transparent white

If indeed the same press conditions, etc., it has to do with your mixing. You might need to add an additive such as magnesium carbonate to stiffen the newly mixed ink to the same viscosity of your black and red.

Gerald

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Gerald and paul, thanks for your help. I wonder if I can use opaque white instead of trans white with magnasium carbonate or not. what is difference?

It depends on what you are trying to achieve. Transparent inks generally show ink coverage/ density problems sooner than opaque ones so if you can use opaque inks you are better off. This is especially true if, as Paul mentioned you are overinking.

The only times I use transparent ink is when I’m printing one color over another to achieve a third color, or when I want to show some paper character through the printed image….. or when I’m printing a very light background tone. Other than that, I generally use opaque ink.

As far magnesium carbonate goes, I’ve never used it much.

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hi ave9river,
I wish I knew more about colour theory than I do, but in my experience there is significant difference to the impact of opaque vs transparent white. While transparent simply reduces the intensity of the colour (like adding more water to water colours), opaque white changes the nature of the colour (depending of course on quantity) moving the colours toward pastel. I do like Halfpenny Press’ comments about the look of the colours on the paper.

Steph

Thank you all. You are helping me a lot. Please check below that I understand you right.

1. When I use Trans white, I need to use stiffening additive.
2. Stiffening additive thickens ink but doesn’t give opaque effect so it is different effect from opaque white.

after I figure this out, what I need to do is lots of practice to have a good sense of ink. Thanks again.

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Paul said: “My best advice is to find a local ink maker that you can work with to get exactly what you want. In the long run you will be much happier.”

Hmmm. Local ink maker. Do they exist anymore?
I had the great good fortune to work with the old fellers at Cardinal Colors in Chicago in the 1980s, still have a few ounces of their “Letterpress Black” verrrry slow drying oil based in a can labelled 1984 I think.

Of course, as with most good things, they are long gone.
I would LOVE to find a source for real oil-based letterpress inks. I note that Harold at Boxcar uses rubber base for their work, which I expect makes sense considering the volume, and the fact that the rubbers are stiffer than equivalent oil-based offset inks.

I’ve still got about half a pound of Mag Carbonate (from the Cardinal Colors days), which I use quite liberally to counter the squishy fluidity of the offset inks, but I’m at a loss to quantify this. Seems like every ink requires a different amount.

Is there a percentage addition that one might aim for to standardize the ‘conversion’ from offset to letterpress?

Another can I have from Cardinal Colors is labelled “Sharpness Gum”… Wish I’d asked the old guys what the heck is is… Any ideas??

Charbonelle makes some very fine inks that are fantastic for letterpress. They are very heavily pigment loaded, and extremely well milled….. so they put down an image second to none. Nowadays they market them as “etching” ink, but it is the same formulation as their old “oil based printing” ink.

The other good oil based ink is from Faust. They still make a great “old style” letterpress ink that is as smooth as glass.

I really like Charbonelle also. Although I used Transparent Lake to make a pale, pale purple using two other Charbonelle inks and I thought it was fine until I needed to print more of a particular project and used a tint base extender (Graphic Chemical) along with those two same Charbonelle colors for the pale purple. It wasn’t evident at first but few months later I noticed on the prints the color made with the tint base was much cleaner than that made with the Transparent Lake. It’s almost like in the Trans Lake the color was fugitive but was not in the base. The print were both stored in the same drawer for the same period of time. I don’t know enough about ink formulation to say why, but it definately does pay to test different inks even if it seems they should produce the same result.
Connie

sorry to hear about your problems using transparent white but you will always have a mottle effect especially on smooth coated stock. Try experimenting with hard to soft packings and the use of a frisket my also help.
Mike Eustace 35 years in the trade!!