste
Pre-mixed colourants may also be used for the printing process
Preparing to print
When the slab is prepared, have ready . . .
Brushes - one for each colour, fairly stiff bristle
Pigments - ready mixed
Screens stacked in order of use
Positioning the design
It is helpful to have the area for the placement of the design on the clay marked in some fashion,a light scratch with a pin just outside the desired area, sufficient to be seen THROUGH the screen, is one method.
NB: As soon as the first colour is laid down the scratch can be lightly smoothed over.
Printing the first
Dry the area to be printed with a hair dryer and place the screen down immediately
Using a brush, apply sufficient colour to cover the design area - no need to waste ink on unused areas of the screen! Make sure no part of the design is missed - it is best to check by holding one side of the frame and gently lifting the other side [in a hinge action], checking as you lift.
If there is one, lower the screen immediately and brush the area - repeat as necessary.
After lifting the first screen, dry the area with a hair dryer ready for the next colour
Registration of the second screen is done by looking through the screen while gently lowering it into position
For additional screens/ colours, repeat this registration process as required.
It is important however to adjust the size of the ScreenMaster to fit within the clay shape. This will prevent it from curling over and marking the clay surface.