I haven't printed in months due to the climate wanting to burn my retinas off and dry everything in my screen way too fast. The weather's getting finally nice again, so I think I can tackle printing in the next couple of weeks again, yay! But I've been researching and talking with a screen printing professor at Arizona State U, thinking if anyone's going to know how to print year round, someone locally would.
Her advice: drop the use of Createx Lyntex ink (my old standby, guess it dries out too fast here), swap to Speedball and then add 7-10 drops of retarder/glycerine per half cup of ink, plus 5% transparent base even if I'm using extender base. (This sounds like mad scientistry to me) Or use the Speedball retarder base, which I only yesterday realized is its own base. Durr. I'm also going to up the humidity levels with a good humidifier eventually when I find one-- 10% default humidity seems to kill the inks too easily, especially in 100+ degree heat!
Anyway, so with this in mind I'm a little baffled-- the way I am used to making ink, I used a transparent base and then mixed in liquid pigments to get my appropriate color. I figure I can still do that with the Speedball-- I did that in a pinch a couple of years ago and it seemed to work fine. But I'm probably never going to use most of the Speedball colors directly out of the jar, but custom mix 'em. So what I'm wondering is what colors you think for a start I should nab to get a good line of colors?
Prereq' knowledge: I usually don't print bigger than 12x18" currently, small runs (~30, but would like to increase that to around 50 if I can properly calibrate my print area), use more transparent inks than opaque usually, 4-5 colors on average, pulling a layer every 10-15 seconds on a bad day.
I'm thinking I'll snap up a gallon of the transparent base and some overprint varnish, and I'm kind of on the fence whether I need extender or not-- I never used it. I have some leftover 8oz little jars of black, white, process magenta, primrose yellow, dark red, fire red... and a few jars of the retarder. Anyway I guess what I'm wondering is if you were going to have a 'kit' of colors to mix a variety of colors, which ones would you pick? I imagine I could get a lot of mileage out of transparent base and quarts of colors, but I wonder if I ought to get the other process colors, or what. These might be a good start anyway (with pigments added to customize color more), but I'm still curious what you guys would pick if you were starting from scratch again.
After I figure this out-- I'm so going to start work on my dual plans of building a paper rack and washout sink. Whee!
Conventional solvent evaporation ink is a fairly simple beast. One only has to look at the way it is made, no ink manufacturer uses retarder in the "stock" ink lines, or any of their ink lines for that matter, instead they use fast thinner, giving the printer total control over the rate of evaporation...or screen stability and dry time.
Try evaporating all the solvent out of your inks, then replacing the evaporated solvent with retarder.
I used to mix ink from base/extender and pigment for a client who required a nitrocellulose ink for overspraying with clear lacquer, since nitrocellulose inks were phased out in this country I had little choice but to start from scratch. A shit awful job mucking around mixing rockhard pigment and clear/extender, but the detail of the image dictated drastic measures or UV, UV was out of the question, so....
Grab a gallon of base/extender, take the lid off and watch that shit evaporate over a week or more, stir it a few times a day so as to avoid a skin forming over the top, you will notice the viscosity change over time from a usable liquid, to a thick unusable paste, once you figure a fair bit of the solvent has evaporated, replace the lost solvent with retarder.
Obviously your dry time will be increased, but the ink will remain super stable in the screen, marginal drying in, if any. Do the same evaporation method with your pigment.
If you do this, the only effect humidity and temperature will have is over your substrate. I used to print this stuff through a 355? (150/31) mesh, all day, no problems. I find this method a LOT more stable than switching out to waterbased, or another conventional solvent evaporation ink.
Your choice of colours should be even simpler, start with the 3 primary colours, Yellow, Magenta, Cyan. Then add secondary colours from stronger pigment if required, if you only require transparent colours, just mix the secondary colours from the primaries. Add some white and black and you have almost every colour achievable in the PMS book.