Suppliers of the finest quality Photo Resist and Sand Blasting Equipment

10/254 Milperra Road, Milperra NSW Australia 2214

Phone: (61) 02 9772 1999   Fax: (61) 02 9792 2374 

Email: sales@problast.com.au

 

PROCEDURE DOCUMENT

 

 

QUICK SANDBLASTING  PHOTOS

USING COREL DRAW 9 or 12

 

These notes will take you through a quick process of preparing a photograph for sandblasting within Corel Draw. It’s assumed the photo to be used is perfect for the job at hand and does not require any further editing (e.g. removing of backgrounds). This procedure has been tested with Corel Draw 9 and 12, however the concepts covered in these notes may apply to other versions as well. These notes are intended as a guide only and will require your own experimentation to get the effect you need.

 

 

LETS GO…

Once you’ve laid out your artwork page in Corel Draw, including placement and sizing of your photo, the next step is to convert your photo to grayscale.

 

Select your photo with the Pick Tool, then from the top menu bar select:

Bitmaps > Convert to Bitmap

 

 

 

 

Set your Colour selection to Grayscale (8-bit) and your resolution to 150 dpi and pres OK.

 

 

Now sit back now and take a good look at your photo, are all the features clearly defined?

 

 

If you need, you can sometimes enhance the photo slightly by adjusting it’s brightness and contrast. You can find this tool on the top menu bar under:

 

In Corel Draw 12:  Effects > Adjust > Brightness/Contrast/Intensity

In Corel Draw 9:                    Effects > Colour Adjustment > Brightness-Contrast-Intensity

 

 

 

CONVERT TO HALFTONE

The next step is to convert our photo to a halftone screen. This process will convert your photo to a series of fine dots just like the photos you see in a newspaper.

 

This is done with   Bitmaps > Mode > Black and White (1 Bit).

 

 

* If you are etching glass, set  the conversion type to Jarvis, leave the Intensity setting at 100.

 

* If you are etching stone or metal, you may need to create your artwork with a coarser dot pattern. Set the conversion type to Halftone, and the Screen Type to Round. The lines per inch setting will determine how fine the detail is in your image and will range from 20 to 40 lines/inch depending on the material you want to sandblast. The larger the lines per inch, the more detail the final image will contain, however it will also be harder to wash out the resist and sandblast! For  stone or metal set the lines per inch to 25 lines per inch, 30 degrees, if you want to try this filter on glass set the lines per inch to 35, 30 degrees. If interference patterns start to appear amongst the dots try changing the angle of the dots.

 

CREATE A NEGATIVE

There’s one more step to go, the artwork needs to be inverted to become a negative. The reason for this is that anything black in the artwork will become sandblasted area (white frosted on glass), so imagine someone in your original photo with black hair will end up sandblasted with white hair!

 

 

To convert the image to a negative , Effects > Transform > Invert.

 

There may be times when you don’t want to change your image to a negative, for instance you may wish to paint fill your etching with a dark colour.

PRINTING

It is crucial that you produce a good print for exposure. While Vellum will provide acceptable results for coarser images, the best results for high detailed work will always be achieved by using Laser Film or Inkjet Film.

 

EXPOSURE AND WASHOUT OF FILM

Your artwork consists of thousands of tiny dots and you must be careful not to over expose your resist. Overexposure can cause undercutting (i.e. light seeping in around and under the black), which can then result in difficuly in washing out the resist and a loss of image detail.

 

A proper washout technique is required to achieve a good resist. Washouts should be done as quickly and evenly as possible so as not to saturate the resist and wash away the tiny dots. Keep perpendicular to the resist with the water spray at about 15 centimetres away.

 

It’s not hard to washout photographic images, but you will need to practice the correct washout procedure.

 

DRYING THE RESIST

Drying is the same procedure as doing any other sand blasting job. Just be gentle with the blotting towel while the resist is still wet.

 

APPLYING THE ADHESIVE – SR2000 Resist

It is vital that you use a very thin layer of adhesive so that blasting produces the etched image fast. We recommend the spray on adhesive method of applying adhesive directly to the resist using either thinned down RZ-2 adhesive in our adhesive spray gun or using the spray can adhesive method. Either way a very light, even coating of adhesive is required.

 

Using the sponge brush method onto the product to be blasted may work but it is difficult to apply a very thin, even layer of adhesive this way and you most probably won’t get 100% success.

 

Apply the resist to the product to be blasted in the usual way.

 

ETCHING

We recommend an air pressure setting of 20-25psi when using a pressure pot system. Low pressure will reduce the risk of blowing off the tiny half tone dots.

 

Again you need to strictly follow sand blasting procedures holding the nozzle 15 centimetres away from the surface at a 90o angle. Not keeping your nozzle perpendicular to the surface can cause cutting under the resist dots.