Been looking at some 1960s film posters on display in the Uni Cafe. They’re huge and some are in colour, with painted graphics combined with photos that are literally – cut and pasted – onto the design.

The actual prints themselves, though, are made up of thousands of little tiny dots. Individual ‘pixels’ if you like? …seeming strangely ‘digital’, almost. I also remember these little pixel-print-dots in newspapers etc. as a kid. These dots must’ve been ubiquitous then, yet digital images and computers surely weren’t?

How did they reproduce these types of analogue images into tiny dots for mass printing back then?

I did my appreticeship in this oddly enough.

Basically you use a thing called a screen to convert your analog picture (on film) into dots on a printing plate. A screen is black film sheet covered in holes to let the light through (they come in different grades depending on how fine the work needs to be) So lightsource/picture/screen/plate leaves you a dotted image on the plate. Before macs it was all done manually on film so you’d make a page up by converting your images and type to film on a big flatbed camera then adding in pictures by literally cutting them out and pasting them into holes in other bits of film, you had to be good with a scalpel and ruler! Don’t ask about four colour printing as it gets complicated then…

It’s done exactly the same way now in terms of printing however the process of platemaking is now straight from Mac to Plate.

Ahhhhh…. mystery revealed! Cheers.

Tiny dots on a plate. Mad. 😯

colour had to be done with seperate CMYK ‘separations’ so the image was photgraphed with colour filters to make up each halftone plate.

Yup plates are still used to this day, the image on the plate picks up ink from rollers on the printing press and the background doesn’t as it’s damp and rejects the ink, that image then gets offset onto a rubber sheet called a blanket and the blanket is what actually contacts the paper and prints the image.
Watching a big web offset press at full tilt is weirdly hypnotic.

Just do add, the CMYK refers to the inks used (Cyan, Magenta, Yellow and Black) in the lithographic print process. So why was black referred to as K? I always assumed it was to avoid confusion with blue?

I really miss the print industry, I started out artworking on board, real cut and paste, or cow gum and wax. Way before macs.

Key. Your black plate is what was used as the key for register of the other colours.
I watched my well paid role as a final film planner disappear in a couple of years, technology eh!

Watching a big web offset press at full tilt is weirdly hypnotic.

+1

I get how monochrome things are printed

But how do you control colour? Is it as simple as etching the image onto the three copper plates, and the brighter the R/G/B* colour the deeper the etching and the more red/green/blue ink gets transfered to the paper?

*or CMYK, or any other colour seperating system.

Thanks joolsburger, a mystery solved.

Back then you took 3 photos of a colour image using a filter for each giving you three negs one for Cyan Magenta and Yellow.

Using the half tones outlined above you convert those images to plates and the dots are in slightly different places on each (like a rosette). That’s how it still works now but you use a lazer plate maker to create the plates straight from the ‘puter so the film part is no more.

The size of the dots is important and related to paper quality the better the paper the finer the image and all that.

I liked the print we did a lot of porno mags!

But how do you control colour? Is it as simple as etching the image onto the three copper plates, and the brighter the R/G/B* colour the deeper the etching and the more red/green/blue ink gets transfered to the paper?

*or CMYK, or any other colour seperating system.

It’s the amounts of each colour ink that determine it’s hue, saturation and lightness. If you add ink to a white surface, it now reflects the colour of that ink.

So, differing amounts of each colour produce all the colours of the rainbow.

CMYK is used in printing, which uses a reflective media and subtractive colour . RGB is for tellies and monitors etc and uses additive colour.

Some basic info about colour and how we percieve it here:

http://www.d.umn.edu/~mharvey/th1501color.html

The 4 colour plates will be printed onto the same bit of paper, to build up the final image thus:

Coo, that sort of makes sense. Do they have to do it in an order, or are the little dots offset?

Rewski – the k stands for khol.

Can’t beat a bit litho with a matt lam / spot úv combo.

Do they have to do it in an order, or are the little dots offset?

Yes, sort of, and they overlap:

God this thread reminds me just how much I’ve forgotten about printing processes. Bin over twenty years since I was studying such things in college. And things have changed significantly even in that relatively short time. And although I’ve produced loads of stuff what has bin printed, I never actually have to worry about such things as separations and that, because the printing firms just take my PS or Illustrator EPS files and turn them into the finished printed thing.

And you can print in full colour using C, M and Y only – the key just gives added depth.

The inks are trichromatic (sp?) so as they overlay each other they create the ‘mixed’ colour – a bit like putting a sheet of yellow Perspex on top of a blue one – it would look green.

I used to love traditional artworking 🙂