Troubles with Transparent white

Hi all, im printing with Van Sons rubber based ink. I find that when I mix pms colours that contain a large amount of transparent white the ink becomes quite sticky and its almost like it spreads around the edges once printed. Anything below 12 parts transparent white seems to be fine, but above this it all just looks wrong. Any thoughts? How would opaque white handle this, or should I look at another type of ink for my trans white?

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Try putting some reducer in your ink. Van Son has some litho reducer that comes in a black can. A little goes along way.

Thankyou - I haven’t actually used reducer or have any here in our studio. How does it actually work?

I use the same ink in our shop, but have had very good results. Describe more what you mean by spreading on the edges. Are you certain that the form is not being over inked or that the rollers are not too low? I often find that i actually like to add additional trans white in order to get a smooth coat on some images. I can agree that the trans base is sometimes more gooey than a denser color, which tends to mix stiffer, but i haven’t found it a problem on press.
Opaque white will not give you the correct color mix, it will create a pastel color, or whitening effect.
Good luck


Generally: Too much ink on the rollers, rollers are not adjusted properly, form is not at type high, or the ink IS NOT sticky enough. Transparent ink should not be used for typographic imaging, use opaque for type. You don’t have control over pigment variation with transparent.


I concur with Gerald on this one. I’d recommend opaque white instead of transparent. Transparent white is great for printmaking, but can be problematic for type. Some types, especially those made with Stand Oil as a base case be a bit slick on the press, and it puts down a less consistent print density.

Am I mistaken that opaque white will effect the color mix? Correct me if i am wrong, for I know you have both been at this letterpress thing for a while, but won’t the white make the colors, well, more white and chalky, like a pastel? Especially when we are talking about colors with a significant amount of base in the recipe?
Regardless, either the trans or the opaque white should not be creating a significant over inking problem on the form, it must be, as Gerald said, too much ink on press, or misadjusted roller height.
This has been my experience, but perhaps I am not clear on exactly the base preference you are referring to in this instance.
Thanks for the insight.

You are correct in that opaque white does alter the color when used in a formula designed for transparent white. Typically it does not “chalk down” the appearance though. It DOES make it whiter…. which is what it is supposed to do. Chromatically speaking, opaque white is more “powerful” than transparent so it takes less to accomplish the same amount of whitening.

One thing to keep in mind is that the modern PMS formulas and Van Son Rubber-Based Inks are designed more for offset use than letterpress, and thus the “on press handling” requirements are different. A formula that works wonderfully on an offset press may not always works as well on a letterpress….. so there is sometimes a need to modify a mix.

Typically in my shop, we use the PMS colors as reference chips only, and mix our colors “by eye” to match. We typically work out tiny batches as a test and then make a bigger batch for actual printing. Since we’ve done it that way for years, we assume that if we can’t see the difference, neither can our customers. Unless you are dealing with a designer who has exacting requirements, this approach is quite appropriate.