I used to render on Blueprint copies (diazo printing) - and Chartpak markers would not dissolve the blue lines or bleed outside the lines.
With the black line copies I am now rendering - both problems happen. I know Chartpak are xylene based, and this is the problem. I know Prismacolor are alchohol based and do not have this problem.
One person suggested that I need to make sure the paper is a 'coated paper' and is a laser copy (not inkjet).
Does anyone know exactly what type of copy I need and what type of paper I need to resolve my probelm with Chartpak's?
Thanks in advance.
I've never tried it, but I've heard that applying light coat of spray fixative over the paper before rendering will keep the ink from bleeding. You could also print on vellum and render on the back of the paper, though your colors will be less vibrant (I personally like the look).
I use the same vellum technique, flipping over afterwards to fill in spots that need to pop. With a light hand it barely bleeds. Suitable for my tastes.
I don't think you will ever be able to get rid of the problem, as toners for electrostatic reproduction are essentially plastics with carbon black pigments. The lines are drawn on a photosensitive drum via laser/led charges electrostaticly which attracts the toner which is then transferred onto the paper where it proceeds through the fuser where the plastic toner is melted onto the paper. The toner grips the grain on the paper, but essentially remains on the surface. Diazo printing is a chemical/photographic type process in which the lines become part of the paper due to the chemical treatment of the paper. The lines are not just on the surface.
Because the xylene is a solvant, it "eats" the plastic in the toners, causing it to dissolve. As far as I am aware, there is no way to mitigate this. It is the same reason why you should be very careful with electrostatic prints in long term storage by preventing folding, exposure to heat, and rolling. The toner wil flake of at the fold lines and may "transfer" onto paper that is touching it. In fact, there is a well known image transfer method using photocopies and chartpak blenders.
If you want to continue using chartpaks with this printing method, you can check to see if your printer has a thick/cardstock setting which slows the paper down as it moves through the printer allowing more time in the fuser to melt more effectively onto the paper. Other than that, be very careful or switch entirely to another marker or colored pencil. As soon as my blueprint shop ran out of backline in the late 90's, I switched to electostatic and I made the switch to Prisoncolors at the same time. I still use some chatpaks for some situations where prismas don't quite have the same coverage or effect, but I have retired most of them. Diazo is obsolete, and chartpaks are incompatible.
BTW, switching to a higher quality paper will help...some. A good laser paper is denser and is a bit smoother than inkjet, and won't dry your markers out as much as it tends to wick less, which is why someone may have recommended it, as you can better avoid the lines, but the chartpak markers will eat the toner no matter what you do.
I use 24 and 35 lbs presentation bond (coated paper) with an Hp Designjet (inkjet) plotter to render using Chartpak markers with no smearing. If you are heavy handed some smearing may occur. The 24 lbs presentation bond (thin and smooth) works well for rendering, colors turn out a bit brighter and soaks up less ink (markers last longer). The 35 lbs presentation is a nice alternative as it is quite a bit heaver and has more tooth which works well for layering colored pencil and pastels with Chartpaks.
If you are plotting from AutoCAD or scanning hand drawings you need to use a designjet plotter to avoid smearing for the reasons Jason mentioned. Toner from copiers and laser printer will smear. If you are sending out to a reprographics company make sure you specify to use designjet plotter. Will cost a bit more but should be worth the added expense.