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Mixing Ink

Hello everyone,

I was hoping someone could help me a little.
I’m not new to letterpress but have a basic enough question if anyone can help.

A few days ago, I chose a random colour from my Pantone formula guide to see how difficult it would be to create an exact colour. I couldn’t match the ink to the colour on the formula guide. Not even close.

I’m a little confused. I chose from the solid uncoated guide.
The colour I tried to mix is called 7457 U and it’s percentages are Pro. Blue 1.20
Ref. Blue 0.25
Pantone Black 0.05
Trans. Wt 98.50

The colour is a very light sort of duck egg blue/baby blue. It is very light.

By the way, my ink brand is Van Son and I think the inks are rubber based. I’m almost sure of it. Here is a sample of the tins I have -

http://www.vansonink.com/products/Quickson-PANTONE%C2%AE-Series.html

The inks have never been opened and are about a year and a half old. So I began mixing (not accurately). I added a big portion of transparent white to my sheet of glass and tiny amounts of process blue, reflex blue and black.

The transparent white is almost the colour of mushroom soup if it weren’t as grey in colour and more yellow/brown in colour. A sort of taupe colour. I was thinking I could never get a baby blue colour with the transparent white being so dark and then adding a little black and two blues. I starting mixing adding less than the required amounts of both blues, much less. The colour turned into a dark, murky, swampy green-blue and nothing like the formula guide.

Can anyone think of what I could have done wrong? Should I try it with opaque white? I’ve checked the formula guide and I’m sure I got the numbers right.

Any help would be wonderful. I hope I haven’t done something very obviously wrong.

Best wishes,

Rebecca

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Hello Rebecca,

It is my understanding that if your ink is Quickson it isn’t rubber base, its oil base. However, that doesn’t make any difference as far as mixing colors is concerned.

It sounds like after mixing the color you just looked at the quantity of mixed ink instead of trying to print with it or transfer it to paper. That doesn’t work. Ideally you have to print the ink under the same conditions you normally use to print on your press, such as the amount of ink you put on the press, etc. At the very least, you need to put a tiny bit of ink on your finger and “tap it out,” or in other words, repeatedly tap your inky finger on a piece of paper until you get a small area with a thin film of ink on the paper. This isn’t super accurate, but it will give you some idea.

You say the trans white isn’t too white when you look in the can. Remember, when you print with it you are only putting a thin film of it on the paper, so the beige color you see in the can will be reduced by probably hundreds of times.

You sound like you are assuming that mixed ink colors, when they are in the can, will look like the more familiar mixed paint colors in the can. This is very often not true. One reason for this is that inks are often more transparent, especially if you use transparent white. This is even more true of light colors which are made up largely of transparent white. When you look at paint in a can, you only see the top surface, because the paint is quite opaque. When you look at an ink like the color you mixed, you can look down into it because it is quite transparent. Because of this, it looks darker than it will print.

Another difference between inks and paints is that inks are much more highly pigmented. They have to be because when we print, we use a much thinner film of ink than when we paint.

In a color like yours which calls for a tiny amount of black, it is a good idea to leave the black out of the formula until you have tapped it out or preferably, done a test print with it. The black is there to make the color dirtier (as the ink makers say), or to reduce the chroma (as the artists say), or if you want, to reduce the brilliance….make it a little grayer. If your press has a tiny bit of black or a dark color left on it from a previous run, that will probably be enough to give the color the amount of dirtiness it needs. If you add black to the mixed ink and you add too much, there is no way to get it out and you will probably have to make a new batch of ink.

Regarding whether to use transparent white or opaque white, that is the subject for a whole other thread. Many letterpress people swear by opaque white, and it WILL make the ink in the can look more like the ink you print on the sheet. One big difference is that transparent white, when mixed in combination with other pigments which have at least some transparency, will let the color of the sheet come through. Opaque white will tend to mask the color of the sheet and, with other pigments, will allow you to print colors on darker sheets which you couldn’t do without it. In industry, colors are generally not mixed with opaque white (because it adds expense for one thing), and that is why the Pantone book does not use it in their formulas.

Transparent white is basically a finished ink, but with no pigment in it. Opaque white is ink with white pigment in it (titanium dioxide).

I hope this helps. If you have any other questions, let us know.

To all

My first foreman (75 years ago) told me the story of how they chose the typeface used for the newspaper: they gathered as many typefaces as they could, and put them through the process which would be used, and chose the one which was outstandingly good. Just a few weeks ago, I read the technical report on why that typeface was the best, it had been designed for the same method of printing which was being used, took into account the amount of ink spread which happened in that process, and also the “soakage” into the kind of paper. There’s nothing better than walking a little in shoes which one is trying on, to get the “feel” of them, so “roadtest” is the way to go. I found out many things that way.

So it seems the same principles apply to choosing ink — do the roadtest, and draw on the experience.

Alan.

I suppose this is an obvious one, but it’s not entirely clear from your post if you’re using a scale to measure out your ink. That would be essential to getting a close Pantone match. I’d also second Geoffrey’s comment on black. I almost always cut the amount of black requested in half initially, adding some in if needed.

I’d definitely second everything that Geoffrey said. The color of the mixed ink all pooled together will not be a good representation of how the color will look when thinly applied to your paper. Are you mixing these colors by weight or just by eye?

Something that I’ve taken to doing when tapping out the ink is to wipe the little bit on my finger onto a clean white rag with some solvent on it. The way the ink is broken down and absorbed seems to me to be pretty close to the color on the press and might be a little quicker and more consistent than blotting onto a piece of paper. However, if you are printing on a stock that is not white, then putting it on a white rag won’t be a good representation of how the ink will actually look on directly on your paper.

We’ve only used opaque white for mixing ink to be printed on colored stock to prevent that color from changing how the ink appears since they are by nature transparent. When printing on a colored stock we aren’t usually trying to actually nail a Pantone color though, then we just use the guide for a rough starting point, so I don’t know if opaque white can be substituted for transparent white in a straight 1:1 conversion and still wind up with the Pantone color. Opaque white is more expensive than transparent and that is reason enough for me to stick with transparent if the end result would indeed be the same. It probably would look closer to the intended color on whatever you are mixing though. What kind (and color) of surface are you mixing ink on? That’d also affect how the color looks while mixing.

Another option if printing on colored stock, which has been discussed here previously, is to print just opaque white and/or silver to block the stock color and then coming back with your actual ink color on top of that base, which will now be more true to the ink color than it would be otherwise.

For speed , i would just mix the colours of the mix without the mixing white . once i have the base colour i would add that in tiny quantities to opaque white till i hit the strength i want . You will find it simpler if you turn the percentages into grammes then your total quantity makes 100 grammes in most cases . if thats too much ink then call it half a gramme per 1% the total amount at completion will be 50grammes. This is wasteful but mixing this way requires less pigment colours but lots of white (opaque) ,it doesnt work all across the range of pantone colours but difficult light shades i find are easier produced this way . always add the colour to the opaque and add the colour in the tiniest amounts as opaque white colours up very quickly .

Ink mixing is by weight not by volume; that is the only accurate measure, and it is the basis of the Pantone system almost universal today. I wouldn’t mix less than 100 grams to hope for any accuracy, and a pound is the commercial norm: bad news for Kelsey printers. It is also recommended to start with the light components and add the darker components, testing along the way. Adding light ink to lighten a dark mix will result in pounds of excess ink.
The problem with using Pantome formulae is thaat the swatches are intended for offset printing which generally lays a thinner film than letterpress, and hence a lighter color since Pantone inks are transparent. That’s why “opaque white” is so often recommended here, to reduce transparency. But it is not totally opaque.
You can test an ink mix by drawdown, which is to put a dab of ink on an ink knife and then pull it across the actual paper to be printed, which will give an approximation of final printed appearance. Sometimes I will brayer it out on the ink slab and then pull the brayer across a long sheet, and the several rotations of ink deposit will tell how heavier and lighter ink coverage will appear. Less accurate it to put a dab of ink on the fingertip and tap it out on the sheet; to tap out ink takes experience.
And yes, Quickson is an oilbase ink intended for large sheetfed presses. It is not rubberbase. It isn’t even the oilbase intended for small presses. Mixingh white is normally the color of honey. Opaque white is used by many in mixing inks for letterpress, but verything depends on the press used. On a Vandercook or other press with cylindrical inking, I often use straight PMS mixes without modification, just run spare. For a platen with less ink control, I usually replace part of any pantone white with with opaque white, 20 % or more.
Others can now diagree.

My 2 cents. I use a Salter digital scale and set it to grams.

Example:
PMS 223
Rhodamine Red 7.8 %
Rubine Red 4.7 %
Transparent White 87.5 %

Using grams for weight to measure the percentages has worked great for the past 8 years.

You should start with the base ink without transparent white. So the two blues and the black. Do a tap out of it to see how it compares to the book. Take the tip of your finger and get a small amount on your finger tip, start tapping it out in a circle around the inital contact and keep tapping it out until your finger tip is not transfering any ink to the paper. Somewhere between the first tap and the last is a true hue of the ink you mixed.
Then mix in the white. I prefer to use opaque white but there are others that may not agree. Mix a small amount of the base color and then add the white to it. And again, a mass tone of a color is not a good indication of how the final color will print on a sheet of paper. A tap out or roll out of the ink will tell you more than viewing the mass of ink on a slab.

Wow everyone, thank you. That’s a lot to learn.

It’s a bit overwhelming :)

I’ll take all of your advice and hopefully will get a better result.

Thank you.