t shirt printing cornwall » pre press

Good single colour Screen printing deals

Steve — Sat, 08 May 2010 16:38:43 +0000

As previously mentioned in this blog short runs of screen printed T shirts are best kept to one or two ink colours if cost is a consideration. Each design colour in screen printing requires its own screen, and film. On a run of 300+ shirts these costs seem relatively small, but on a smaller run of 50 T shirts these costs are not very well absorbed. This can result in some very shocked responses from people requesting 4 colour front and back prints across 50 T-shirts.

Yet good promotional T shirts do not require the whole colour spectrum to make an impression, a good bold single colour graphic in one place on the shirt is often more memorable, and more eye catching than multiple multi coloured graphics in every position imaginable. So perhaps less is more? and a lot cheaper too.

On this basis Advertees are now promoting cheap single colour printing T-shirt Deals on short print runs of 50 and 100 shirts. The emphasis is on quality of print and T shirt as we think promotional should not mean disposable, Advertees think cotton is to precious a resource to be used in such a wasteful way, this is also a reason to avoid building diposability into a promotional design, people will wear a T shirt they grow fond of until they are thread bare, this is obviously very good long term promotion. So rather than supplying a cheap disposable product, Advertees have been able to bring the cost down through the quick set up times they are now able to achieve.

CMYK T Shirt Print-Screen Printing one rupee

Steve — Wed, 28 Apr 2010 19:51:43 +0000

Screen printing CMYK on white T shirts can produce results equal to that of any DTG printer, so at what point does it become impractical to create screens and put it on a digital printer? The print featured here was printed @ 85LPI using water based inks. We really should have timed the process to enable us to make comparisons, but unfortunately we forgot, timing jobs from start to finish is a very good practice to get into on multi colour set ups. A very rough estimate would be a couple of hours to produce screens, ten minute press set up, 30 minute press clean up and an hourly production rate of around 400 pieces.

Critical to making this process a competitive price on smaller print runs (I think 100+ T-shirts is where we can start to compete with DTG) is getting your separations and screen making process precise and repeatable, it is almost impossible to tell if you have a good print until you have run off the first T-shirt, if it has poor colour or unacceptable moire, you will be spending 30 minutes cleaning up your screens and squeegees before having to repeat the whole process again. (not having to clean up four sets of squeegees and flood bars is the best reason I can think of for converting to digital)

Accurate pre registration and a level press also make for much faster set up times. Once the screens are in place and you are happy with the result production is 10 x the speed of any DTG printer (if anyone wants to correct me on this wild guess feel free)

We recommend good quality T-shirts when printing at 85LPI, and the same is true for DTG printing. We find American apparel give excellent results, we were also very impressed with the bamboo/cotton mix T shirts we tried. Water based inks give a totally imperceptible hand and I think they also have some production benefits over plastisol for CMYK work. There are also environmental benefits. Grafco have formulated a water based binder especially for transparent process which we used here.

Are Retensionable frames worth the time and money??

Steve — Tue, 13 Apr 2010 19:24:45 +0000

Possibly the only reasons any screen printer can give for not introducing retensionable frames to their workshop would be the costs. And all the time involved in maintaining mesh tensions. Having used Newman frames for nearly a year now, we can only wonder where we would be without them. Retensionable frames have surpassed all our expectations with many unforeseen benefits being added to the list of ‘fors’ and the ‘against’ list has now been thrown in the bin. First and foremost we invested in Newman screens for faster set up times, using the pin registration system. This has worked like a charm not only in reducing set up times, but also the knock on effect of a better organized art department who now take full responsibility for the artworks placement on the screen.

More accurate placement of artwork on screens also allows for more control of halftones, high mesh tensions allow for finer meshes when printing water based inks, these two things combined have allowed us to produce screens extremely quickly, with very predictable results. We are never left trying to compensate for screen errors on press, our T-shirt printers are now faster, and much happier. The times where these improvements really make themselves known are on repeat orders where retensionable frames were not in use, this 3 colour water based discharge print previously had to be registered by eye, and then, after the first print, adjustments were made with great haste for fear of ink drying in the screen. Once up and running many adjustments were made to print and flood speeds to compensate for dot gain, or not enough ink down. This week we put the screens in their predetermined positions filled them with ink and printed a test print which was spot on registration. The job was then printed with zero fine tuning of print flood speeds. A retensionable frame removes so much frustration on press (especially when working with water based inks in the summer) that the time required to maintain them is more than worth while.

This print was produced for The Alarm who are presently touring the UK.

Easiway: a quick method of reclaiming silk screens after use

Steve — Wed, 24 Feb 2010 18:29:24 +0000

Reclaiming screens in a busy work shop can become a real problem for t-shirt printers, we have tried many methods and products over the years, most are unpleasant to work with, expensive and time consuming.

Easiway systems inc. seem to have found a formula which is quick, effective and more importantly a biodegradable, low odour product which is less hazardous to work with.

Dip tanks, used for reclaiming screens, have been filled will all manner of chemicals over the years, nearly all giving off vapours as they evaporate, this makes the work environment unpleasant and unhealthy to be in. Easistrip has none of these associated problems, and its effectiveness in producing a thoroughly clean and degreased mesh makes the screen making process a breeze. We have been using the system for nearly 3 months now, we have found it to be quick and clean.

Textile&Graphics Solutions Ltd are supplying the easistrip and easiway dip tanks in the UK, and can be contacted via e mail

textileandgraphics@yahoo.co.uk

or by phone Tel:+44 116 253 0090

It is pretty much essential to have a streamlined solution for screen reclamation, hours of work can be saved in this department. Poorly reclaimed screens will potentially cost a printer time later in the process too.

Screen printed T-shirt for Enochian Theory

Steve — Thu, 01 Oct 2009 21:30:00 +0000

Prog Metal Band Enochian Theory recently supplied a very challenging design to us. We immediately thought the design would be suited to the waterbased bleaching method known as discharge. The distinctive artwork was created by Robin Portnoff for the bands most recent album, and we are very pleased to have had the opportunity of reproducing this illustration as a screen print on T shirts.

Prior to this design we had never attempted a 6 colour simulated process using water based discharge inks, a job like this can present so many problems (colour is especially difficult to control), but when it works the final result cannot be compared to any other method of getting designs on to a Tshirt. The result is a fully ironable, breathable print. The earthy tones which are an inherent part of discharge prints, match this particular design perfectly.

The newly installed TAS dealt with this job brilliantly. We are already starting to wonder how we managed pre TAS. This job was run without flash cures, so an incredibly quick print run and a good energy saving. Newman screens also played a very important part of getting this job done without any hiccups.

Enochian Theory are now on their way to the Prog Power festival in Holland, with some UK shows on their return. Be sure to check out the bands web site, and myspace pages. There is also some great you tube footage. We like them a lot, a full 10 out of 10 from us. If you want to support this hard working band, buy their album, and if you like what you hear why not get the T shirt too.

Epson 4880 as imagesetter?

Steve — Wed, 30 Sep 2009 19:20:15 +0000

Years of printing excellent ultra black film on our epson 3000 lead us to believe a similar size, brand spanking new, epson printer would do the same job or an even a better one, but unfortunately it was not the case. Epsons new Ultra chrome inks are unable to create films black enough for producing quality films for silk screen printing. After the initial disappointment with the epson 4880s output to film we set about looking for a solution.

After several hours trawling the net it became clear the answer was accurips all black system. It was not the quickest decision to ditch all our coloured ink capabilities, as the colour print outs from this printer are amazing, but we were left with very little choice as creating good films is essential to creating good screens, is essential to creating good screen prints etc.

Finding a supplier of the all black system was not so easy, as it seems there is no UK supplier. Eventually we managed to find Serigraf a screen printing supplies firm in Ireland who were very helpful in sorting us out with everything we needed for the conversion. We spent an entire weekend colour printing to make good use of the no longer needed colour cartridges then set about purging the machine, and refilling with the black chromablast dye ink.

The resulting films are very, very good. The dye ink is as black as it gets, and combined with accurips software (I think this is the only RIP at present which offers an all black system) it is capable of producing extremely accurate half tone images.

The loss of our colour cartridges has been forgotten already as full colour T shirt prints become easier to produce, and this, ultimately, is our only requirement from this epson.

Discharge T shirt print using index separations

Steve — Thu, 02 Jul 2009 18:43:35 +0000

Index separations are very fast to create and very effective with some designs, the T-shirt design below is a good example of the kind of design which works well using this process. We chose to use discharge inks for a breathable print with virtually no hand.

Index separations have been covered previously in these posts:

5-colour-index-separation-and-waterbased-ink

index-method-for-screen-printing

and can be created in photo shop, screenprint separator is a useful additional plugin which has the ability to create separations, and export them for adding vector graphics and text to the design.

This 4 colour separation was printed wet on wet, the blending/blurring that occurs when printing waterbased inks wet on wet can help in producing more subtle gradations. Many screen printers will also agree the opportunity to print T shirts without the use of a flash curing unit (or 2) is both a time and energy saver.

Spring clean and mesh tensions.

Steve — Mon, 04 May 2009 12:56:05 +0000

Space is always an issue for a busy screen printing shop, the more space you have the better. It is also essential to use your space efficiently. So with this in mind we have finally started the mammoth task of dismantling the older part of the advertees screen library being kept in adjacent barn. The older part of the library is made up of wooden screen frames, some of which have not been touched for over ten years having moved on to Alumunium stretch and glued frames, and now Newman roller frames. So we have started the job of dismantling over 500 wooden frames, the frames will be used to run a couple wood-burning stoves.

Chickens check out the new floor space

Curious to know what kind of mesh tensions were achieved in the good old days, we put the Newton metre on a wooden screen printing frame, and it did not even register, we finally found one with a reading of 7 Newtons! Shown below next to our Newton Screen reading a healthy 30+.

So now we have potential for making good use of our adjacent barn, although a little building work is required when the clean up is finished, this is much needed new space to grow into.

Butt or Trap? Spot colours.

Steve — Mon, 27 Apr 2009 16:36:07 +0000

This is first thing we think about when separating your design for screen printing.

Butt or trap registration? What are they?

Trap Registration. This is essentially an overlap. When screen printing on dark garments all colours require a white underbase to improve there opacity. Without the overlap there is a danger the white will still be visible at the edges of the colour printed on top. Screen printing on textiles is a tricky business and very slight movement can occur in the fabrics and the screens, especially when heat is applied (the white underbase needs to be flash dried before applying the colours, some T-shirt brands will shrink at an alarming rate under this type of heat) trap registration creates a margin for movement. If applied correctly the overlap will be barely visible on close inspection. In a programme such as illustrator you can take the underbase back using a stroke of 0.5 .
Butt Registration. separations set up to register perfectly without overlaps. This type of registration is hard to achieve, but well worth the extra set up time on longer print runs on light shirts, especially when using water based inks. It helps to prevent bleeding of colours and the need to flash cure between colours. This type of separation can also be used when discharge printing. Butt registration requires a perfectly aligned printing press, if you have uneven palettes and worn registration pins you may want to stick with the afformentioned Trap registration.

Simulated process separation printed with waterbased ink

Steve — Mon, 06 Apr 2009 16:26:33 +0000

Simulated process separations were our choice for this T-shirt design, the subtle tones required for the egg were not suited to the index process. We find simulated process separations are a little more time consuming to create but they really can produce the highest quality prints.

We used 61T and 77T meshes for this print, 77T is not an ideal mesh for waterbased ink it held the half tone with no problem at all, but they required flood bar and squeegee tweaks on the machine to print well.

On the other hand 61T mesh printed with no problems at all, but the halftone on the blue screen suffered from moire patterning. This is possibly due to the mesh on the Newman frame being slightly off true square, as the yellow, also on a 61T mesh, was fine. Or was the yellow screen stretched off square? It is difficult to know for sure so a lot more care will be taken when stretching our Newman Frames in the future. With only slight moire on one screen we decided to go with it, there is no pattern visible on the final print, see rear side of duck above. The ideal screen angle for the 61T is what we are concentrating on now.

T-shirt printing:Gradients using half tone

Steve — Sat, 28 Mar 2009 14:43:40 +0000

Gradients require a little thinking about when screen printing. Moire patterns are tricky to avoid, many printers have their own rule of thumb calculations to decide on meshes, the most common are 3.5 or 4 X your halftone LPI = the mesh count you should use (imperial). The angle of the dot on the screen is also a big factor in avoiding moire patterns.

But none of these calculations really allow for a mesh below 196/77T, when screening water based inks by hand these fine meshes can make life very difficult. So can you put a 55lpi half tone on say a 34T and get a satisfactory result?

We think yes, in some cases it is ok. if you need to apply a large area of ink with a fade we think a coarse screen can do the job very well, the problem of moire is in fact reduced. However there is the problem of losing the finer dots on a coarse mesh, and this will reduce the tonal range.

This coarse mesh is not able to hold the very small pieces of remaining screen coat causing holes in some places,

at the other end there are less problems in the quality of the half tone, some very fine pin holes may sit on top of the wide mesh fibre and will not wash out, but the finished printed gradient does not suffer. The reason for this being it is a gradual change in colour over a large area, using only 2 colours. We would not like to attempt a full process colour job using such coarse mesh, but then we would probaly not print a full colour process screen print hand.

Sucker Punch

Steve — Fri, 20 Mar 2009 09:44:46 +0000

This T shirt design by Murkin uses 6 colours and is printed at our maximum proportions of 14×16. We prefer to print slightly under these dimensions especially when using half tones, but will make exceptions when customers are not in a hurry. This print was post old dryer and pre gas dryer, as a result it had to be printed using pthalate free plastisols rather than water based inks. This is our first multicolour job on Newman frames, a rather long set up time made clear the need to organise a pin reg system as soon as posible.

Newman Roller Frames

Steve — Sat, 28 Feb 2009 12:51:57 +0000

The recent purchase of some used Newman Roller Frames from MHM has forced us into adjusting our whole approach to screen making.

The Newman screens have been a massive investment in terms of time, but the benefits are already becoming apparent.

We were a little apprehensive about taking on Newman rollers as there are many screen printers who claim they are too difficult to use. But we decided the good reports were far more prevalent, many T-Shirt printers claiming they could never return to using glued screens. So what are the benefits of Newman’s? A tighter screen mesh (measured in Newtons) allows for

More accurate registration
Quicker set up times
A more uniform deposit of ink on the shirt

The screens can be re-tensioned, so these advantages will never be lost, and the life of the screen mesh is prolonged. We also benefit from savings on screen emulsion, and inks. However there are some problems to be overcome

The initial time investment is substantial, there is a lot to be learnt
The various sundries required are not easily available in the UK
Newman roller screens are a serious financial investment
Screens will tear easily at high tension

All the above are not really ongoing problems, the return on investment put these initial set up costs and frustrations into perspective. The screens are incredibly well made, our screens were acquired second hand, they had been very well used, but once cleaned up they were as good as new. We have not yet invested in a stretching table from Newman, and at the moment we are happy to stretch screens by hand, we can achieve tensions that are nearly double those of our glued frames. This was only possible with a few tips from Butch at Stretch Devices this video quite possibly saved us hours of torment, we are way behind Butch on his time of 7 minutes for a screen but working on it

So far so good, back to looking for locking strip, and extending the screen drying cabinet. Then our next job is to organise the pin registration system, this is where we should be able to reclaim all the time we have invested over the last 2 weeks.

Advertees T shirt printing with Newman roller screens

6 Great Sites for Vector Resources and Tutorials

Royzy — Sun, 25 Jan 2009 22:53:20 +0000

Here is a list of great sites for vector resources and tutorials. Regardless of your illustrating or design experience, there should be something in these vector sites for you. Each site generally contains a different style of resources to each other, so they are all worth checking out.

And remember, always check the owners terms and conditions before using freebies.

GoMediaZine

Go Media seem to be split between two grungy style sites, a graphic design blog and a product site. The blog is home to loads of original Illustrator tutorials, which cover quite a range of topics. The Go Media Arsenal product site is home to a variety of prepacked vector sets. They are generally $34.99 each from what I can see. Although you may just be looking for free stuff, these should not be dismissed, as they contain a considerable amount of artwork. They do also have a few Vector Sample Packs on offer for free.

Illustrator Tutorials
Free Vector Stuff
Themed Vector Packs (these require purchase – see site for prices)
Vector Samples

Bittbox

Bittbox is run by Jay Hilgert who describes himself as a ‘Freebie Maker’ and that is why he is featured here. He provides some excellent stuff, a mixture of Photoshop and Illustrator supplies. Only problem I found was that it could be difficult searching through the archive, because there is so much. Once I started using his tag cloud as navigation, it was much easier to find what I needed. This is a great site to keep an eye on.

Freebie Thread
Illustrator Tutorials

SpoonGraphics

Chris Spooner gets a mention again, as he previously appeared in my logo designer post. Chris has some great tutorials and freebies on his blog; one of my favourites being for the My Nite Life Logo. There are plenty of useful freebies here too, as well as an article on 50 illustrator tutorials that every designer should see.

Spoon Freebies
Spoon Tutorials

Vecteezy

Like it says – stupid name, cool vectors. This is pure resource, rather than tutorials. It is user submitted vectors and people have the ability to rate them. There is some really good contemporary artwork in here. It also has category filters and such in place, if you are looking for something specific.

Vecteezy Resources

Noupe

Although Noupe does not create tutorials, it compiles great lists of tutorials covering all sorts of creative areas. The post I have isolated has 60 tutorials to work through, covering a wide range of vector subjects.

Vector Illustration – 60 Illustrator Tutorials, Tips and Best Practices

Tutorial Blog

Like Noupe, Tutorial Blog compiles lists full of content ready for you to read through. The tutorials are aimed at beginners to intermediate, so have a look through to see what you might pick up from them. There are free vectors available too, mostly in the form of buttons.

Illustrator Tutorials
Free Vector Downloads

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If you have any favourite vector resources or vector tutorial sites, please feel free to add them in the comments below.

T- shirt design:Creating simplified artwork from a photograph

Julian — Wed, 14 Jan 2009 13:35:25 +0000

So you’ve got this idea about taking a favourite snap and converting it to something that can be printed in a minimum of colours, eh?
Plus you’d like to give the subject of your photo a different background just to jazz it up.

Sounds interesting, but just how are you going to do it?

OK, come on, back into the studio.

Butterflies, they’re beautiful. On anything.
T shirts included, so here’s my subject for the present little demonstration.

Actually, this is a really good image to use because it will reduce to monochrome exceptionally well. It’s practically black and white already and this is the first thing to consider – how your original image will convert to print.
A photo with little contrast, especially one that’s a little murky, may prove unsuccessful. You don’t want an indistinct blob, do you?
You won’t get the right kind of looks. Believe me, I used to wear one and I became shunned socially.

Anyway, the first step is to cut out the butterfly from the background.
You got photoshop? OK, open the photo, zoom in and grab the lasso tool. I’m setting the feather to 1 px (top, left of screen) – this gives a small fade to the edge of the lasso selection which reduces the sharp angularity of the cut out and I’m using the polygonal lasso tool. With this, you click anywhere on the edge of the butterfly and simply move along that edge, clicking as you go. The selection line will pay out behind your cursor in straight lines between each click. When you get to curly bits of the butterfly, space your clicks closer together to go accurately around the bends.

You can see here the lasso line being taken around the edge of the butterfly. Note that I’ve come away from the wee beast a little in the region of its antennae. With something as fine as these, it’s often better to go in later with the eraser tool and clean up.

When you arrive at your starting point, your selection will be complete and will be shown with a moving dotted line.

Copy the selection – Ctrl+C, or Edit/Copy.

Hit Ctrl+N to open a new document, A3 should be big enough, and paste the selection into it. It should now be on its own layer, above the background layer.

The first thing to do with it is to clean up the edges where necessary. I’m using the eraser.

Choose a brush size for the eraser which is appropriate to the area that you’re working on.
If you click and hold, then hold down shift, then move along the edge of the antenna then click again, you will see that area is erased in a straight line between the click points. Moving on and clicking with the shift still held down like this will result in nice, clean- edged erasure instead of the wobbly line you get when you’ve drunk a whole bottle of Wild Turkey the night before and you’ve got the shakes bad.

Your butterfly is clean.

Now it must have all the colour sucked away from it like jelly tots up a Dyson.

Various ways, various ways; but what works well here is to first go image/adjustments/shadow & highlight and take the shadows amount down and the mid tone contrast up. This effectively makes the image starker. Follow this by going image/adjustments/brightness & contrast and slide the contrast up to max.
That’ll do – it’s almost completely B&W.

Now, just because we can, let’s sit this stunner on a red background and make it a jaw dropper.

Ow!

Here’s how it’s done:

Create a new layer – Ctrl+Shift+N.
Open up the layers palette and look for the new layer. This should be called Layer 2. Grab it anywhere in the grey area and drag it downwards so that it lies between Layer 1 and the Background layer. When we fill it with red, it will now be behind the butterfly.
Go to the colour selection box at the bottom of the toolbar and double click inside of it. A large colour picker will appear. Pick out your red colour and click OK. The selection box will now show red. Ensuring that your new layer is still selected, go Edit/Fill/Foreground colour and your new layer will be filled with vibrancy.

Here are shown the layers palette and the colour selection box (circled in green).

The design is good as it is. Alternatively, in order to give it perfectly sharp edges and to clean it up still further, it could be be given the vector treatment. I would take it into Illustrator and trace it.

Settings for a good, clear trace.

There you go.

Vectorising sketched artwork and drawings

Julian — Wed, 07 Jan 2009 12:14:12 +0000

Somebody sends us their artwork that they would like printed out onto T shirts.
How is it done?
Follow me into the studio…

We get artwork in a whole variety of forms from finalised vector graphics to a quick sketch on a shopping list.
For this demonstration, I will use a sketch of Woody Allen put together in photoshop.

To start with, this has a wide variety of textures and is fairly colourful. The idea here, is to produce a stark, single colour print. Woody’s going to need simplifying and that means combining all the tonal areas into black.

One way is to adjust the levels (image/adjustments/levels), another way – and the one I have used here – is simply to pull the contrast up and the brightness down. When you’re happy, save the file.
For screening simple graphics like this, as with so many other things, vector is best. Vectorising a piece of bitmap artwork will give it ultra crisp lines instead of the blocky edges we associate with bitmaps.
Open up illustrator or another vector program, and take the image into it.
You can draw over the sketch using the pencil tool. This way, you can do some cleaning up of the lines as you go.
However, if it’s speed you’re after, you should always try vector tracing first. As well as, usually, making a very good job of it, tracing often introduces interesting and useful effects of it’s own.

Here we have the bitmap sketch (on the left) and a quick trace using the default live trace setting in illustrator.
Even at this size, you can see how a lot of the messiness has been cleaned up by the simplifying action of a vector trace.

If we go in closer, the difference in line edge clarity is obvious. This will print nice and cleanly.

It could well be argued though, that some of Woody’s character is lost – look particularly around the mouth where the shadow has become decidedly angular.
Here’s where the tracing variables can help.

This time, I’ve gone into the options and taken the path fitting down to 1 pixel. This gives a trace with a much higher fidelity to the original image. Too far in this direction, however, can result in the actual bitmap pixels being traced! If the original is of a low resolution this can happen, and will result in something which is still rough looking. You should make sure that your original image is of a good resolution to start with if possible.

Another setting which can make all the difference is blur. Using this tool can turn ragged lines into smooth, flowing ones which tend to look quite organic. For simple shapes particularly of an abstract nature, curlicues and the sort of floral patterns commonly seen in artwork today, this might be just the job. Also the blurring of a trace can impart a ‘glossiness’, or sort of plastic sheen etc. Depends what you have in mind.

Here’s Woody again with the blur turned up to 4 px. It’s often a trade-off, trial and error, but again, the higher quality the original artwork the better.

However, we have to try and work with what we receive and often all we have is a low quality piece of artwork. Tracing does not always work. Under these circumstances, we have to re-draw, and a drawing tablet, such as a Wacom can work wonders – so much easier than using the old mouse.

6 colour T shirt print, index separation

Steve — Fri, 31 Oct 2008 17:08:47 +0000

This T shirt design does not appear to contain a great number of colours, but we found it required six colours to make the job work well. We used index separations at 200dpi and took a very long time playing around with the palette of colours before it came right, we printed the T shirts with a combination of clear waterbased and opaque waterbased inks.
Setting the job up on the hopkins handpress allowed us to change the sequence in which the colours were printed. It is always interesting to try different colour sequences when printing index separations with waterbased inks.

200dpi is a bit of a challenge printing T shirts manually in six colours using waterbased inks, but it does allow for some experimentation. We are very pleased with the choices water based inks are affording us.

Halftone Dots and Screenprinting

Steve — Mon, 15 Sep 2008 16:36:41 +0000

A user guide to picking the best halftones

by David Foster. Positivity Ltd.

Screenprinters have a bewildering array of halftone dots to choose from when producing their imagesetter films, we look at why you might like to use particular dots and why some should be avoided.

Halftones come in two basic varieties FM (frequency modulated) and AM (amplitude modulated) screens, the same as radio signals.
Frequency modulated have the same basic dot size and vary the ‘blackness’ by printing more dots (i.e. frequency), as used by inkjet printers.
Amplitude modulated have the same number of dots but vary their size to increase the tone. This is what traditional imagesetters produce.

The simplest halftone is a round dot which just gets bigger.

SIMPLE ROUND DOT

This does the job, but as the dots join they create ’stars’ with sharp corners, these are ideal places for ink to dry in, closing up the dots and blocking the screens.
The dots join at around 71% to four neighbours. This gives rise to an optical illusion, exacerbated by the behaviour of ink, where a gradient shows a sudden jump in density, know as a tone jump.

The next stage of evolution was Euclidean dots.

EUCLIDEAN ROUND

The dots become a chequerboard at 50% and then become negative dots into the shadows – gets over the drying in problem but still suffers from a tone jump albeit at 50%.

If you use elliptical dots rather than circular dots, the long axis meets before the short axis, this gives two smaller tone jumps rather than one big one and looks a lot better.

SIMPLE ELLIPSE

Euclidean elliptical dots can be combined to address both printing problems.

Geometric or Line Screens have been fashionable in recent years, they give very tight rosettes and are very easy to find moiré-free screens.
Their great failings are that the highlights can become detached from the screen and can peel off the rest of the line.
The prints will also have a colour cast if used with standard settings, it is necessary to produce an ICC profile for proper colour.

SIMPLE LINE

A long axis ellipse gives the same effect as a line but can avoid the problem of highlights leading to the line detaching.

SCREEN LINE

FM screens are often used in t-shirt printing. They avoid all moiré, but can appear rough in the highlights.

FM/Stochastic Screen

Traditional Postscript screens are set with the Cyan, Magenta and Black screens 30° apart i.e. 30/60/90° with the yellow plate 15° away from the others.
This leads to unavoidable moiré between the yellow and cyan/magenta screens.
A hybrid of traditional Postscript screens for the Cyan, Magenta and Black plates plus an FM yellow plate avoids such problems.

A sophisticated screenprint orientated RIP such as Wasatch SoftRIP has the capabilities to produce a variety of screening options including the hybrid screening.

It has never been easier to produce professional looking screen positives from low resolution devices such as inkjet printers.

Design and typography for screen printing

Julian — Wed, 10 Sep 2008 08:50:27 +0000

For the use of screen printing, it’s a general rule that – design wise – boldness and simplicity work. You’re usually trying to convey a message quickly and clearly on your T shirt.
The same goes for most other forms of advertising – look at posters. People won’t usually spend time stopping and squinting. You have to hit them with interesting graphics/type – and usually just one or two main images.
Using few, bold, flat colours or monochrome design is a good way to go and has the added bonus of being easier and cheaper to print.
For inspiration, one great place to start looking is 2oth Century poster design. There are several ‘Ages’ to dip your toe into into, such as Art Deco, Constructivism, Futurism; as well as styles like comic book, jazz, film, theatre, tourism etc.

Take a look at this poster, Normandie (1935) by Adolphe Mouron Cassandre.
Monumental and minimal, you’ll never forget it. Cassandre was expert at conveying a message immediately. His posters for Dubonnet wine were amongst the first intended to be read by drivers passing by in fast moving cars. This kind of approach can look as good on a T shirt as on a poster.

Here’s another, similar example by Georges Dorival designed in 1928.

Here is a skyscraper drawing by Violette Engelberg. Hit them with that and they’ll feel it!

Very often, lettering is all you need. Typography is a powerful means of conveying mood as well as precise meaning.

El Lissitzky’s cover for the book The isms of Art (1925)

This is probably the most famous image created by the great Russian Constructivist Alexander Rodchenko.
It’s a lesson in the use of simple, striking type and dynamic blocks of flat colour which extend the calling motif in the photograph. It’s so good that it has been re-used in various forms umpteen times since.

Going back a little further, this is a billboard image advertising forthcoming productions in 1876 at a Glasgow theatre.
Such images were common in Victorian city streets. Note the use of various fonts to attract the eye to the details as well as the headlines. When treated with care, type-only designs can be rich in variety and strong in impact.

T shirt printers cornwall

5 colour index separation and waterbased ink

Steve — Sun, 07 Sep 2008 17:57:54 +0000

Colour separation requiring gradual tonal change. This kind of gradient would normally be achieved by a uniform halftone as it is easier to achieve smooth results, but we thought we would give indexing a chance.

Although indexing is not recommended for a subtle gradient, it does eliminate the problem of moire or screen clash, and when we are using coarse screens for a waterbased print this is very useful, we processed this design at 160 ppi and placed it on a medium mesh so we do not put too much ink down, but if your screens are coated well you could put the same half tone on a 34 mesh count if required.

The random dot will go on any mesh count with no moire, but how smooth is the gradient when printed.

Well take a look, obviously where the colours are similar in tone the transition is barely perceptible, you can see the dot on the dark blue to light blue gradient but we think it is still a very good result, it would have benefited only very slightly with the addition of another blue, we do not think it is worth the extra screen on a shorter run of shirts.We are certain the crew at global surf adventures will be more than happy with their T-shirt print.

index separations for waterbased T-shirt printing