Mixing opaque inks

Nothing?

Jonsel,

There are a number of posts on Briarpress about mixing inks. Which colors do I need? Follow the pantone guide?
Is oil different than rubber based? Offset ink vs. letterpress ink? And about using transparent white vs. opaque.

I believe I can produce almost any color you are looking for with just a few base colors. I do not use the guide, although I might focus on a specific pantone color to shoot for.

When mixing a solid color I always start with opaque white, as much as 50% of the volume or more. I then add the colors until I reach the desired color. I tap it out using eraser rather than my finger, although many have various opinions on this, to see how the color will look on the stock I am printing.

I’ve mixed a lot of things using transparent. Again starting with the transparent white and mixing in the colors. It is very difficult to add white to lighten a color, it is much easier to add color (pigment) to white to reach a shade.

Having said all of this, I wold always say the you must try it, experiment with the colors that you have and the color you are trying to achieve. Remember that the density of the ink film and the color of the paper will influence the end result.

Also, the artwork will have some effect on how the color is perceived. I did a piece recently where I printed a line of type in a 36pt Serif face. I had mixed a deep charcoal color, (white with some black and a tiny bit of blue). On the other side of the sheet I printed 12 pt type using the same ink. On the larger type it was easy to see it was gray, on the smaller font it looks black.

Good luck, as some of the other on BP say, get ink on your shirt, and test it out.

Steve

When printing offset I mix 50/50 trans and opaque. It is not letterpress but you wanted responses. The only time I had a problem was when the paper was not white and showed through. When mixing use I use the Pantone guide and keep the same total amount of white just 50/50. Do a quick pull down test to check the ink before using. Good luck!

Could you tell us a little more about the job, such as what color you are needing to mix and what color paper you are planning on using? Can we assume you are doing this to make a light color ink show up better on a dark paper?

Sorry for not being clearer. I’m quite comfortable mixing inks usually. I’m printing on black stock and was hoping to see if I could mix a color using opaque white in place of the Pantone-specified transparent white. I was looking for others’ experience doing similar. I ended up using roughly a 70/30 mix of Opaque/Trans White in the formula and it came out ok.

If you are printing on black paper you need to print an opaque white base first. Then print with your color on top of the opaque white. Register has to be perfect…

I posted this response in Oct 2010. I’ll see if I can up load a pix. Also uploading a pix of a job that was hit once, twice and then also hit as a dry trap which comes out the best.
I printed 3 vibrant strong colors on black cover stock a year ago. I printed 2 hits of opaque white, then two hits of each of the three colors. Orange, lime and purple.
They came out so vibrant that they look like foil stamping.
There are two tricks: one is very good registration so that you “trap” (overprint) the previous layer of ink perfectly. (expect a reasonable number of rejects), start with far more pieces than your finish count.
The second is “dry trapping”, that is print the second hit when the first ink is dry.
Gold and silver inks get their color from the gold or silver metal pigments and are inherently opaque. You should be able to get a reasonable job without the opaque white, but it will help. (Transparent white will help as well.)
Good luck
Steve

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Look, with ink mixing, opaque white is the go. Transparent white is really an extender. The nice thing with opaque white is that it really allows easy overprinting. The joy of letterpress is knocking out underlying elements, mostly successfully, whereas in Offset underlying areas are generally knocked out. Steve has some very good words too. I love rubber based inks, intense colour and great economy.

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