Color is a shape-shifting and changeable thing. When the light changes, or the adjacent colors change, or the finish changes - basically, if anything changes, it looks different, sometimes really different.
Anyone who's ever chosen a paint color from a little color chip and then been surprised by how different it looked once it was up on the walls knows what a slippery fish color can be!
Of course, the more we do anything the better we get at it, and judging how colors will work in certain situations is something we all get better at with with practice. But I don't think it's something that ever completely loses its mystery. Or I hope it doesn't, because as much as that mystery stresses me out sometimes, I kind of live for the reveal of how colors actually look printed. And I spend a good amount of time testing and adjusting on the press to get colors I love.
One of the challenges I like (most of the time) about letterpress printing is that it adds extra layers of elusiveness to color selection. Printing is actually a final stage of design as I dial in the colors rather than just fabricating finished designs.
Why is this the case? Well, -
Letterpress ink is transparent, making it an especially slippery fish to catch.
The paper you print on shows through the ink to some degree and affects the color. Yup, even a change from a cool white to a warm white paper will likely change what the ink looks like a bit, never mind something drastic like printing on a dark or bright paper.
Are you using a lot of ink or a little? The same color of transparent ink can print in a range of tones depending on how thickly it's been applied on the press. Inking a letterpress is super old school and approximate and done by feel and sound - you listen for how the press sounds as the rollers run over the ink disk to tell roughly how much ink you have on the press. The more ink you use, the darker the color you'll get.
Mixing colors by hand adds another layer of variability.
There are a few basic Pantone ink colors that can be mixed in different ratios to make probably thousands of numbered Pantone colors - or your own countless made up colors. You can buy premixed ink in any numbered Pantone color you want, but if I did that I'd be committing to a color before I printed a design with it. (Not my favorite thing.)
Also, I use so many colors that buying them all premixed would be pretty expensive - though, hand mixing ink takes time, too, which is money, so it's expensive either way! But this way I get more ability to tweak and shift colors.
Printers mix colors using a Pantone formula guide, like the one fanned out above next to a digital mock up of the new Persicaria Anniversary Card. The colors in the digital print are usually a pretty good approximation of the final letterpress printed colors I'm looking for - but they're never quite perfect.
One of the two colors I picked for this design was Pantone #241-
13 parts Rhodamine Red
3 parts Purple
1 part Black
It's the grape-y purple at the top of the ink test sheet below:
I eyeball the percentages of the basic colors when I mix ink and adjust as needed. Even if you weigh out the colors for more precision like some printers do, hand-mixing ink always has some fuzziness involved. And you can't really tell what the ink is going to look like as you're mixing it - it's much darker as a big blob on the slab than it will be when it's spread out super thin on the press.
We tap out very thin layers of ink to see how the color is looking. On the test sheet above, you can see the range of light to dark purples you can get from 241 depending on how thick the ink is on the paper. And see how the lines in the paper show through? That shows how transparent letterpress ink is and how much the paper color will show, especially with pale ink colors.
When two letterpress ink colors overlap you get a somewhat unpredictable third color.
You generally print one color at a time on a letterpress, but you can get a magical additional color by harnessing the transparency of the ink and overlapping two (or more) colors in your design. This extra color is a little unpredictable - you can try to smear the two colors over each other to test the effect, but, as you may have guessed by now, it's rarely ever the exact same effect of pressure and ink densities that you'll get on the press. Seeing your printed overlap color is always a little bit of a fun surprise.
Let's look at an overlap example:
Here's the first color of the Persicaria Anniversary Card - a nice pale tawny pink (Pantone 197 + more yellow + a speck of black).
It took me a little while to get this pink the right amount of warm - I wanted it still pink but almost peach.
Side note - Putting this color next to the grape-y 241 will make it appear even a little warmer/peachier than it does here when it's by itself.
Side note #2 - I also love the variation in the ink coverage within the leaves - much more interesting and lively than totally solid and rigidly uniform color, I think!
Ok, back to our overlap - now we print our Pantone 241 over our tawny pink:
You can see in the photo below how the color that looks grape-y purple on the press becomes more of a maroon on the finished card after overlapping the pink.
There is unadulterated purple 241 ink in the flowers, though it's a little hard to see the difference at this resolution. The three color effect is intended to be a bit subtle in this design.
For a more pronounced example of color overlap, we have the Mother's Day version of the Persicaria design:
The pale blue and spring green overlap to make a pretty dramatically different dark green in the leaves, don't you think? This palette reminds me of walking in the cool spring woods with my mom. I wanted it super fresh feeling.
I also love the totally different feel of the anniversary card palette - warm, deep, sincere, and not too sugary.
So there you have it - we navigated the many variables of ink mixing and printing to get just the color effects we wanted! A good day (or two)'s work, for sure. Time for a glass of wine - maybe one that's the color of 241 over 197.