Ink: Trans White or Opaque White

Transparent white mixed with a color dilutes the color with a transparent base so the color appears watery. It basically allows one to see through the color to the surface of the paper. Opaque white prevents one from seeing through the ink so the printing seems suspended over the paper; think of the poster colors you may have used as a kid. The choice would probably revolve around whether you want the color to recede (blend with the paper), or advance (appear bolder), and what other colors you might be using it with.

Thanks, DTP. I usually use opaque with my own mixes, but it occurred to me that there might be a problem when ordering light custom colors. I did an experiment today with a custom blend ink and the trans white that they used worked fine.

Its been my observation that Transparent White’s slightly yellowish or ivory cast actually makes a difference when you are mixing up a color that has a large majority of Transparent in it. If you try and substitute Opaque White into the mix instead the color is off.

The PMS colors that specify Transparent White are formulated to accommodate the slightly yellower color of the ink. Substituting Opaque White directly will result in the color being skewed.

One thing you should keep in mind is that the PMS color system is designed to work with Offset Lithography, not with letterpress. PMS is not fully compatible with letterpress. Semi-transparent colors printed with letterpress will always be a bit different than the chart shows, and will tend to vary within a press run depending upon how careful you are with resupplying ink to your disk. (I’m sure you know this already, but other readers might not.) For this reason, opaque colors are preferred by most old-school letterpress folks. I have no idea what new-school folks prefer, my not being one of them.

What we do in our shop is to mix our ink “by eye” to match the PMS sample swatch, using opaque white. We simply mix them like one would mix artist’s paints, using the PMS formula as a rough guide. It is not nearly as hard or complex as folks seem to believe nowadays.

My way of thinking is that if it looks like the PMS color to my eye, it’s good enough to satisfy my customer. It must work as a philosophy, since in over 40 years of working like this, I’ve never had a run rejected for being the wrong color….. even when dealing with “Designers from Hell”.

The only problem I’ve ever had with the PMS book is with greens, which tend to darken when they dry. I agree that the PMS book should work as a guideline and a general mixing book. Batches of ink from the same maker can vary, so one should be prepared to make minor adjustments. I recommend reading the book Blue and Yellow Don’t Make Green by Michael Wilcox to have a better understanding of how to mix colors and how colors interact.

MKdeR- This is a good point and thanks for bringing it up. When mixing a heavy amount of white, I’ve taken to adding just the slightest amount of yellow to make it ‘right’.

WCP- Mixing using the PMS guide is how I learned and is definitely a good practice to get into. Truth be told, I have a couple jobs coming up using this ‘special color’ and I just wanted to take the easy way out. ;-)

DTP- Funny you should mention it, but I’ve had similar problems with Reflex Blue mixes getting a bit darker upon drying. Maybe the cobalt affects this change? Tends to happen on light aquas or blues- where it’s noticeable, of course!

The PMS book is accurate enough that I have been able to take premixed inks and alter them to another color by calculating what additional amounts need to be added. I learned to use the PMS book mixing ink for a two-color 50” Harris offset press, where I mixed ten or fifteen pounds or more of ink at a time weighing it all out on a Pelouze Scale.

I suppose some people find it more difficult to mix inks than others, but if you remember to add small amounts to make changes and use natural light to color match (flourescent bulbs will not show you the right color) with practice it becomes easier. Folks need to realize that color values are different, ie. Process Blue does not substitute for Reflex Blue, etc…

I haven’t found all the strange idiosincracies in letterpress vs offset mixes that people mention here and, after running letterpress posters for years, I know what it means to shovel ink onto a form. If the color doesn’t match, don’t blame the PMS book, just make the needed adjustments and get on with it. I understand that the newer PMS books have even more color mixes than before, which to me takes even more of the guess work out of mixing.

As previously mentioned…the pantone matching system is “designed” for offset. The main difference being the ink film thickness applied to the substrate. In offset this is 3-4 microns. That said…the actual PMS book is printed on gravure type (anilox) inkers WITHOUT a water system. Therefore the ink film thinkness is closer to that of letterpress. Pantone chooses this process because the introduction of a dampening solution adds an additonal unecessary component to manage and quite frankly it is less predictable and less repeatable. They do not have to worry about water pick up percentages, conductivity and PH. They simply get density and a spectrophotometric reading which is always the same run to run and book to book.

Because offset has such a thin ink film the color of the substrate is always a consideration for designers, and printers because this will change the visual appearence of the ink. An ivory stock will yellow a color(s)…even if it has no TW.

Virtually all commercial inks today are transparent(unless special order) the EPA and similar organizations have removed “heavy solids”. This is evidenced in that multi color presses print black first, followed by cyan, maganta and yellow last. You still see the black because the other inks are all transparent. This reality is why others above have mentioned colors look watery or washed…it is not the transparent white, it is that you can see through all inks commercially available today, a formula with TW will simply compound the issue because you are adding “transparency”. What you are seeing on letterpress is exactly what is seen on offset.

You cannot substitue opaque for transparent white and expect a good match result unless there is only a slight amount of Transparent white called for. TW is a Vehicle designed to take up space and/or cut the other parts.

Order the ink as called for on the pms book unless you want to achieve a special effect with regards to design, paper, opacity and images. I agree that mixing by eye can be fine but I suspect many are uncomfortable with this method and it is usually not necassary.