What is a blue print /Cyanotype fabric?
It is a pretreated fabric that allows you to make white prints on a blue background. The blueprinting is one of the permanent fabric printing techniques.
When you buy the blue print fabric, it will be of a pale green colour but once it is exposed to the sun and it is washed it turns to a blue colour, leaving the print in white. The fabric is also called Cyanotype Fabrics. You can ask for Cyanotype pretreated fabric.
The blue print fabric is available in many sizes ; you can even get it in A4 size sheets . It is made of cotton or silk noil and it is treated with some powerful chemicals like Potassium Ferricyanide. You will get it sealed in a bag ( a UV protected bag/ black plastic bag) and it is not exposed to any light till the last minute after everything is ready for the printing.  Other than the blue and white combination you will also find Green with Light Green prints, Green with Orange prints , Blue with Pink prints, Blue with Turquoise prints with the same functionality – it sure is a fun way to do fabric printing
Related post : Check out the post on the different methods of fabric printing techniques
How is the printing on blueprint fabric done
This simple printing process is also called sun printing and the basic process was invented by Sir John Herschel. He is a British inventor who has done amazing work in the field of colour photography. You can read more about him here .
Vivid permanent prints of different objects like feathers, flowers, photographs, anything that you want can be recreated on this specially formulated fabric – the best thing is you can do it yourself at home with the blue print /Cyanotype fabric and some ingenuity and donkey work. Just joking about the hard work – it is one of the simplest ways of printing on fabric.
What can you print on the fabric
Anything that is flat . You can use printed drawings and texts, large photographic negatives, everyday objects which will lie flat on the fabric , lace and other open weave fabrics, computer printed designs ( printed on acetate sheet), stencils
You can print your photos as a negative on this fabric – if you have a photo and you want to transfer this into the fabric with this printing process it is very easy to do – just print it in a clear transparency /acrylic sheet. Use it the same as any other object and you will get a photo negative effect on your blue fabric.
Imagine printing out photos of each of your family members on the blueprint fabric and using it to make cushion covers – no more fighting over whose pillow it is when watching tv.
Blue printing Process
The blue printing process is quite simple – The object is kept close to the blueprint fabric and exposed to sun light, resulting in the beautiful image imprinting on it as a negative printing – the print will be white while the background changes to blue. Different exposures result in different shades in the print.
Choose a very sunny day for your sun printing. If the fabric is wrinkled press on the wrong side of the fabric with a dry iron
Keep the fabric flat on a flat surface ; better to tape it on to a cardboard or something stiff /flat like a styrofoam sheet.
Keep acetate sheet or real object like a leaf to be printed on the fabric .
Keep a piece of plain glass or clear acrylic ( which will not block sunlight at all- total transparency is needed here) on top of the object to make it flat and increase tight fit to the fabric. The glass should make the printing object as close as possible to the fabric. Keep this exposed to the sun for some 10 minutes – more if the sun is not warm enough
Overexposure and under exposure to the sunlight are both not good for this printing – with overexposure you will find the print is not visible – the whole thing will be dark blue. If under exposed, i.e if you took it out too early, the print will be a light green shade; not the white you wanted it to be.
Take out the object carefully from the fabric. If everything is as you wanted , rinse the fabric in clear cold water, before using. Use a little bit of Hydrogen Peroxide in the first rinse to deepen the blue colour of the fabric.
Important tips in using the Blueprint fabric
Do not expose the fabric to any light before the printing process. If you want to cut up this fabric it will be better to do it in a room with little to no sunlight /any light.
One thing you have to be careful when dealing with the blue print fabric is that your hands and any object touching the fabric should be dry
You should also be using gloves when handling the fabric before it is washed as it may contain harmful/allergic chemicals. You should also preferably use a mask; if you are the allergic kind, these precautions are absolutely necessary.
Do all the preparations before printing inside the house
The fabric is coated with the chemicals only on one side and you will have to check this before printing.
Hand wash the finished fabric for retaining the colours
Anyways you will get the full instructions to use the fabric when you buy. Enjoy the fun.
