Light colour mix not drying (using RB Trans White)


I’ve been trying to mix a very light blue (Pantone 5455U) with van son rubber based inks. The bulk of the mixture is transparent white (which is thinner/goopier than the color cans). For some reason, the ink will not dry (or absorb?) and produces a sticky sheen once printed. (Or, at least, it takes many days to dry). Is that normal when the base is mostly transparent white? The metal line block I’m using gets plugged up too.

I’m printing on 100% cotton, that I’ve printed darker colors on before no problem. Is this user error or perhaps my transparent white has gone off. It did have a slight layer of oil pooling on the top. I’ve had it for 5 years and have only used sporadically. Has anyone experienced this when trying to print very light tones?

Thank you kindly,


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If there was some oil pooling on top, maybe the ink components were starting to separate. Did you mix up the ink in the can before using it, including the pooled oil? If not, you might not have printed it with all the ink components which were needed to achieve the “drying” sequence as designed by the ink maker,

If the metal line block gets plugged, maybe you could try using less ink. If you don’t get the color using less ink, maybe you could make the ink color a little stronger. Make another small batch with, say, half the trans white of the original batch, and see what that looks like. Then you can go from there.

If the block is getting filled up, I would suspect you are using too much ink. Is the ink smooth and quiet when running on your rollers?

Have you tried mixing with opaque white instead?


Hey Geoffrey, thank so much for replying. The first try I just scooped up outside if the oil slick. The second time scooped out the top half, remixed and same result. I’ll try less trans white and see what happens. Will follow up. Thank you :))

Hi the Arm, I suspect you are right. I’ll try again. Maybe the third time will be the charm. I don’t have opaque in my palette yet but I wish I did for times like these. Really appreciate your help. Cheers!

I most often mix light colors using opaque white as a base.


On your next run, I would do a drawdown on a piece and see if it dries completely overnight. If not, add a three-way drier, (not too much, or it will never dry), and check it again before you go on press. Cobalt drier would work too.

Thank you all for your help!! So grateful :)

The third try was the charm. You were all right - I used too much ink. The different texture of the white transparency threw me off (in sound, by-eye measurement, and the feel). It was a good lesson to learn about working with very light colors.

I’m definitely going to order the opaque white. It would be nice to block some of the paper tone underneath.

BP, thanks for the tips. When I spoke to Boxcar, they mentioned using Tac Reducer. Sound like that might be similar?

I use soy base inks with good results. I use an overnight release Zip Set and also Gans Soy Base overnight. The slower dry time on press helps reduce on press dry up. I don’t like Rubber base because of very slow dry time. Gans also makes a letterpress white ink which is more costly but heavy body for both better pigment load and tack. Another option to reduce on plate ink build up and or salty image is to skip feed. Use less ink on the rollers but 2 roller passes for each impression

Dd - Tack reducer helps ink flow on solid areas, it is not a drier. Boxcar has a page which explains here…
Best, Bruce