Pantone Guide: mixing ink with opaque white

Hi everybody
I use the pantone guide to mix my inks. I use pantone offset-inks (in Switzerland there are no letterpress-inks). This mostly works fine. Except when I have to mix inks with white. I’ve already learnt that offset ink use transparent white, but for letterpress I mix with opaque white or “blanc mélange”. But then the pantone scale is useless, at least this is my experience. How do you mesure the inks (grams) when mixing with opaque white to get the desired pantone ink? Thanks very much for sharing your know-how.

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I think most of us use offset inks. I mix my inks with transparent white. Sometimes it can make it more runny than I’d prefer, but that seems to work best for me. If you’re doing any overprinting, you can’t use opaque white in the mix.

I learned awhile ago from a great pressman to use both opaque and trans white in equal parts with letterpress. So for example pms 1505 calls for:
50.0 orange 021
50.0 trans wt.

I use:
50.0 orange 021
25.0 opaque wt
25.0 trans wt.

Works like a charm.

I’m with jonsel…..I use transparent white. However, I think a lot of letterpress people on this site use opaque white, and whatever works for them is great, as far as I’m concerned.

The key issue to me is that the transparent white is yellowish by nature and the PMS formulas account for that fact. If you mix with opaque white it typically ends up bluish in comparison to the swatch. This can be corrected of course, but in a commercial setting there is only so much time for trial and error. You can arrive at an approximate formula for correcting it but it’s not an exact science!

If you want to use opaque white with a PMS mix, it would be a good idea to add the opaque white at the end of your mix, and do it gradually until you get the color you are after. Opaque white is a denser and heavier ink, so if you use a mix designed for transparent white the mix would be slightly off, but not by much.

I used to mix PMS colors for the printers in the shop in which I was first apprenticed - ten to 15 pounds of ink at one time, always using the PMS books, and always weighing the amounts. I have trouble understanding why printers today have such a hard time mixing with a PMS book, I’ve never had trouble mixing even very small amounts. I have learned to mix with existing PMS mixes I pick up cheaply, and add the necessary colors to change it to another color that is needed.

Paul

Thanks everyone for their comments, ideas, advice, I appreciate a lot! As I can read from your posts, mixing the ink, especially when white is asked, even with the help of an PMS guide always means trial and error in letterpress printing. This is fine with me and what I love about printing. It is just sometimes when I work for customers I thought I could “rely” on some scale/guide. But finally it means using the PMS guide and exercising/trying out and with time relying on myself and my experience… Thanks again and Gott grüss die Kunst ;-).

AMRA.ch may ????? do some letterpress inks, also Michael Huber of Munich do relief inks I believe -Hostman Steinberg may do some thing useful, or consider inks for stone lithography made by Joop Stoop various suppliers eg Polymetaal but not suitable for volume high speed work, more hand printed. Perhaps there are not local printers closing down their works so old letterpress inks are not available. Check out the various swiss printing museums to see what they use via this link??
http://www.aepm.eu/links/

There are some good letterpress inks available from Lawrence in the UK as well.

Thank you Jonathan and Thomas. But in general the offset inks work fine (just have to put them in the fridge sometimes, because a little to runny). And they are affordable or I even get “old” offset-inks from other printers for free. The “problem” is mixing offset-inks with white for letterpress according to the pantone guide, because the transparent white doesn’t work for me. But I did some mixing yesterday and trying some of the advice I got from the briarpress-community and it was successful :-).