4 color process printing with letterpress?

Hi,

Just wondering if it is possible to do 4 color process printing with a letterpress. I realize registration would be a major factor. I’m not thinking about attempting it but just wondering if it is possible.

Thanks,

Bob

Log in to reply   14 replies so far

Of course it’s possible. The 4-color process is more of a photographic / computer process than one of printing. Once the negatives are made, it is adaptable to any type of printing. It was originally used with letterpress. Using photopolymer plates, it wouldn’t even be too terribly difficult, assuming you have color seperation software in your computer. It is certainly not beyond the capabilities of an advanced amateur printer.

Years ago I had the opportunity to work in a printing darkroom, and we did 4 color work every day. Nowadays, computers can do in minutes what used to take half a day.

Theoretically, it’s rather simple: You make 4 halftone negatives, each one filtered for a process color…. then make a halftone block for each one. After that, you print each block with it’s corresponding color…. magenta, cyan, yellow and black. Using good software, it would certainly be possible….. but you’d have to do a lot of experimentation to get it just right.

IF I were going to try it nowadays (but I’m not), I’d use the Corel or Adobe color seperation software that is now available , and then make some Solarplates from the negatives.

Hi winking cat press,

Great! thinks for the info. I’ll let you know if I ever get good enough to attempt 4 color process.

Thanks,

Bob

Hi. This discussion reminded me of some prints that Fritz Klinke posted on his Flickr site. They were letterpress printed with watercolor inks, but I suppose you could use any kind of transparent ink:

http://flickr.com/photos/[email protected]/369995683/in/photostream/

Barbara

Our shop did a menu for a high end restaurant back in 1964 in process on the letterpress. Not sure how they were made but we still have the copper plates the used. If I ever get a press large enough I’d like to try and reprint with them.

I first did 4 colour letterpress back in the forties, before a transparent yellow ink was made. In those days we had to print the yellow plate first, and it was extremely difficult to judge the amount of ink necessary to get a consistent print. We worked from the platemakers proofs as best we could, but it needed years of practical experience to be successful. Everything was judged by eye, there was no electronic aids to assess and regulate the color depth.
Unless you can guarantee register dot for dot, and we are talking about 150 dots per inch, you will be very disapponted with the results. Also in those days there was no humidity controls, and the paper was liable to stretch or shrink between the printing of the different colours, as presses that printed more than two colours per impression were never built.
It is possible but you need a lot of skill to obtain a good colour reproduction.

Lammy,

I hope you get the chance to reprint with those plates. That would be very cool!

Let me know if you do, I’d love to see it.

Thanks,

Bosco

Having been responsible for quality controlling 4-color process printing jobs for over 30 years, I feel that I need to toss a few reality-checks into the equation here.

The four process colors (magenta, yellow, cyan and black) are specifically designed to render a full-color image from individual forms (plates) that have been SPECIFICALLY seperated for this purpose. By their very nature they cannot faithfully reproduce every color of the spectrum, but have been the closest method possible (using only four colors). It was a real craft to produce these seperations for decades, but techniology has advanced and digital scanners now do the work. Getting four plates with the correct seperation, dot angles, etc. is only half the battle.

Getting these to all print perfectly in combination with each other is the other half of the equation. Most commercial printers with decades of experience would not attempt to print a 4-color process piece as four single runs. Paper stretch and shrinkage between passes being only one of the problems. A lot of commercial printers would do this work on 2-color presses, laying down two colors in one pass. This was tricky but worked fairly well, but the optimal method was to use a 4-color press where ALL the colors where printed and controlled in one pass.

The most critical part of the operation was the adjusting of the colors while on press. It is NOT simply a matter of inking up the plates and printing them. The colors have to be balanced and that means adjusting the inks during the MAKEREADY process until the right balance is achieved to produce the best results.

Just take a look at typical magazines from the 20’, 30’, 40’s or even 50’s and you can see how poorly “full color” printing looked by today’s standards. Most of those where printed in-line on 4-color rotary letterpresses.

I don’t want to discourage or spoil people’s experimenting or trying this, but just know that the reality is that it takes a great deal of experience and sophistication to pull this off, unless you can be satisfied with an “arty” look that does not perfectly match your original image.

Foolproof- you have pretty well hit the nail on the head. While POSSIBLE, and certainly not beyond the capacity of an advanced amateur, 4 color process work is not easy to do well. It takes a lot of effort and finesse to make a good picture.

Bob;
This is just a side note to this subject. When I saw BOSCO it got my attention. as the company I work for is Baltimore Office Supply COmpany. So we are known as Bosco. We’ve done a lot of multi-color work but it was done in the engraving or offset dept’s. Just recently I have started a two color job, and though the registration was critical the colors were not close together. And even though we’re still working the problems out the Boxcar system definitely made it easier.
Ron

I’ll have to ask how they printed that job. I know they never had a multi color letterpress. It could have been done on a windmill as they used to have two. Heck might have been done on four Golddings as they had that at one point too :D

My little Hohner is to small for the plates so unless the nuns let me try it on one of their presses or I manage to get a larger press at some time it won’t happen anytime soon. I could use the KS or Little Giant at the shop, but I’d feel weird about doing that without our pressman there to keep an eye on me.

4 color would be fun to play around with, but I will leave the actual 4 color process runs to offset and I will just stick with spot colors for stamp printing. I can do 4 color on a offset decent enough, never tried it on anything else though, I have always wondered if you could though. What happens if you start doing one color at a time and you realize something like your magenta is just to dark? Can you afford to just start over?

Two of the 8 tower presses where I work fulltime now are extremely digital that the computer will let you know if one of your colors starts going to high or low on the density number readings. It’s amazing, until of course the computer goes down and the operator actually HAS to look at their work, you have never seen so many high paid people with decades of experience break down and act like my two year old, thats actaully the real amazing part.

Brent W.
Mankato, MN

The First Chinese Pope:
I had the opportunity to witness what goes wong when printing 4 col proc by letterpress on a single colour machine. A firm in Auburn, Sydney, won the contract to print the colour frontispiece of the then Roman Catholic Pope of the day, sometime in the 1970’s, for the annual year book of that church in Australia. Foolishly, the production manager allowed the star apprentice to do the job on his best verticle Meihle. The lad printed his yellow plate first and because it didn’t seem to have enough ink on the page he loaded it up with yellow ink. There weren’t many densitometers in those days and there wasn’t any progressive proofs in the work ticket to give his inexperience any guide or any colour bars in the forme.
Even as the final colour, black, went on there was no way the oriental fella could ever look like an Eyetalian, and he wasn’t game to make him a black man. Something like 30.000 sheets were tossed in the bin. For once, it wasn’t me who copped a hiding!
William Amer, Australian
Compositor and Machinist

OK after reading that… . IF one had access to a densitometer would that actually allow for any benefit printing process work in letterpress? It’s not like offset where you put down such a thin ink film.

Also what order would you print CKMY or YKCM or CMYK

Greetings to all. My name is Andre I am new to this forum, on my first post. In the past two years I was searching for letterpress equipment and type. Now I am operational, ready to print!

I have made 4 color jobs before on Heidelbergs Windmill and a huge SBG Cyllinder, back in the 80s. I have never done it using photopolymer. I have experimented with color jobs using it and I realized that the photopolymer plate may ‘warp’ causing distortions, depending on the size of the plate. I will guess that you can use them on sizes as small as 5.5”x4.5”. What am saying is just based on my experiments, and the plates were made by the book: exposed, washed, dried and baked correctly.
I would say with certainty that if you make metal plates (zinc or whatever) it will work great. You can search the web and find a engraver.
As for using a densitometer to measure the density of the ink, I am not sure. Never heard of it.
As for the color printing order, it is basic CMYK order, but, lets say that the predominant color is a blue, in that case, run cyan and magenta, so you can control that predominant blue color. If it is a green, then cyan and yellow.
Hope my comment helps.

Cheers

André