Tuesday, November 17, 2009

Screen printing: Traditional silk screen vs Gocco vs Yudu

I love printmaking. Whenever you give away an edition of a print, you don't have to say goodbye to it completely – you still have its brothers and sisters! At the same time, unlike a photocopy or computer printout, each edition is a unique handmade object of art.

One of the most effective and accessible printmaking methods for a designer is screen printing. About $100 can get you a rough setup with everything you need to multiply your work by the hundreds. Or, for just a little more you can buy either a Gocco or a Yudu. Both are small table-top devices that are designed to give hobbyist printmakers a compact home setup that's both easy to use and space-efficient. So which path do you take?

I've tried all three, and I definitely see the merit in each.

Since this is a very long post I'm breaking it up with internal links so you can bounce around. I'll start with some background about traditional screen printing, the Gocco, and the Yudu. Then I'll dive into a detailed explanation of how the methods differ, followed by a comparison chart summarizing the differences. I'll end with a final analysis of the pros and cons of each method, and recommendations for who might choose which one.

The one thing that I will not be covering in this post, but that I plan to address in a later post, is ink. That just adds a whole other level of stuff to discuss, and this post is going to be way more than you wanted to know anyway.




Screen printing is a process by which ink is pushed through a very fine screen onto a surface, like a t-shirt or some paper. On parts of the screen, the holes in the mesh are blocked, so the ink only goes through where your image is.

Probably the most common ways to block the screen is to coat it with a product called photo-emulsion. After it's air-dried, photo-emulsion washes out with water, as long as it is kept in the dark. Once you expose it to light, it hardens and and can only be removed with special chemicals. So, where you want your image to print, you cover up your screen to protect it from light, and then shine a bright light on the rest of the screen. You can then wash out the unexposed emulsion from the protected areas. Your image will appear as sections of bare screen, surrounded by areas filled in with hardened emulsion. This process is sometime referred to as exposing or burning the screen. After your screen is burned, you can push ink through the bare areas of the screen onto your printed surface. And that is pretty much how traditional screen-printing works!

You need two work areas, one where you can burn your screen and one where you do the printing, and there's a variety of ways to set them each up. Here's what my printing workspace looked like when we lived Dallas:


(I burned my screens in a bathroom, where I could make it dark when I needed to, and also wash out the screen when it was ready.)

In the late 1970s, a company in Japan came out with the Gocco. The Gocco is a little device made of brightly colored plastic that looks a lot like a toy, no more serious than a Play-Doh Fun Factory.


(image from feltcafe.blogspot.com)

But beneath its fun exterior is one serious little printing machine, condensing both the exposure unit and the printing setup into a device the size of a toaster. (There are also larger versions that allow for a bigger image, but I'd say the smallest is the most popular. It's big enough to print a wedding invitation, and the compactness is kind of the point.)

Gocco screens are coated in a heat-sensitive material, and where you want your design to print, the machine burns off the coating. So the idea of creating a screen that's filled in except in the image area is the same, as is the concept of printing by pushing ink through the open mesh.

Gocco was way popular in Japan for a while, and eventually gathered a cult following in the West. And then, they discontinued it. There are still loyal followers who seek out the supplies where they can for their beloved little machines, but they are a dying breed. Eventually all the necessary supplies made to go with the Gocco will run out. So sad.

Recently, an American company has tried to fill the void of the discontinued Gocco with a device called the Yudu. (I know, who comes up with these names?)


(image from whatdoyudu.com)

In many ways where Gocco differed from traditional screen printing, the Yudu is a return to the traditional method. But like the Gocco, it condenses the exposure and printing setups to a compact table-top device. It's not quite as small as the Gocco, but of course the trade-off for that is a much larger printable area.

All three methods share one advantage over some other printmaking processes: you can perfect your image before you transfer it to the screen. You can even do it in the computer, so you can be uber-precise, and use type and stuff.

So, traditional screen printing, Gocco, and Yudu are very similar in concept. The main differences occur in the details of how they're carried out.




Now that you have an idea of the basic steps of screen printing, I'll compare how each step is carried out using the three different methods. Again, while I'm going into some detail here in order to draw distinctions between the processes, this is not really a tutorial. (So if you try to follow it like one you might miss some key info!)

1. Get a screen.

Traditionally, screens consist of a piece of fine-mesh fabric stretched very tightly over a frame. The frame is usually either wooden or aluminum, about an inch-and-a-half thick.


(Image from printersedge.com)

You can buy a frame with the fabric stretched over it already for about $20 or more, depending on the size, and they can be used over and over again for a long long time, as long as they are cared for.

Yudu sells their own special screens that work with their machines. They are basically a compact version of the traditional screens – the metal frame is only about 1/8" thick. Also, their frames have a hole in each corner. These fit onto pegs in the machine, and they're used throughout the process help with keeping accurate image placement, a process known as registration.


(image from whatdoyudu.com)

Yudu screens sell for $28 each. They last a long time too, but I did some cosmetic damage to mine the first time I used it. (While the frame looks like solid metal, it's actually covered in a plasticky metallic tape. One one side of my screen the tape got partially pulled off. Oops.)

One major difference with the Gocco is that their screens are only made to be burned one time. You can print whatever image you burn into a screen as many times as you want, but since the screen won't be cleaned out and reburned, the frame is just made of cardboard. For registration, one end of the frame is notched to fit a corresponding part on the machine.


(image from paper-source.com)

Gocco screens vary in price since they are no longer in production, but right now the ones that fit the small machine run about $6 each on eBay.

2. Prepare the screen.
This step only applies to traditional screens or Yudu screens, and it involves coating the screen with photo-emulsion. Gocco screens come already coated with their own heat-sensitive chemical.

With a traditional screen, you use a special scoop to pull liquid photo-emulsion evenly across the screen.



This must be done in the dark, or under dim yellow light.

Yudu tries to simplify the process, and eliminate the need for a scoop coater, by selling sheets of dried photo-emulsion packaged between sheets of plastic backing.


(image from whatdoyudu.com)

Applying the emulsion sheet to the Yudu screen is a lot like applying a temporary tattoo. You wet the screen, peel off one side of the plastic backing from the emulsion, and lay the sheet emulsion-side down on the wet screen. Once it's dry, you can peel off the other plastic sheet, and the emulsion is left stuck to the screen. You do have to be very careful that the screen is evenly wet, and that no air bubbles get trapped under the emulsion sheet when you lay it down. Otherwise your screen won't expose right. Just like with the traditional method, this is done in the dark or in yellow light, but their emulsion seems to be a little less sensitive, because you can actually get away with just regular dim light if you're quick about it.

I actually prefer the traditional method over Yudu's "simplified" version. Though it does require that you invest in a scoop coater (around $20) and some liquid photo-emulsion (about $20 for a quart), it is much much cheaper in the end. The Yudu emulsion sheets are quite expensive – around $10 a pop. And that's for each time you burn an image! You can burn hundreds of images from a quart of photo-emulsion. Also, the Yudu emulsion sheet may be easier for a first-timer to apply, but I've found that after just a few tries with a scoop coater, you have a much easier time getting an even coat.

Here's the cool thing, though: while Yudu (conveniently) discourages you from using any materials that are not made by Yudu with their machine, I've heard that you can actually use a scoop coater and apply liquid emulsion to their screens.

To complete the screen preparation, you have to let the screen dry in the dark, and it must be horizontal so that the emulsion doesn't run or get thicker on one end. Here the Yudu does have a one-up, because it has a built-in light-safe drying rack with a fan.

Of course, with their ready-to-burn screens, Gocco wins the overall "easy" prize in this step.

3. Prepare your image.
With traditional screen printing or a Yudu, you print your image that you want to copy onto a transparency in opaque ink. The transparency will be layered with the coated screen so that the printed area blocks the light from those areas of the photo-emulsion, allowing them to be washed out later.

Transparencies are relatively easy to obtain, even ones that you can print on at home using an ink-jet printer.

Because Gocco screens have a heat-sensitive coating, you need a way to heat only the areas you want to burn out. This is done by printing your image onto plain paper using a carbon-based ink, and placing that under your screen. When the heat hits the carbon from above, it's reflected back up onto the screen, burning out the coating just in those areas.

It happens that carbon-based ink is also easy to find – both laser printers and photocopiers use it.

4. Burn the screen.

Here, the main issue with the traditional method is that you have to get together your own lighting set-up, which can get somewhat involved. You pretty much have to create a dark room with an exposure unit, but I won't go into all the details here.

Also, you have to figure out how long to expose the emulsion to the light. Too long, and the entire screen hardens, blocking out your image. Too short and you will end up washing out the whole screen, because none of it hardened. There's no formula because there are so many factors (the type of emulsion, the intensity of the light, the distance from the light to the screen...). You just have to get your set-up together and run some tests. Fortunately, once you find the key time for your set-up, if you do it the same way each time the exposure time should remain the same.

Yudu has an a built-in exposure unit. Also, if you use their emulsion sheets, they provide a pretty reliable exposure time on the packaging.

Gocco uses special flash bulbs to expose the screen to heat and burn out the image. These are for one-time use (they burn out with the first flash), and they're not cheap to replace. They are sold in packs for about $3 per bulb, and it takes two bulbs to expose one of the screens for the small unit. Also, just like the screens, they are discontinued, and therefore the price is unstable.

So, for burning your images, Yudu is easier than the traditional method, and more cost-effective than the Gocco. The traditional method is for those who like a challenge. (And who have an interior room without windows that can be tied up for a while as their dark room!)

5. Wash out the screen.

This is another step you get to skip if you're using a Gocco. (The burned-out coating on the Gocco screen actually sticks to the carbon-based ink on your master image, so when you pull your page away, the screen comes out clean already.) For both Yudu and the traditional method, you just have to rinse the screen with water while rubbing it with a soft sponge. Not hard to do, but kind of wet and messy.

6. Print the image.

Traditional screen printing and the Yudu both use a squeegee to deposit the ink. The Gocco has a neat way of trapping a layer of ink on top of the screen, and just by pressing down on it you push the ink through the screen.

The squeegee method actually requires two passes – one to spread the ink across the open areas of the screen, and then another to push it through. Both passes must be made with even pressure using the right amount of ink. You have to re-ink between each print, and if you're not careful, the ink can dry into the screen, requiring you to pause everything while you clean it out.

The Gocco method is comparatively fast and foolproof. The machine keeps the pressure even across the screen, and one application of ink lasts for several prints. Also, while the ink can dry and clog the screen, it doesn't happen as fast. Because the ink is trapped in that layer inside the machine, it's not exposed to air from all directions. This also makes the Gocco cleaner. So unless you're re-inking or you touch a wet print, you're not very likely to get it all over you. And getting ink on your hands isn't just annoying – it will ruin any print that you unwittingly handle before you notice it.

The one other thing you have to pay attention to in this step is where the image ends up on your print. Usually you're trying to center the image or line it up with something. There are two factors that could cause misalignment, or poor registration: the placement of the screen, and the placement of whatever you're printing on. The Yudu and Gocco have mechanisms to help with both of these issues, but with a little extra work and forethought, you can achieve proper registration with a traditional printing setup as well.

7. Printing multiple colors.

Registration really comes into play when you are printing something with multiple colors. If your one-color image is a couple of millimeters off from the center, but it has a two-inch border all the way around it, you're not going to notice the misalignment. But when you have two colors that are supposed to butt up against each other, a couple of millimeters really shows. This makes the extra help from the Yudu and Gocco even more important.

There are situations in which printing multiple colors is significantly easier. If all the colors in your design are spaced pretty far apart from each other (like if the closest distance between two different colors is, say, a quarter of an inch), you can expose them all onto the same screen. This is true for each method. With traditional printing and with the Yudu, you still have to do a print run for each color, blocking the other color areas with tape. But, not only are you saving screens (and the time it takes to burn them), you are keeping the screen in place while you switch colors, eliminating one of the two factors in registration. (You still have to make sure that what you're printing on is placed correctly.)

The Gocco has an even cooler trick up its sleeve. When multiple colors in your image are spaced apart, you can print them all on one screen, all in one pass! This is again because of the Gocco's special way of containing that layer of ink. It can be subdivided, as long as there's enough of a border in between. And when you press straight down on the machine to print, all the ink colors stay in their little divisions. (If you were dragging a squeegee across the screen, you can imagine how the colors would inevitably mix together.)

This ends up being a huge time-saver. A Gocco can cut printing time for a two-color print in half; a three-color design will print in one-third the time, etc. Really, you save even more time, because each time you have to register one color to another it gets more and more difficult.




So, that's A LOT of information to get through. I think a chart is in order, to help process everything. Let me see if I can pull out my old HTML skills from like 1997 and remember how to create a table...



Traditional
Gocco
Yudu
average basic setup cost
$1301
$200
$300

cost of additional screens
$20
$6
$28

screens are reusable
yes
-
yes
cost of additional emulsion (price per application)
less than $1
-
$10
cost of new bulbs for each exposure
-
$6
-
maximum image size
no limit
3-1/2"x5-1/2" 2
11"x14"

what you can print on
any flat surface, any size or thickness
can exceed image area, but must be thin enough to slide into the machine
can exceed image area, but must be thin enough to slide into the machine
combined exposure and printing unit
-
yes
yes

built-in drying rack
-
-
yes
easy registration
-

yes
yes
prints multiple colors at once
-
yes
-
ink application method
squeegee
press
squeegee
screen prep requires low light
yes
-
somewhat
availability of supplies
regular distribution in art supply stores, screen printing supply stores, and online
discontinued - limited availability in specialty stores and on auction sites
regular distribution in craft stores and online

Notes:
  1. This rough estimate includes a screen frame, scoop coater, emulsion, glass, flood bulb, transparencies, tape, spatula, squeegee, hinge clamps, and ink
  2. This information is for the smaller PG-5 unit, a replacement for the earlier B6.




Ultimately, what you're probably hoping to get from this is whether you should invest in a traditional setup, a Gocco, or a Yudu. Or maybe you have one of these but you're considering switching. Everyone's needs are a little different, so I'll try to explain what I like and dislike about traditional screen printing, the Gocco, and the Yudu, and give examples of who I think would prefer each one.

Traditional screen printing
pros: least expensive option; most flexible with print size and technique
cons: takes longer to master; equipment takes up more space
who should buy: serious artists and designers who want a setup with the greatest range of options; hobbyists who want to make prints larger than 11"x14"

Gocco
pros: fastest and easiest to use; extremely compact
cons: discontinued, making it hard to get supplies; limited print size
who should buy: collectors; people who plan to do only a limited number of runs; people with very limited storage space

Yudu
pros: somewhat easier than traditional method; considerably more compact
cons: most expensive option; somewhat limited print size
who should buy: hobbyists, or artists/designers who only need to do basic printing; people with somewhat limited storage space

I hope that you have found this review helpful!

20 comments:

  1. Great summary! I would like to hear about the quality of gocco vs. yudu, because I've heard that gocco is better. Do you know anything about that?
    Thanks!

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  2. Great information. Thank you for summarizing all of it. I've been curious about the Yudu.

    Quick side note: you can also use the sun to expose/burn your screen. There is a great video from Etsy Labs
    http://www.youtube.com/watch?v=SS2ntWPMICc

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  3. This is really fantastic! Great job. I bought a Gocco for my wedding this past May and we used it for all of our paper goods. Now, I'm looking for more ways to use it and am excited for all the other projects (although I guess it was kind of crazy that my first project on the Gocco was our wedding invitations).

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  4. Great article! The price breakdown was especially helpful.

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  5. Loved the article. I just bought myself an early christmas present. I was leaning towards the Gocco until If found a Yudu for less than $200 at ScrapbookToolkit.com. At that price, it is way worth it.

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  6. I'm so glad that all of you have enjoyed this article! I was hoping people would actually use it (as I wrote on and on and on.... :-) )

    Thanks also to Katie of savegocco.com for posting about it.

    Morgan, I have not noticed a major difference in quality between Gocco and Yudu when compared using the appropriate materials for the job. What I mean is, there's another variable about screen printing called mesh size – I'll have to do another post about that, but in short you have to use the right screen mesh for whether you're printing on paper or cloth. When Yudu first came out it only had the screens for cloth, so if you printed on paper, everything smudged. So, comparing a Yudu with the wrong screen to a Gocco with the right screen, it would lack the quality. I haven't tried the new finer mesh screens for Yudu, but I would guess it would be on par.

    Deanna, thanks to the link about sun exposure!

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  7. This is an amaizing article, thank you so much for taking the time to write such an informative piece!!!

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  8. wow! thanks for the info!! well written and super informative!!!
    :) Sarah May
    www.monsterinthecloset.etsy.com

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  9. Great article! Very informative!

    I was thinking about getting the Yudo just to create images on the mesh screen, then still use the Gocco to print announcements & invitations. I love how easy the Gocco is to print on card stock, and I have not found any information on how well the Yudo works when you are using card stock. Do you know of anyone who has done that?

    I will definitely check out the youtube piece on sun exposer .

    Thanks!

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  10. Thank you for this post! I am still hooked on Gocco, but I still think of straying. I bought some Stencil Pro stuff after hearing about it on Save Gocco, but I've yet to try that out.

    http://savegocco.blogspot.com/2009/06/stencil-pro-tutorial.html

    xo,
    leigh

    http://rhymeswithtwee.etsy.com

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  11. Nice information, I really appreciate the way you presented.

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  12. Thank you to the author and all the postings as well. There's not much info out there yet, and this was very informative. I will be getting the Yudu based on the info here.
    - E Hughes

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  13. Great article! I however, find it way harder to master Gocco than traditional screen printing. Love them both though, such wonderful things to learn. :)

    http://sophiegallo.blogspot.com/

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  14. Thank you for this site which I just found. It is very useful and informative.

    http://www.silkscreennow.com/

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  15. This post has been so useful to me! Any new news on using your own emulsion...or inks... for the yudo ( I would Imagine that you could use different inks right?) Any suggestions would be great! Thank you!

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  16. Can you comment on how the yudu compares with StencilPro?

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  17. thanks - this was so thorough! I really appreciate it.

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